The TextBox Control

ChapterTextAlign2 - Building C# ApplicationsGets or sets how text is aligned in a TextBox control, using the

Part Two - The C# ProgrammingHorizontalAlignmentLanguage enumeration

Chapter 3 - C# Language Fundamentals

Chapter 4 - Object-Oriented Programming with C#

ChapterFun 5with- ExceptionsTextBoxesand Object Lifetime

Chapter 6 - Interfaces and Collections

ChapterTo illustrate7 - Callbacksome ofInttherfaces,more exoticDelegates,aspectsandofEventsthe TextBox, let's build a multiline text area that has been

configured to accept Return and Tab keystrokes and supports a vertical scroll bar. Here is the configuration

Chapter 8 - Advanced C# Type Construction Techniques

code (assume you have already defined a Form-level member variable of type TextBox named multiLineBox):

Part Three - Programming with .NET Assemblies

Chapter 9 - Understanding .NET Assemblies

Chapter// Your10 -firstProcesses,TextBoxAppDomains,. Contexts, and Threads

ChaptermultiLineBox11 - Type.Reflection,LocationLate= Binding,new Systemand Attribute.Drawing-Based.PointProgramming(152, 8);

PartmultiLineBoxveragingFour - .Textthe =.NET"TypeLibrariessome stuff here (and hit the return and tab keys...)";

multiLineBox.Multiline = true;

Chapter 12 - Object Serial zation and he .NET Remoting Layer

multiLineBox.AcceptsReturn = true;

Chapter 13 - Building a Better Window (Introducing Windows Forms)

multiLineBox.ScrollBars = ScrollBars.Vertical;

Chapter 14 - A Better Painting Framework (GDI+)

multiLineBox.TabIndex = 0;

Chapter 15 - Programming with Windows Forms Controls

multiLineBox.AcceptsTab = true;

Chapter 16 - The System.IO Namespace Chapter 17 - Data Access with ADO.NET

Part Five - Web Applications and XML Web Services

Notice that the ScrollBars property is assigned a value from the ScrollBars enumeration, which defines the

Chapter 18 - ASP.NET Web Pages and Web Controls following values:

Chapter 19 - ASP.NET Web Applications

Chapter 20 - XML Web Services

public enum System.Windows.Forms.ScrollBars

Index

{

List of Figures

Both, Horizontal, None, Vertical

List of Tables

}

Now assume you have placed a Button on the Form and added an event handler for the Button's Click event. The implementation of this method simply places the TextBox's text in a message box:

protected void btnGetMultiLineText_Click (object sender, System.EventArgs e)

{

MessageBox.Show(multiLineBox.Text, "Here is your text");

}

Next, add some additional TextBoxes to the Form, this time focusing on the masking capabilities of the widget. The second TextBox (capsOnlyBox) forces all keystrokes to be converted to uppercase. The third TextBox (passwordBox) forces all keystrokes to be converted to a password character (which I have chosen to be "$," signifying how your financial life as a .NET developer should pan out).

An additional Button (btnPasswordDecoderRing) supports a Click event handler that extracts the real

C# and the .NET Platform, Second Edition keystrokes typed in the passwordBox TextBox widget, as shown here:

Apress © 2003 (1200 pages)

protected void btnPasswordDecoderRing_Click (object sender, System.EventArgs e)

This comprehensive text starts with a brief overview of the

{C# language and then quickly moves to key technical and

MessageBoxarchitectural.Show(passwordBoxissues for .NET .developersText, "Your. password is:");

}

Table of Contents

Here is the relevant code that configures these new TextBox types:

C# and the .NET Platform, Second Edition

Introduction

Part// OneThe- Introducing'Caps Only!'C# andwidgetthe .NET.Platform

Chapter// Note1 -thatThe PhilosophyCharacterCasingof .NET is established by an associated enumeration,

Chapter// which2 - Buildingcan beC#assignedApplicationsUpper, Lower, or Normal.

PartcapsOnlyBoxTwo - The C#.LocationProgramming= Languagenew System.Drawing.Point (14, 176);

capsOnlyBox.CharacterCasing = System.Windows.Forms.CharacterCasing.Upper;

Ch pter 3 - C# Language Fundamentals

capsOnlyBox.Size = new System.Drawing.Size (120, 20);

Chapter 4 - Object-Oriented Programming with C#

// The password TextBox

Chapter 5 - Exceptions and Object Lifetime

passwordBox.Location = new System.Drawing.Point (160, 176);

Chapter 6 - Interfaces and Collections

passwordBox.PasswordChar = '$';

Chapter 7 - Callback Interfaces, Delegates, and Events

Chapter

Part Five - Web Applications and XML Web Services

Figure 15-6: The many faces of the TextBox type

Chapter 18 - ASP.NET Web Pages and Web Controls

Chapter 19 - ASP.NET Web Applications

As mentioned, TextBoxBase has an additional derived type named RichTextBox. This class is a type that

Chapter 20 - XML Web Services

supports the display and manipulation of (highly) formatted text. For example, using this type you can

Index

configure support for multiple font selections, bulleted text, and so forth. I assume interested readers will Listconsultof Figuresonline help for further details.

List of Tables

SOURCE The TextBoxes application is included under the Chapter 15 subdirectory.

CODE

The MightyC#Buttonand the .TypeNET Platform, Second Edition

Of all user interface widgets, the Button can be regarded as the simplest, but most well-respected GUI input

Apress © 2003 (1200 pages)

device. The role of the System.Windows.Forms.Button type is to provide a simple vehicle for user input,

This comprehensive text starts with a brief overview of the

typically in responseC# languageto a mouseandclickthenorquicklykey pressmoves. Theto keyButtontechnicalclassandimmediately derives from an abstract type named ButtonBase,architecturalwhichissuesprovidesfor .NETa numberdevelopersof key. behaviors for all Button-related types (CheckBox, RadioButton, and Button). Table 15-4 describes some (but by no means all) of the core properties of ButtonBase.

Table of Contents

C# and the .NET Platform, Second Edition

Table 15-4: ButtonBase Properties

The Button class itself defines almost no additional functionality beyond that inherited by the ButtonBase

Part Five - Web Applications and XML Web Services

base class, with the key exception of the DialogResult property. As you will see later in this chapter, a dialog

Chapter 18 - ASP.NET Web Pages and Web Controls

box makes use of this property to return a value representing which Button was clicked (e.g., OK, Cancel,

Chapter 19 - ASP.NET Web Applications

and so on) when the dialog box is terminated.

Chapter 20 - XML Web Services

Index

Configuring the Content Position

List of Figures

List of Tables

Most people assume that the text contained in a Button is always placed on the middle of the Button, equidistant from all sides. While this can be a well-established standard, the TextAlign property of the ButtonBase type makes it extremely simple to position text at just about any location. To set the position of your Button's caption, use the System.Drawing.ContentAlignment enumeration (which happens to be the same enumeration used to configure the location of any optional Button image):

public enum System.Drawing.ContentAlignment

{

BottomCenter, BottomLeft,

BottomRight, MiddleCenter,

MiddleLeft, MiddleRight,

TopCenter, TopLeft,

TopRight

}

ISBN:1590590554

of the

technical and

Table

C# and

Part

Chapter

Chapter

Part

Chapter

Chapter

Chapter

Figure 15-7: The many faces of the Button type

Chapter 6 - Interfaces and Collections

Chapter 7 - Callback Interfaces, Delegates, and Events

ChapterSOURCE8 - AdvancedTheC# TypeButtonsConstructionapplicationTechis includediq es under the Chapter 15 directory.

Part ThreeCODE- Programming with .NET Assemblies

Chapter 9 - Understanding .NET Assemblies

Chapter 10 - Processes, AppDomains, Contexts, and Threads

Chapter 11 - Type Reflection, Late Binding, and Attribute-Based Programming

Part Four - Leveraging the .NET Libraries

Chapter 12 - Object Serialization and the .NET Remoting Layer

Chapter 13 - Building a Better Window (Introducing Windows Forms)

Chapter 14 - A Better Painting Framework (GDI+)

Chapter 15 - Programming with Windows Forms Controls

Chapter 16 - The System.IO Namespace

Chapter 17 - Data Access with ADO.NET

Part Five - Web Applications and XML Web Services

Chapter 18 - ASP.NET Web Pages and Web Controls

Chapter 19 - ASP.NET Web Applications

Chapter 20 - XML Web Services

Index

List of Figures

List of Tables

Working withC# andCheckBoxesthe .NET Platform, Second Edition

The other two ButtonBase-derived types of interest are CheckBox (which can support up to three possible

Apress © 2003 (1200 pages)

states) and RadioButton (which can be either selected or not selected). Like the Button, these types also

This comprehensive text starts with a brief overview of the

receive most of theirC# languagefunctionalityand fromthen thequicklyControlm vesbaseto keyclasstechnical. However,and each class defines some additional functionalityarchitectural. First, considerissues forthe.NETcored velpropertiess. of the CheckBox widget described in Table 15-5.

Table 15-5: CheckBox Properties

ChaptCheckStater 10 - Processes,GetsAppDomains,or sets valueContexts,indicatingand Threadswhether the CheckBox is checked, using a

Chapter 11 - Type Reflection,CheckStateLate Bienumeration,ding, nd Attributerather-thanB seda PrBooleangrammingvalue. This is very helpful

Part Four - Leveragingwhent.NETworkingLibrarieswith tristate CheckBoxes.

Part Five - Web Applications and XML Web Services

Chapter 18 - ASP.NET Web Pages and Web Controls

Chapter 19 - ASP.NET Web Applications

Chapter 20 - XML Web Services

Index

List of Figures

List of Tables

Working withC# andRadioButtonsthe .NET Platform,andSecondGroupBoxesEdition

The RadioButton type really requires little comment, given that it is (more or less) just a slightly redesigned

Apress © 2003 (1200 pages)

CheckBox. In fact, the members of a RadioButton are almost identical to those of the CheckBox type. The

This comprehensive text starts with a brief overview of the

only notable differenceC# languageis the CheckedChangedand th n quickly movesevent,to whichkey technicalis fired andwhen the Checked value changes. Also, the RadioButtonarchitecturaltype doesis uesnotforsupport.NET developersthe ThreeState. property, as a RadioButton must be on or off.

Typically, multiple RadioButton objects are logically and physically grouped together to function as a

Tablewholeof. CForntentsexample, if you have a set of four RadioButton types representing the color choice of a given

C#automobile,and the .NETyouPlatform,may wishSecondto ensureEditionthat only one of the four types can be checked at a time. Rather than

writing code programmatically to do so, use the GroupBox control. Like the RadioButton, there is little to

Introducti n

say about the GroupBox control, given that it receives all of its functionality from the Control base class.

Part One - Introducing C# and the .NET Platform

Chapter 1 - The Philosophy of .NET

ChapterFun 2with- BuildingRadioButtonsC# Applicatio (and CheckBoxes)

Part Two - The C# Programming Language

ChapterTo illustrate3 - C#workingLa uagewith Fundamentalsthe CheckBox, RadioButton, and GroupBox types, let's create a new Windows

Forms Application named CarConfig, which will be extended throughout this chapter. The main Form

Chapter 4 - Object-Oriented Programming with C#

allows users to enter in (and confirm) information about a new vehicle they intend to purchase. The order

Chapter 5 - Exceptions and Object Lifetime

summary is displayed in a Label type once the Confirm Order button has been clicked. Figure 15-8 shows

Chapter 6 - Interfaces and Collections

Part FiveFigure- Web15-Applicat8: The initialons andUI ofXMLtheWebCarConfigServicesForm

Chapter 18 - ASP.NET Web Pages and Web Controls

Chapter 19 - ASP.NET Web Applications

Assume you have initialized a number of private member variables representing each GUI widget. First,

Chapter 20 - XML Web Services

you have your CheckBox, constructed as shown here:

Index

List of Figures

// Create your CheckBox.

List of Tables

checkFloorMats.Location = new System.Drawing.Point (16, 16);

checkFloorMats.Text = "Extra Floor Mats";

checkFloorMats.Size = new System.Drawing.Size (136, 24);

checkFloorMats.FlatStyle = FlatStyle.Popup;

// Add to Control collection.

this.Controls.Add (this.checkFloorMats);

Programmatically speaking, when you wish to place a widget under the ownership of a related GroupBox, you want to add each item to the GroupBox's Controls collection (in the same way you add widgets to the Form's Controls collection). To make things a bit more interesting, respond to the Enter and Leave events sent by the GroupBox object as shown here:

// Yellow RadioButton.

radioYellow.Location = new System.Drawing.Point (96, 24);

radioYellow.Text = "Yellow";

radioYellow.Size = new System.Drawing.Size (64, 23);

C# and the .NET Platform, Second Edition

// Green, Red, and Pink RadioButtons configured in a similar vein.

Apress © 2003 (1200 pages)

// Now build the group of radio items.

This comprehensive text starts with a brief overview of the groupBox1.Location = new System.Drawing.Point (16, 56);

C# language and then quickly moves to key technical and groupBox1.Text = "Exterior Color";

architectural issues for .NET developers. groupBox1.Size = new System.Drawing.Size (264, 88);

groupBox1.Leave += new System.EventHandler (groupBox1_Leave);

groupBox1.Enter += new System.EventHandler (groupBox1_Enter);

Table of Contents

groupBox1.Controls.Add (this.radioPink);

C# and the .NET Platform, Second Edition groupBox1.Controls.Add (this.radioYellow);

Introduction

groupBox1.Controls.Add (this.radioRed);

Part One - Introducing C# and the .NET Platform

groupBox1.Controls.Add (this.radioGreen);

Chapter 1 - The Philosophy of .NET

Chapter 2 - Building C# Applications

Part Two - The C# Programming Language

ChaptUnderstand,3 - C#of Languagecourse, thatFundamentalsyou do not need to capture the Enter or Leave events for a GroupBox.

ChaptHowever,r 4 to- Objectillustrate,-Orientedthe eventProgramminghandlerswithupdateC# the caption text of the GroupBox as shown here:

Chapter 5 - Exceptions and Object Lifetime

Chapter 6 - Interfaces and Collections

// Figure out when the focus is in your group.

Chapter 7 - Callback Interfaces, Delegates, and(objectEv nts

protected void groupBox1_Leave sender, System.EventArgs e)

Chapter{ 8 - Advanced C# Type Construction Techniques

Part ThgroupBox1ee - Programming.Text with= "Exterior.NET AssembliesColor: Thanks for visiting the group...";

Chapter} 9 - Understanding .NET Assemblies

Chapterprotected10 - Processes,void groupBox1AppDomains,EnterContexts,(objectand Threadssender, System.EventArgs e)

{

Chapter 11 - Type Reflection, Late Binding, and Attribute-Based Programming

groupBox1.Text = "Exterior Color: You are in the group...";

Part Four - Leveraging the .NET Libraries

}

Chapter 12 - Object Serialization and the .NET Remoting Layer Chapter 13 - Building a Better Window (Introducing Windows Forms)

Chapter 14 - A Better Painting Framework (GDI+)

The final GUI widgets on this Form (the Label and Button types) also need to be configured and inserted in

Chapter 15 - Programming with Windows Forms Controls

the Form's Controls collection. The Label is used to display the order confirmation, which is formatted in

Chapter 16 - The System.IO Namespace

the Click event handler of the order Button, as shown here:

Chapter 17 - Data Access with ADO.NET

Part Five - Web Applications and XML Web Services

protected void btnOrder_Click (object sender, System.EventArgs e)

Chapter 18 - ASP.NET Web Pages and Web Controls

{

Chapter 19 - ASP.NET Web Applications

// Send this string to the Label.

infoLabel.Text = orderInfo;

}

Notice that both the CheckBox and RadioButton support the Checked property, which allows you to investigate the state of the widget. Recall that if you have configured a tristate CheckBox, you will need to check the state of the widget using the CheckState property.

ExaminingC#theandCheckedListBoxt .NET Platform, SecondControlEditi n

Now that you have explored the basic Button-centric widgets, let's move on to the set of list selection-

Apress © 2003 (1200 pages)

centric types, specifically, CheckedListBox, ListBox, and ComboBox. The CheckedListBox widget allows

This comprehensive text starts with a brief overview of the

you to group togetherC# languagerelated CheckBoxand then quicklyoptionsmovesin a scrollableto key technicallist controland . Assume you have added such a control to your CarConfigarchitecturalapplicationissues for .thatNETallowsdevelopersthe user. to configure a number of options for regarding the automobile's sound system (Figure 15-9).

Table of Contents

C# and

Part

Chapter

Chapter

Part

Chapter

Figure 15-9: The CheckedListBox type

Chapter 10 - Processes, AppDomains, Contexts, and Threads

Chapter 11 - Type Reflection, Late Binding, and Attribute-Based Programming

PartLikeFourthe -controlsLeveragingexaminedthe .NETthusLibrariesfar, the CheckedListBox type gains most of its functionality from the ChapterControl12base- ObjectclassSerializatitype. Also,ntheandCheckedListBox.NET Rem tingtypeLayerinherits additional functionality from its direct base

Chclass,pterListBox13 - Building(examinedBetterlaterWindowthis(Introducingchapter). Windows Forms)

Chapter 14 - A Better Painting Framework (GDI+)

To insert new items in a CheckedListBox, call Add() for each item or use the AddRange() method and

Chapter 15 - Programming with Windows Forms Controls

send in an array of objects (strings, to be exact) that represent the full set of checkable items. Here is the

Chapter 16 - The System.IO Namespace

configuration code (be sure to check out online help for details about these new properties):

Chapter 17 - Data Access with ADO.NET

Part Five - Web Applications and XML Web Services

// Configure the CheckedListBox.

Chapter 18 - ASP.NET Web Pages and Web Controls

checkedBoxRadioOptions.Location = new System.Drawing.Point (16, 48);

Chapter 19 - ASP.NET Web Applications

checkedBoxRadioOptions.Cursor = Cursors.Hand;

Chapter 20 - XML Web Services

checkedBoxRadioOptions.Size = new System.Drawing.Size (256, 64);

Index

checkedBoxRadioOptions.CheckOnClick = true;

List of Figures

// Add items to the CheckedListBox.

List of Tables

checkedBoxRadioOptions.Items.AddRange(new object[6] { "Front Speakers", "8-Track Tape Player",

"CD Player", "Cassette Player",

"Rear Speakers", "Ultra Base Thumper"} );

// As always, add the new widget to the Controls collection.

this.Controls.Add (this.checkedBoxRadioOptions);

Now update the logic behind the Click event for the Order Button. Ask the CheckedListBox which of its items are currently selected and add them to the orderInfo string. Here are the relevant code updates:

protected void btnOrder_Click (object sender, System.EventArgs e)

{

// Build a string to display information.

string orderInfo = "";

...

// For each item in the CheckedListBox:

C# and the .NET Platform, Second Edition

for(int i = 0; i < checkedBoxRadioOptions.Items.Count; i++)

if(checkedBoxRadioOptionsThis comprehensive text s arts with a brief overview of the

.GetItemChecked(i))

{C# language and then quickly moves to key technical and architectural issues for .NET developers.

//Get text of checked item and append to orderinfo string.

orderInfo += "Radio Item: ";

Table of Contents orderInfo += checkedBoxRadioOptions.Items[i].ToString();

orderInfo += "\n";

C# and the .NET Platform, Second Edition

}

Introduction

}

Part One - Introducing C# and the .NET Platform

...

Chapter 1 - The Philosophy of .NET

}

Chapter 2 - Building C# Applications

Part Two - The C# Programming Language

ChapterThe final3 note- C#regardingLanguagetheFundamentalsCheckedListBox type is that it supports the use of multiple columns through

Chapterthe inherited4 - ObjectMultiColumn-OrientedpropertyProg amming. Thus,withif youC#make the following update:

Chapter 5 - Exceptions and Object Lifetime

Chapter 6 - Interfaces and Collections

checkedBoxRadioOptions.MultiColumn = true;

ChaptercheckedBoxRadioOptions7 - Callback Interface , Delegates, and Events

.ColumnWidth = 130;

Chapter 8 - Advanced C# Type Construction Techniques

Part Three - Programming with .NET Assemblies

You see the multicolumn CheckedListBox shown in Figure 15-10.

Chapter 9 - Understanding .NET Assemblies

Chapter 10 - Processes, AppDomains, Contexts, and Threads

List of

Figure 15-10: Multicolumn CheckedListBox type

Like a ListBox, a ComboBox allows the user to make a selection from a well-defined set of possibilities.

C# and the .NET Platform, Second Edition

ComboBox derives from ListBox (which then derives from Control). To illustrate its use, add yet another

Apress © 2003 (1200 pages)

GUI widget to the CarConfig application that allows a user to enter the name of a preferred salesperson. If

This comprehensive text starts with a brief overview of the

the salesperson in question is not on the list, the user can enter a custom name. The GUI update is shown

C# language and then quickly moves to key technical and inFigure 15-12. architectural issues for .NET developers.

Table

C# and

Part

Chapter

Chapter

Part

ChapterFigure9 - 15Understanding-12: The ComboBox.NET Assembliestype

Chapter 10 - Processes, AppDomains, Contexts, and Threads

Chapter 11 - Type Reflection, Late Binding, and Attribute-Based Programming

This modification begins with configuring the ComboBox itself. As you can see here, the logic looks

Part Four - Leveraging the .NET Libraries

identical to that for the ListBox:

Chapter 12 - Object Serialization and the .NET Remoting Layer

Chapter 13 - Building a Better Window (Introducing Windows Forms)

// ComboBox configuration.

Chapter 14 - A Better Painting Framework (GDI+)

comboSalesPerson.Location = new System.Drawing.Point (152, 16);

Chapter 15 - Programming with Windows Forms Controls comboSalesPerson.Size = new System.Drawing.Size (128, 21);

Chapter 16 - The System.IO Namespace comboSalesPerson.Items.AddRange(new object[4]

Chapter 17 - Data Access with ADO.NET

{ "Baby Ry-Ry", "SPARK!", "Danny Boy",

Part Five - Web Applications and XML Web Services

"Karin 'Baby' Johnson"});

Chapter 18 - ASP.NET Web Pages and Web Controls this.Controls.Add (this.comboSalesPerson);

Chapter 19 - ASP.NET Web Applications

Chapter 20 - XML Web Services

IndexThe update to the btnOrder_Click() event handler is again simple, as shown here:

List of Figures

Listprotectedf Tables void btnOrder_Click (object sender, System.EventArgs e)

{

//Build a string to display information. string orderInfo = "";

...

//Use the Text property to figure out the user's salesperson.

if(comboSalesPerson.Text != "")

orderInfo += "Sales Person: " + comboSalesPerson.Text + "\n";

else

orderInfo += "You did not select a sales person!" + "\n";

...

}

The MonthCalendar# and the .NETControlPla form, Second Edition

The System.Windows.Forms namespace provides an extremely useful widget that allows the user to select a d

Apress © 2003 (1200 pages)

range of dates) using a friendly user interface: the MonthCalendar control. To showcase this new control, upda

This comprehensive text starts with a brief overview of the

existing CarConfigC#applicationlanguage andto allowthen thequicklyusermtoventers to keyin thet chnicalnew vehicle'sand delivery date. Figure 15-13 shows t updated (and slightlyarchitrearranged)ctural issuesFormfor ..NET developers.

Table

C# and

Part

Chapter

Chapter

Part

Chapter

Chapter

Chapter

Chapter

Chapter

Chapter

Part

Part

Figure 15-13: The MonthCalendar type

Chapter 12 - Object Serialization and the .NET Remoting Layer

Chapter 13 - Building a Better Window (Introducing Windows Forms)

ChapterTo begin14understanding- A Be ter Painthising newFrameworktype, examine(GDI+) the core MonthCalendar properties described in Table 15-6.

Chapter 15 - Programming with Windows Forms Controls

ChTablept r 156-6:- TheMonthCalendarSystem.IO NamesPropertiesace

Chapter 17 - Data Access with ADO.NET

Part Five - Web Applications and XML Web Services

Property

Chapter 18 - ASP.NET Web Pages and Web Controls

ChapterBoldedDates19 - ASP.NET Web ApplicationsThe array of DateTime objects that determine dates are shown in bold.

PartAlthoughOne - Introducingthe MonthCalendarC# and thecontrol.NEToffersPlatformfair bit of functionality, it is very simple to programmatically captur

Chaptrangerof1 dates- TheselectedPhilosophybyofthe.NETuser. The default behavior of this type is to always select (and circle) today's dat Chapterautomatically2 - Building. To obtainC# Applithe currentlyations selected date programmatically, you can update the Click event handler f

Paordert TwoButton,- The C#as shownPr gramminghere: Language

Chapter 3 - C# Language Fundamentals

Chapterprotected4 - Objectvoid-OrientedbtnOrderProgrammingClick with(objectC# sender, System.EventArgs e)

Chapter{ 5 - Exceptions and Object Lifetime

Chapter //6 -BuildInterfaces stringand Collectoi nsdisplay information.

string orderInfo = "";

Chapter 7 - Callback Interfaces, Delegates, and Events

...

Chapter 8 - Advanced C# Type Construction Techniques

// Get ship date.

Part Three - Programming with .NET Assemblies

DateTime d = monthCalendar.SelectionStart;

Chapter 9 - Understanding .NET Assemblies

string dateStr = string.Format("{0}/{1}/{2}", d.Month, d.Day, d.Year);

Chapter 10 - Processes, AppDomains, Contexts, and Threads

orderInfo += "Car will be sent: " + dateStr;

Chapter 11 - Type Reflection, Late Binding, and Attribute-Based Programming

...

Part Four - Leveraging the .NET Libraries

}

Chapter 12 - Object Serialization and the .NET Remoting Layer Chapter 13 - Building a Better Window (Introducing Windows Forms)

Chapter 14 - A Better Painting Framework (GDI+)

Notice that you can ask the MonthCalendar control for the currently selected date by using the SelectionStart p

Chapter 15 - Programming with Windows Forms Controls

This property returns a DateTime reference, which you store in a local variable. Using a handful of properties o ChapterDateTime16 -type,The youSystemcan.IOextractN mespaceout the information you need in a custom format. (Note that this type returns the

Chaptertime as17well,- DatawhichAccessyou arewithnotADOinterested.NET in.)

Part Five - Web Applications and XML Web Services

At this point I assume the user will specify exactly one day on which to deliver the new auto. However, what if yo

Chapter 18 - ASP.NET Web Pages and Web Controls

allow the user to select a range of possible shipping dates? In that case all the user needs to do is drag the cur

Chapter 19 - ASP.NET Web Applications

across the range of possible shipping dates (Figure 15-14).

Chapter 20 - XML Web Services Index

List of

List of

Figure 15-14: Selecting multiple dates

You already have seen that you can obtain the start of the selection using the SelectionStart property. The end selection can be determined using the SelectionEnd property. Here is the code update:

protected void btnOrder_Click (object sender, System.EventArgs e)

{

// Build a string to display information.

C# and the .NET Platform, Second Edition string orderInfo = "";

DateTime startD = monthCalendar.SelectionStart;

C# language and then quickly moves to key technical and

DateTime endD = monthCalendar.SelectionEnd; architectural issues for .NET developers.

string dateStartStr = string.Format("{0}/{1}/{2}", startD.Month, startD.Day

startD.Year);

string dateEndStr = string.Format("{0}/{1}/{2}", endD.Month, endD.Day, endD

Table of Contents

// The DateTime type supports overloaded operators!

C# and the .NET Platform, Second Edition if(dateStartStr != dateEndStr)

Introduction

{

Part One - Introducing C# and the .NET Platform

orderInfo += "Car will be sent between "

Chapter 1 - The Philosophy of .NET

+ dateStartStr + " and\n" + dateEndStr;

Chapter 2 - Building C# Applications

}

Part Two - The C# Programming Language

else // They picked a single date.

Chapter 3 - C# Language Fundamentals

orderInfo += "Car will be sent on " + dateStartStr;

Chapter 4 - Object-Oriented Programming with C#

...

Chapter 5 - Exceptions and Object Lifetime

}

Chapter 6 - Interfaces and Collections

Chapter 7 - Callback Interfaces, Delegates, and Events

Chapter 8 - Advanced C# Type Construction Techniques

Part Three - Programming with .NET Assemblies

Chapter 9 - Understanding .NET Assemblies

Chapter 10 - Processes, AppDomains, Contexts, and Threads

Chapter 11 - Type Reflection, Late Binding, and Attribute-Based Programming

Part Four - Leveraging the .NET Libraries

Chapter 12 - Object Serialization and the .NET Remoting Layer

Chapter 13 - Building a Better Window (Introducing Windows Forms)

Chapter 14 - A Better Painting Framework (GDI+)

Chapter 15 - Programming with Windows Forms Controls

Chapter 16 - The System.IO Namespace

Chapter 17 - Data Access with ADO.NET

Part Five - Web Applications and XML Web Services

Chapter 18 - ASP.NET Web Pages and Web Controls

Chapter 19 - ASP.NET Web Applications

Chapter 20 - XML Web Services

Index

List of Figures

List of Tables

More on theC#DateTimeand the .NET Platform,Type Second Edition

In the current example, you extracted a DateTime type from the MonthCalendar widget using the

Apress © 2003 (1200 pages)

SelectionStart and SelectionEnd properties. After this point, you used the Month, Day, and Year properties

This comprehensive text starts with a brief overview of the

to build a customC#formatlanguagestringand. Whilethenthisquicklyis permissible,moves to keyit istechnicalnot optimal,and given that the DateTime type has a number of builtarchitectural-in formattingissuesoptionsfor(.TableNET developers15-7). .

Table 15-7: DateTime Members

PartMinuteThr e - Programming with .NET Assemblies

Chapter 9 - Understanding .NET Assemblies

Second

Chapter 10 - Processes, AppDomains, Contexts, and Threads

Millisecond

Chapter 11 - Type Reflection, Late Binding, and Attribute-Based Programming

PartMaxValueFour - Leveraging the .NETRepresentLibrariesthe minimum and maximum DateTime value.

PartToLongDateString()Five - Web ApplicationsConvertand XMLtheWebcurrentS rvicesvalue of the DateTime type to a string representation.

Chapter 18 - ASP.NET Web Pages and Web Controls

ToLongTimeString()

Chapter 19 - ASP.NET Web Applications

ToShortDateString()

Chapter 20 - XML Web Services

ToShortTimeString()

Index

List of Figures

Using these members, you can replace the previous formatting you programmed by hand with the

List of Tables

following (you will see no change in the program's output):

string dateStartStr = startD.Date.ToShortDateString();

string dateEndStr = endD.Date.ToShortDateString();

Setting theC#Form'sand the .DefaultNET Platform,InputSecondButtonEdition

Many user input Forms (especially dialog boxes) have a particular Button that will automatically respond to

Apress © 2003 (1200 pages)

the user hitting the Enter key. For the CarConfig Form, if you wish to ensure that when the user hits the

This comprehensive text starts with a brief overview of the

Enter key, simplyC#makelanguageuse ofandthethenForm'squicklyAcceptButtonmoves to keyproperty:technical and architectural issues for .NET developers.

this.AcceptButton = this.btnOrder;

Table of Contents

C# and the .NET Platform, Second Edition

Introduction

Part One - Introducing C# and the .NET Platform

Chapter 1 - The Philosophy of .NET

Chapter 2 - Building C# Applications

Part Two - The C# Programming Language

Chapter 3 - C# Language Fundamentals

Chapter 4 - Object-Oriented Programming with C#

Chapter 5 - Exceptions and Object Lifetime

Chapter 6 - Interfaces and Collections

Chapter 7 - Callback Interfaces, Delegates, and Events

Chapter 8 - Advanced C# Type Construction Techniques

Part Three - Programming with .NET Assemblies

Chapter 9 - Understanding .NET Assemblies

Chapter 10 - Processes, AppDomains, Contexts, and Threads

Chapter 11 - Type Reflection, Late Binding, and Attribute-Based Programming

Part Four - Leveraging the .NET Libraries

Chapter 12 - Object Serialization and the .NET Remoting Layer

Chapter 13 - Building a Better Window (Introducing Windows Forms)

Chapter 14 - A Better Painting Framework (GDI+)

Chapter 15 - Programming with Windows Forms Controls

Chapter 16 - The System.IO Namespace

Chapter 17 - Data Access with ADO.NET

Part Five - Web Applications and XML Web Services

Chapter 18 - ASP.NET Web Pages and Web Controls

Chapter 19 - ASP.NET Web Applications

Chapter 20 - XML Web Services

Index

List of Figures

List of Tables

ConfiguringC#theand theTab.NETOrderPlatform, Second Edition

Next up, let's address the issue of tab order. As you know, when a Form or dialog box contains multiple

Apress © 2003 (1200 pages)

GUI widgets, users expect to be able to shift focus using the Tab key. Configuring the tab order for your set

This comprehensive text starts with a brief overview of the

of controls requiresC#thatlanguageyou understandand then quicklytwo keymovesproperties:to k y technicalTabStopandand TabIndex.

architectural issues for .NET developers.

The TabStop property can be set to true or false, based on whether or not you wish this GUI item to be reachable using the Tab key. Assuming the TabStop property has been set to true for a given widget, the

TableTabOrderof Contentsproperty is then set to establish its order of activation in the tabbing sequence (which is zero

C#based)and the. Consider.NET Platform,this example:Second Edition

Introduction

Part// OneConfigure- IntroducingtabbingC# and theproperties.NET Platform.

ChradioRedpter 1 -.TheTabIndexPhilosophy= of2;.NET

ChradioRedpter 2 -.BuildingTabStopC# =Applicationstrue;

Part Two - The C# Programming Language

Chapter 3 - C# Language Fundamentals

ChaptTherTab4 - ObjectOrder-OrientedWizardProgramming with C#

Chapter 5 - Exceptions and Object Lifetime

ChapterThe Visual6 -StudioInterfaces.NETandIDECollectionssupplies a Tab Order Wizard, accessed using the View | Tab Order menu

Chapterselection7 . Once- Callbactivated,k Interfaces,your Ddesilegates,n timeandFormEventsdisplays the current TabIndex value for each widget. To Chapterchange8these- Advalues,nc d C#clickTypeeachConstructionitem in theTechniquesorder you choose (Figure 15-15).

Part Three - Programming with .NET Assemblies

Index

List ofFigureFigur s15-15: The VS .NET Tab Order Wizard

List of Tables

To exit this Tab Order Wizard, simply hit the Esc key.

Assigning ToolTipsC# and the .NETto Platform,ControlsSecond Edition

To finish up the CarConfig Form, we have one final point of interest. Most modern user interfaces support

Apress © 2003 (1200 pages)

tool tips. In the System.Windows.Forms namespace, the ToolTip type represents this functionality. These

This comprehensive text starts with a brief overview of the

widgets are simplyC#smalllanguagefloatingandwindowsthen quicklythatmovesdisplaytoakeyhelpfultechnicalmessageand when the cursor hovers over a given item. Tablearchit15-8ecturaldescribesissuestheforcore.NETmembersdevelopersof.the ToolTip type.

Table 15-8: ToolTip Members

PartInitialDelayThree - ProgrammingThewithperiod.NETofAssembliestime (in milliseconds) that the cursor must remain stationary in Chapter 9 - Understandingthe ToolTip.NET Assregionmbliesbefore the ToolTip text is displayed. The default is equal to

Chapter 10 - Processes,theAppDomains,AutomaticDelayContexts,propertyand Threads.

type ToolTip. Next, configure the set of properties for the new item. Notice that you make a call to

Chapter 17 - Data Access with ADO.NET

SetToolTip(), which configures not only the text to be displayed, but also the widget to which it is assigned:

Part Five - Web Applications and XML Web Services

Chapter 18 - ASP.NET Web Pages and Web Controls

Chapter// Create19 - ASPand.NETassociateWeb Applicationstool tip to the calendar

calendarTip.Active = true;

Ch pt r 20 - XML Web Services

calendarTip.SetToolTip (monthCalendar,

Index

"Please select the date (or dates)\n when we can deliver your new car!");

List of Figures

List of Tables

Adding ToolTips at Design Time

If you wish to leverage the Visual Studio .NET IDE to build your tool tips, begin by adding a ToolTip widget to your Form using the Toolbox window. At this point, you can configure the ToolTip using the Properties window. To associate the new tip with a given widget, select the widget that should activate the tip and set the "ToolTip on" property (Figure 15-16).

Edition

ISBN:1590590554

brief overview of the

to key technical and

.

Table

C# and

Part

Chapter

Chapter

Part

Chapter

Figure 15-16: Associating a ToolTip to a given widget

Chapter 4 - Object-Oriented Programming with C#

Chapter 5 - Exceptions and Object Lifetime

SOURCE The CarConfig project is included under the Chapter 15 directory.

Chapter 6 - Interfaces and Collections

CODE

Chapter 7 - Callback Interfaces, Delegates, and Events

Chapter 8 - Advanced C# Type Construction Techniques

Part Three - Programming with .NET Assemblies

Chapter 9 - Understanding .NET Assemblies

Chapter 10 - Processes, AppDomains, Contexts, and Threads

Chapter 11 - Type Reflection, Late Binding, and Attribute-Based Programming

Part Four - Leveraging the .NET Libraries

Chapter 12 - Object Serialization and the .NET Remoting Layer

Chapter 13 - Building a Better Window (Introducing Windows Forms)

Chapter 14 - A Better Painting Framework (GDI+)

Chapter 15 - Programming with Windows Forms Controls

Chapter 16 - The System.IO Namespace

Chapter 17 - Data Access with ADO.NET

Part Five - Web Applications and XML Web Services

Chapter 18 - ASP.NET Web Pages and Web Controls

Chapter 19 - ASP.NET Web Applications

Chapter 20 - XML Web Services

Index

List of Figures

List of Tables

The TrackBarC# andControlthe .NET Platform, Second Edition

The TrackBar control allows users to select from a range of values, using a scroll bar-like input

Apress © 2003 (1200 pages)

mechanism. In many respects a TrackBar is functionally similar to a traditional scroll bar. When working

This comprehensive text starts with a brief overview of the

with this type, youC#needlanguageto set andthe minimumthen q icklyandmovesmaximumto keyrange,technicaltheandminimum and maximum change increments, and thearchistartingec urallocationissues forof .theNETslider'sdevelopersthumb. . Each of these aspects can be set using the properties described in Table 15-9.

Now you can build an application that makes use of three TrackBars. Each widget has an upper range of

Chapter 20 - XML Web Services

255 and a lower range of 0. As the user slides each thumb, the application intercepts the Scroll event and

Index

dynamically builds a new Color type based on the value of each slider. In this way, the user is able to view the underlying RGB value (and see the color) for a given selection. (Of course, the System.Windows.Forms namespace already provides a ColorDialog type for this purpose.)

First you need to configure each TrackBar. Assume your Form contains three private TrackBar member variables (redTrackBar, greenTrackBar, and blueTrackBar). Here is the relevant code for blueTrackBar (the remaining bars look almost identical, with the exception of the name of the Scroll event handler):

// Here is the blue TrackBar.

blueTrackBar.TickFrequency = 5;

blueTrackBar.Location = new System.Drawing.Point (104, 200);

blueTrackBar.TickStyle = System.Windows.Forms.TickStyle.TopLeft;

blueTrackBar.Maximum = 255;

blueTrackBar.Scroll += new System.EventHandler (this.blueTrackBar_Scroll);

Note that the default minimum value of the TrackBar is 0 and thus does not need to be explicitly set. In the event handlers for each TrackBar, you make a call to an internal private helper function named

UpdateColor(), which does the real grunt work, as shown here:

C# and the .NET Platform, Second Edition

protected void blueTrackBar_Scroll (object sender, System.EventArgs e)

Apress © 2003 (1200 pages)

{

This comprehensive text starts with a brief overview of the

UpdateColor();

C# language and then quickly moves to key technical and

}architectural issues for .NET developers.

UpdateColor() is responsible for two major tasks. First you read the current value of each TrackBar and

Table of Contents

send this state data to a new Color variable (using the FromArgb() member). Once you have the newly

C# and the .NET Platform, Second Edition

configured color, you update a Form-level member variable of type PictureBox (named colorBox), which in

Introduction

this case does not hold an actual bitmap image, but simply maintains the current background color.

Part One - Introducing C# and the .NET Platform

Finally, the UpdateColor() method formats this information in a string placed on the Form's color display

Chapter 1 - The Philosophy of .NET label (lblCurrColor), as shown here:

Chapter 2 - Building C# Applications

Part Two - The C# Programming Language

private void UpdateColor()

Chapter 3 - C# Language Fundamentals

{

Chapter 4 - Object-Oriented Programming with C# Chapter 5 - Exceptions and Object Lifetime Chapter 6 - Interfaces and Collections

Chapter 7 - Callback Interfaces, Delegates, and Events

Chapter 8 - Advanced C# Type Construction Techniques

colorBox.BackColor = c;

Part Three - Programming with .NET Assemblies

// Set color label.

Chapter 9 - Understanding .NET Assemblies lblCurrColor.Text =

Chapter 10 - Processes, AppDomains, Contexts, and Threads string.Format("Current color is: ({0}, {1}, {2})",

Chapter 11 - Type Reflection, Late Binding, and Attribute-Based Programming

redTrackBar.Value, greenTrackBar.Value,

Part Four - Leveraging the .NET Libraries

blueTrackBar.Value);

Chapter 12 - Object Serialization and the .NET Remoting Layer

}

Chapter 13 - Building a Better Window (Introducing Windows Forms)

Chapter 14 - A Better Painting Framework (GDI+)

The final detail is to set the initial values of each slider when the Form comes to life and render the current

Chapter 15 - Programming with Windows Forms Controls

color, as shown here:

Chapter 16 - The System.IO Namespace Chapter 17 - Data Access with ADO.NET

public TrackForm()

Part Five - Web Applications and XML Web Services

{

Chapter 18 - ASP.NET Web Pages and Web Controls

InitializeComponent();

Chapter 19 - ASP.NET Web Applications

CenterToScreen();

Chapter 20 - XML Web Services

Index // Set initial position of each slider.

redTrackBar.Value = 100;

List of Figures

greenTrackBar.Value = 255;

List of Tables

blueTrackBar.Value = 0;

UpdateColor();

}