Summary C# and the .NET Platform, Second Edition

by Andrew Troelsen ISBN:1590590554

In this chapter, you examined how to configure distinct .NET assemblies to share types between

Apress © 2003 (1200 pages)

application boundaries. As you have seen, a remote object may be configured as an MBV or MBR type.

This comprehensive text starts with a brief overview of the

This choice ultimatelyC# languagecontrolsandhowthena remotequicklytypemovesis realizedto key technicalin the client'sand application domain (a copy or transparent proxy)architectural. Given thisissuesdistinction,for .NETthedeveloperschapter opened. by examining the MBV-centric topic of object serialization.

TableIf youofhaveContentsconfigured a type to function as an MBR entity, you are suddenly faced with a number of C#relatedand thechoices.NET Platform,(WKO vsSecond. CAO, Editionsingle call vs. singleton, and so forth), each of which was addressed

during this chapter. As well, you also examined the process of tracking the lifetime of a remote object via

Introduction

the use of leases and lease sponsorship. Finally, you revisited the role of the .NET delegate type in order

Part One - Introducing C# and the .NET Platform

to understand how to asynchronously invoke a remote method (which, as luck would have it, is identical to

Chapter 1 - The Philosophy of .NET

the process of asynchronously invoking a local type).

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

Chapter C#13:andBuildingthe .NET Platform,a SecondBetterEditionWindow (Introducing

This comprehensive text starts with a brief overview of the

C# language and then quickly moves to key technical and

If you have read through the previous chapters, you should have a solid handle on the C# programming

architectural issues for .NET developers.

language as well as the foundation of the .NET architecture. While you could take your newfound knowledge and begin building the next generation of console applications (boring!) you are more likely to

be interested in building an attractive graphical user interface (GUI) to allow the outside world to interact

Table of Contents with your system.

C# and the .NET Platform, Second Edition

Introduction

This chapter introduces you to the System.Windows.Forms namespace. Here, you learn how to build a ParthighlyOnestylized- IntroducimaingwindowC# and(ethe.g..,NETa FormPlatform-derived class). In the process, you learn about a number of Chapterwindow1-related- The types,Philosophyincludingof .NETMenuItem, ToolBar, StatusBar, and Application. This chapter also

Chapterintroduces2 -howBuildingto captureC# Applicationsand respond to user input (i.e., handling mouse and keyboard events) within the

PartcontextTwo of- Thea GUIC# environmentProgrammi g. AlongLanguagethe way, you will construct a final example that illustrates the

Chapterconstruction3 - C#of MDILanguageapplicationsFundamentalsla Windows Forms.

Chapter 4 - Object-Oriented Programming with C#

ChapterA Tale5 -ofExceptionsThreeandGUIObjectNamespacesLifetime

Chapter 6 - Interfaces and Collections

ChapterThe .NET7 -platformCallback(asInterfaceof version, Delegates,1.1) providesand Eventsthree GUI toolkits, known as "Windows Forms," "Web

Forms," and "Mobile Forms." The System.Windows.Forms namespaces contain a number of types that

Chapter 8 - Advanced C# Type Construction Techniques

allow you to build traditional desktop applications, as well as Windows-based applications that target

Part Three - Programming with .NET Assemblies

handled computing devices (such as the Pocket PC). As you would expect, Windows Forms hides the raw

Chapter 9 - Understanding .NET Assemblies

windowing primitives from view, allowing you to focus on the functionality of your application using the

Chapter 10 - Processes, AppDomains, Contexts, and Threads

familiar .NET type system.

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

Part Four - Leveraging the .NET Libraries

Web Forms, on the other hand, is a GUI toolkit used during ASP.NET development. The bulk of the Web

Chapter 12 - Object Serialization and the .NET Remoting Layer

Form types are contained in the System.Web.UI.WebControls namespace. Using these types, you are

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

able to build browser-independent front ends based on various industry standards (HTML, HTTP, and so

Chapter 14 - A Better Painting Framework (GDI+)

forth). You will get to know the ASP.NET Web controls in Chapter 18.

Chapter 15 - Programming with Windows Forms Controls

Finally, .NET version 1.1 ships with a new GUI-centric namespace, System.Web.UI.MobileControls, which

Chapter 16 - The System.IO Namespace

allow you to build UIs that target mobile devices (such as cellular phones). Not surprisingly, the

Chapter 17 - Data Access with ADO.NET

programming model of Mobile control applications mimics the functionality found within ASP.NET.

Part Five - Web Applications and XML Web Services

Chapter 18 - ASP.NET Web Pages and Web Controls

Note Coverage of mobile .NET technologies (including Pocket PC programming) is outside the scope

Chapter 19 - ASP.NET Web Applications

of this text. If you are interested, check out Mobile .NET (Ferguson, Apress 2001).

Chapter 20 - XML Web Services

IndexIt is worth pointing out that while Windows Forms, Web Forms, and Mobile Forms technologies define a

Listnumberof Figuresof similarly named types (e.g., Button, CheckBox, etc.) with similar members (Text, BackColor, Listetcof.),Tablesthey do not share a common implementation and cannot be treated identically. Nevertheless, as you become comfortable with the Windows Forms namespace, you should find the process of learning the details of other .NET GUI toolkits far more palatable.

Overview ofC#theandSystemthe .NET Platform,.WindowsSecond.FormsEdition Namespace

Like any namespace, System.Windows.Forms is composed of a number of classes, structures, delegates,

Apress © 2003 (1200 pages)

interfaces, and enumerations. Over the next couple of chapters, you drill into the specifics of a good

This comprehensive text starts with a brief overview of the

number of these C#typeslanguage. Whileandit is redundantthen quicklytomoveslist everyto keymembertechnicalof theandWindows Forms family (as they are all documentedarchitecturalin online Help)issuesTablefor .NET13-developers1 lists some. (but by no means all) of the core classes found within System.Windows.Forms.

Table of Contents

Table 13-1: A Subset of Types Within the System.Windows.Forms Namespace

command window looming in the background. This is because you have not yet configured the build

the Project Properties window (just right-click the project icon from the Solution Explorer) and expand the

Apress © 2003 (1200 pages)

"Common Properties | General" node. Finally, configure the "Output Type" property as "Windows

This comprehensive text starts withthea brief overview of the

Application" (Figure 13-3). When you recompile, annoying command window will be gone and your

C# language and then quickly moves to key technical and application will run as a true-blue Windows app.

architectural issues for .NET developers.

Table

C# and

Part

Chapter

Chapter

Part

Chapter

Chapter

Chapter

Chapter

Chapter

Chapter

Part Three - Programming with .NET Assemblies

Figure 13-3: Specifying /t—winexe within VS .NET

Chapter 9 - Understanding .NET Assemblies

Chapter 10 - Processes, AppDomains, Contexts, and Threads

So, at this point we have a minimizable, maximizable, resizable, and closable main window (with a default

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

system-supplied icon to boot!). To be sure, it is a great boon to the Win32 programmers of the world to PartforegoFourthe- Leveragingneed to manuallythe .NETconfigureLibraries a WndProc function, establish a WinMain() entry point, and twiddle Chapterthe bits12of -aObjectWNDCLASSEXSerializationstructureand the. .Granted,NET Remotingyour MainWindowLayer does not do too much at this point,

Chowever,apt r 13you'll- Buildienhanceg B tterits functionalityWind w (IntroducingthroughoutWindowsthe chapterForms).

Chapter 14 - A Better Painting Framework (GDI+)

SOURCE The MyRawWindow application can be found under the Chapter 13 subdirectory.

Chapter 15 - Programming with Windows Forms Controls

CODE

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

Building a VSC# and.NETthe .NETWindowsPlatform, SecondFormsEditionProject Workspace

The benefit of building Windows Forms applications using Visual Studio .NET is that the integrated tools

Apress © 2003 (1200 pages)

can take care of a number of mundane coding details by delegating them to a number of wizards,

This comprehensive text starts with a brief overview of the

configuration windows,C# languageand soandforththen. Toquicklyillustratemoveshowtotokeymaketechnicaluse ofandsuch assistance, close your current workspace. Now,architecturalselect a newissuesC# Windowsfor .NET developersApplication. project type (see Figure 13-4).

Table

C# and

Part

Chapter

Chapter

Part

Chapter

Chapter

Chapter

Chapter

Chapter

Chapter

Figure 13-4: The Windows Forms project workspace

Part Three - Programming with .NET Assemblies

Chapter 9 - Understanding .NET Assemblies

When you click OK, you will find that you are automatically given a new class derived from

Chapter 10 - Processes, AppDomains, Contexts, and Threads

System.Windows.Forms.Form [with a properly configured Main() method] and have references set to each

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

required assembly (as well as some additional assemblies that you may or may not make use of).

Part Four - Leveraging the .NET Libraries

ChapterYou will12also- Objectsee thatSerializationyou are givenand thea design.NET Re-timeotingtemplateLayer that can be used to assemble the user

interface of your Form (Figure 13-5). Understand that as you update this design-time template, you are

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

indirectly adding code to the associated Form-derived class (named Form1 by default).

Chapter 14 - A Better Painting Framework (GDI+)

Chapter 15 - Programming with Windows Forms Controls

Chapter

Chapter

Figure 13-5: The Form Designer

Using the Solution Explorer window, you are able to alternate between this design-time template and the underlying C# code. To view the code that represents your current design, simply right-click the *.cs file and select "View Code". You can also open the code window by double-clicking anywhere on the design time Form; however, this has the (possibly undesirable) effect of writing an event handler for the Form's Load event (more on event processing later in this chapter).

Once you open the code window, you will see a class that looks very much like the following (XML-based code comments removed for clarity):

namespace VSWinApp

C# and the .NET Platform, Second Edition

{

by Andrew Troelsen ISBN:1590590554 public class Form1 : System.Windows.Forms.Form

{Apress © 2003 (1200 pages)

This comprehensive text starts with a brief overview of the

private System.ComponentModel.Container components = null;

C# language and then quickly moves to key technical and public Form1()

architectural issues for .NET developers.

{ InitializeComponent(); }

protected override void Dispose( bool disposing )

{

Table of Contents

if( disposing )

C# and the .NET Platform, Second Edition

{

Introduction

if (components != null)

Part One - Introducing C# and the .NET Platform

{

Chapter 1 - The Philosophy of .NET components.Dispose();

Chapter 2 - Building C# Applications

}

Part Two - The C# Programming Language

}

Chapter 3 - C# Language Fundamentals

base.Dispose(disposing);

Chapter 4 - Object-Oriented Programming with C#

}

Chapter 5 - Exceptions and Object Lifetime

#region Windows Form Designer generated code

Chapter 6 - Inteprivatefaces and Collections

void InitializeComponent()

Chapter 7 - Callback{ Interfaces, Delegates, and Events

Chapter 8 - AdvancedthisC# Type.componentsConstruc ion=Techniquesnew System.ComponentModel.Container();

Part Three - Programmingthiswith.Size.NET =Assembliesnew System.Drawing.Size(300,300);

Chapter 9 - Understandingthis.NETTextAssemblies= "Form1";

}

Chapter 10 - Processes, AppDomains, Contexts, and Threads

#endregion

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

[STAThread]

Part Four - Leveraging the .NET Libraries

static void Main()

Chapter 12 - Object Serialization and the .NET Remoting Layer

{

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

Application.Run(new Form1());

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

As you can see, this class listing is essentially the same code as the previous raw Windows Forms Chapterexample19. Your- ASPtype.NETstillWebderivesApplicatifromnsSystem.Windows.Forms.Form, and the Main() method still calls

ChaApplicationter 20 -.Run()XML Web. TheServicesmajor change is a new method named InitializeComponent(), which is wrapped by

Indthex#region and #endregion preprocessor directives (as described in Chapter 2).

List of Figures

ListTheof TablesRole of InitializeComponent() and Dispose()

The InitializeComponent() method is updated automatically by the Form Designer to reflect the modifications you make to the Form and its controls using the Visual Studio .NET IDE. For example, if you were to use the Properties window to modify the Form's Text and BackColor properties (Figure 13-6), you would find that InitializeComponent() has been modified accordingly:

Edition

ISBN:1590590554

brief overview of the

to key technical and

.

Table

C# and

Part

Chapter

Chapter

Part

Chapter

Figure 13-6: The Properties window provides design time editing support.

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

Chapter 6 - Interfaces and Collections

#region Windows Form Designer generated code

Chapter 7 - Callback Interfaces, Delegates, and Events private void InitializeComponent()

Chapter 8 - Advanced C# Type Construction Techniques

{

Part Three - Programming with .NET Assemblies

this.AutoScaleBaseSize = new System.Drawing.Size(5, 13);

Chapter 9 - Understanding .NET Assemblies

this.BackColor = System.Drawing.Color.Lime;

Chapter 10 - Processes, AppDomains, Contexts, and Threads this.ClientSize = new System.Drawing.Size(292, 273);

Chapter 11 - Type Reflection, Late Binding, and Attribute-Based Programming this.Text = "My Rad Form";

Part Four - Leveraging the .NET Libraries

}

Chapter 12 - Object Serialization and the .NET Remoting Layer

#endregion

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

Chapter 14 - A Better Painting Framework (GDI+)

The Form-derived class calls InitializeComponent() within the scope of the default constructor:

Chapter 15 - Programming with Windows Forms Controls

Chapter 16 - The System.IO Namespace

Chapterpublic17Form1()- Data Access with ADO.NET

Part{ Five - Web Applications and XML Web Services

// Required for Windows Form Designer support

Chapter 18 - ASP.NET Web Pages and Web Controls

InitializeComponent();

Chapter 19 - ASP.NET Web Applications

}

Chapter 20 - XML Web Services

Index

List of Figures

Do be very aware that this helper method is simply a well-known member that VS .NET understands. If

List of Tables

you moved all the code within this method into the Form's constructor, your application would run identically. Unlike other windowing toolkits, the wizard-generated code does not tie you to a particular IDE (VS .NET or otherwise).

The final point of interest is the overridden Dispose() method. This method is called automatically when your Form is about to be destroyed, and is a safe place to free any allocated resources.

The SystemC#.Windowsand the .NET.FormsPlatform,.ApplicationSecond Edi ion Class

The Application class defines members that allow you to control various low-level behaviors of a Windows

Apress © 2003 (1200 pages)

Forms application. For example, the Application class defines a set of events that allow you to respond to

This comprehensive text starts with a brief overview of the

events such as applicationC# languageshutdownand thenandquicklyidle processingm ves to key. Fortechnicalthe mostandpart, you do not need to directly interact with this typearchitectural(beyondissuescallingforRun().NETtodevelopersshow your. main window); however, let's check out some of its behavior. To begin, ponder the following core methods (all of which are static) listed in Table 13-2.

PartExit()Three - Programming with .NETTerminatesAssembliesthe application.

ChapterThe Application17 - DataclassAccessalsowithdefinesADO.NETa number of static properties, many of which are read-only. As you

PartexamineFive -theW bfollowingAppl cationstable,andrealizeXML Webthat eachServicesproperty represents some "application-level" trait such as Chaptercompany18 name,- ASP.NETversionWebnumber,Pages andandWebsoCforthntrols. In fact, given what you already know about .NET attributes

(seeChapter 11), many of these properties should look vaguely familiar (Table 13-3).

Chapter 19 - ASP.NET Web Applications

Chapter 20 - XML Web Services

Table 13-3: Core Properties of the Application Type

Index

List of Figures

List of Tables

Notice that some properties, such as CompanyName and ProductName, provide a handy way to retrieve

Chapter 8 - Advanced C# Type Construction Techniques

assembly-level metadata. As you recall from Chapter 11, an assembly may be described using a number

Part Three - Programming with .NET Assemblies

of attributes. Thus, if you specify a value for the AssemblyCompany attribute, you may obtain this

Chapter 9 - Understanding .NET Assemblies

information using Application.CompanyName without the making direct use of the types defined within

Chapter 10 - Processes, AppDomains, Contexts, and Threads

System.Reflection.

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

Part Four - Leveraging the .NET Libraries

Finally, the Application class defines the events shown in Table 13-4.

Chapter 12 - Object Serialization and the .NET Remoting Layer

Fun with the Application Class

To illustrate some of the functionality of the Application class (as well as preview Windows Forms event handling), let's enhance our current raw MainWindow to perform the following tasks:

Display some basic information about this application on startup.

Respond to the ApplicationExit event.

Perform some preprocessing of the WM_LBUTTONDOWN message.

To begin, assume that you have extended your manifest using a number of attributes that mark the name of this fine application and the company that created it. Thus, insert a new file named assemblyinfo.cs which contains the following assembly-level attributes:

[assembly:AssemblyCompany("Intertech, Inc.")]

Apress © 2003 (1200 pages)

[assembly:AssemblyProduct("A Better Window")]

This comprehensive text starts with a brief overview of the

C# language and then quickly moves to key technical and

architectural issues for .NET developers.

The constructor of our Form-derived class can obtain this information using properties of the Application, which are displayed using the Show() method of the MessageBox type:

Table of Contents

using System;

C# and the .NET Platform, Second Edition

using System.Windows.Forms;

Introduction

Part One - Introducing C# and the .NET Platform

namespace AppClassExample

Chapter 1 - The Philosophy of .NET

{

Chapter 2 - Building C# Applications

public class MainForm : Form

Part Two{- The C# Programming Language

Chapter 3 - C# Language Fundamentals

...

Chapter 4 - Object-Oriented Programming with C# public MainForm()

Chapter 5 - Exceptions and Object Lifetime

{ GetStats(); }

Chapter 6 - Inteprivatefaces and Collections

void GetStats()

Chapter 7 - Callback{ Interfaces, Delegates, and Events

Chapter 8 - Advanced//C#ReadType Constructionsome metadataTechniquesfrom the manifest.

Part Three - Programmingstringwith .NETinfoAssemblies= string.Format("Company: {0}\n",

Chapter 9 - Understanding .NETApplicationAssemblies .CompanyName);

info += string.Format("App Name: {0}\n",

Chapter 10 - Processes, AppDomains, Contexts, and Threads

Application.ProductName);

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

info += string.Format("I live here: {0}",

Part Four - Leveraging the .NET Libraries

Application.StartupPath);

Chapter 12 - Object Serialization and the .NET Remoting Layer

MessageBox.Show(info);

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

When you run this application, you see a message box that displays various bits of information (Figure 13-

Chapter 18 - ASP.NET Web Pages and Web Controls

7).

Chapter 19 - ASP.NET Web Applications

Chapter 20 - XML Web Services

Index

List of

List of

Figure 13-7: Reading attributes via the Application type

Responding to the ApplicationExit Event

Next, let's configure this Form to respond to the ApplicationExit event. When you wish to respond to events from within a Windows Forms application, you will be happy to find that the same event logic detailed in Chapter 7 is used to handle GUI-based events. Therefore, if you wish to intercept the ApplicationExit event, you simply register an event handler using the += operator:

public class MainForm : Form

{

...

public MainForm()

{

C# and the .NET Platform, Second Edition

...

by Andrew Troelsen ISBN:1590590554

// Intercept the ApplicationExit event.

Apress © 2003 (1200 pages)

Application.ApplicationExit += new EventHandler(Form_OnExit);

}This comprehensive text starts with a brief overview of the C# language and then quickly moves to key technical and

//Event handler.

architectural issues for .NET developers.

private void Form_OnExit(object sender, EventArgs evArgs)

{

MessageBox.Show("See ya!", "This app is dead...");

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

Notice that the signature of the ApplicationExit event handler must conform to a delegate of type

ChaptSystemr 2 - Building C# Applications

.EventHandler:

Part Two - The C# Programming Language

Chapter 3 - C# Language Fundamentals

// Many GUI-based events make use of this delegate (EventHandler)

Chapter 4 - Object-Oriented Programming with C#

// which requires two parameters:

Chapter 5 - Exceptions and Object Lifetime

public delegate void EventHandler(object sender, EventArgs e);

Chapter 6 - Interfaces and Collections

Chapter 7 - Callback Interfaces, Delegates, and Events

As you will see, the EventHandler delegate is the most common type used to handle events under

Chapter 8 - Advanced C# Type Construction Techniques

Windows Forms, however, alternatives do exist for other events. The first parameter of the EventHandler

Part Three - Programming with .NET Assemblies

delegate is of type System.Object, which represents the object sending the event. The EventArgs

Chapter 9 - Understanding .NET Assemblies

parameter (or a descendent thereof) contains relevant information for the current event.

Chapter 10 - Processes, AppDomains, Contexts, and Threads

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

While the EventArgs parameter will always work in conjunction with the EventHandler delegate, it also

Part Four - Leveraging the .NET Libraries

functions as the base class to more specific event argument types. For example, if you have an event

Chapter 12 - Object Serialization and the .NET Remoting Layer

handler that responds to a mouse event, the MouseEventArgs parameter will contain mouse related

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

details such as the (x,y) position of the cursor. Keyboard event handlers make use of the KeyEventArgs

Chapter 14 - A Better Painting Framework (GDI+)

type. In any case, if you run the application, you will be able to respond to the termination of this

Chapter 15 - Programming with Windows Forms Controls application.

Chapter 16 - The System.IO Namespace

Chapter 17 - Data Access with ADO.NET

Preprocessing Messages with the Application Class

Part Five - Web Applications and XML Web Services

Chapter 18 - ASP.NET Web Pages and Web Controls

The final step of this example is to perform some preprocessing logic of the WM_LBUTTONDOWN

Chapter 19 - ASP.NET Web Applications

message. As you may know, this standard Windows message is sent when the left mouse button has Chapterbeen clicked20 - XMLwithinWebtheServicesclient area of a given Form (or any GUI widget that is equipped to respond to this

Indevent)x . Now, be very aware that you will find a much simpler way to intercept standard mouse events a bit

Listlaterof inFiguresthis chapter. The point of this step is simply to illustrate how to perform custom preprocessing logic Listbeforeof Tablesa given event is fully dispatched to its handler.

When you wish to filter messages in the .NET framework, your first task is to create a new class that implements the IMessageFilter interface. This is extremely simple, given that IMessageFilter defines only one method, PreFilterMessage(). Return "true" to filter the message and prevent it from being dispatched or "false" to allow the message to continue on its way.

Within the scope of your implementation, you may examine the incoming Message.Msg field to extract the numerical value of the Windows message (in this case, WM_LBUTTONDOWN, which is the value 513). For example:

using Microsoft.Win32; // Contains Win32 specific types.

...

// Create a message filter.

public class MyMessageFilter : IMessageFilter

{

public bool PreFilterMessage(ref Message m)

C# and the .NET Platform, Second Edition

{

{ This comprehensive text starts with a brief overview of the

C# language and then quickly moves to key technical and

MessageBox.Show("WM_LBUTTONDOWN is: " + m.Msg); architectural issues for .NET developers.

return true;

}

return false; // All other messages are ignored...

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

Once you have created the class that will be filtering the incoming messages, you must register a new

Chapter 2 - Building C# Applications

instance of this type using the static AddMessageFilter() method. Here is the update to your existing

PartMainFormTwo - Theclass:C# Programming Language

Chapter 3 - C# Language Fundamentals

Chapter 4 - Object-Oriented Programming with C# public class MainForm : Form

Chapter 5 - Exceptions and Object Lifetime

{

Chapter 6 - Interfaces and Collections

private MyMessageFilter msgFilter = new MyMessageFilter();

Chapter 7 - Callback Interfaces, Delegates, and Events

...

Chapter public8 - AdvancedMainForm()C# Type Construction Techniques

Part Three{ - Programming with .NET Assemblies

Chapter 9 - Understanding... .NET Assemblies

Chapter 10 - Processes,// Add AppDomains,message filterCon xts,. and Threads

Application.AddMessageFilter(msgFilter);

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

}

Part Four - Leveraging the .NET Libraries

// Event handler

Chapter 12 - Object Serialization and the .NET Remoting Layer

private void Form_OnExit(object sender, EventArgs evArgs)

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

{

Chapter 14 - A Better Painting Framework (GDI+)

MessageBox.Show("See ya!", "This app is dead...");

Chapter 15 - Programming with Windows Forms Controls

// Remove message filter.

Chapter 16 - The System.IO Namespace

Application.RemoveMessageFilter(msgFilter);

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

IndexWhen you run this application, you see a message that informs you of the numerical value of the Win32

ListWMof_FiguresLBUTTONDOWN message when you click the left mouse button anywhere in the application.

List of Tables

As you can tell, filtering messages is not a task you need to perform all that often (if ever). Nevertheless, it is nice to know that Windows Forms allows you to drop down to this level of detail if you so choose.

SOURCE The AppClassExample project can be found under the Chapter 13 subdirectory.

CODE

The AnatomyC# andof thea Form.NET Platform, Second Edition

Now that you understand the role of the Application type, our next task is to examine the functionality of the

Apress © 2003 (1200 pages)

Form class itself. As you have seen, when you create a new window (or dialog box) you need to define a

This comprehensive text starts with a brief overview of the

new class derivingC#fromlanguageSystemand.Windowsthen quickly.Formsoves.Formto.keyThistechnicalclass gainsa d a great deal of functionality from the types in its inheritancearchite turalchainissues. Figurefor .NET13-8developersillustrates.the big picture.

Table

C# and

Part

Chapter

Chapter

Part

Chapter

Chapter

Chapter

Chapter

Chapter

Chapter

Part ThreeFigure- Programming13-8: The derivationwith .NETofAssembliesa custom Form

Chapter 9 - Understanding .NET Assemblies

Before we get to the real meat of the Form's inheritance chain, understand that like any type in the .NET

Chapter 10 - Processes, AppDomains, Contexts, and Threads

universe, Form ultimately derives from System.Object (which should be no surprise to you at this point). As

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

you recall from Chapter 12,MarshalByRefObject defines the behavior to remote this type by reference,

Part Four - Leveraging the .NET Libraries

rather than by value. Thus, if you remotely interact with a Form across the wire, you are manipulating a

Chapter 12 - Object Serialization and the .NET Remoting Layer

reference to the Form on the remote machine (not a local copy of the Form on the client machine).

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

Chapter 14 - A Better Painting Framework (GDI+)

Detailing each and every member of each class in the Form's inheritance chain would require a small

Chapter 15 - Programming with Windows Forms Controls

book in itself. However, it is important to understand the core behavior supplied by each base class. I Chapterassume16that- TheyouSystemwill spend.IO Natimespaceexamining the full details behind each class at your leisure.

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 ComponentC# a d theClass.NET Platform, Second Edition

The first base class of immediate interest is Component. The Component type provides a canned

Apress © 2003 (1200 pages)

implementation of the IComponent interface. This predefined interface defines a property named Site,

This comprehensive text starts with a brief overview of the

which returns (surprise,C# languagesurprise)and anthenISitequicklyinterfacemoves. Furthermore,to key technicalIComponentand inherits a single event from the IDisposable interfacearchitecturnamedl issuesDisposed:for .NET developers.

public interface IComponent : IDisposable

Table of Contents

{

C# and the .NET Platform, Second Edition

// The Site property.

Introduction

public ISite Site { get; set; }

Part One - Introducing C# and the .NET Platform

// The Disposed event.

Chapter 1 - The Philosophy of .NET

public event EventHandler Disposed;

Chapter 2 - Building C# Applications

}

Part Two - The C# Programming Language

Chapter 3 - C# Language Fundamentals

ChapterThe ISite4 interface- Object-definesOrie tedaProgrammingnumber of methodswith C# that allow a Control to interact with the hosting container:

Chapter 5 - Exceptions and Object Lifetime

Chapterpublic6 interface- Inte aces andISiteCollections: IServiceProvider

Chapter{ 7 - Callback Interfaces, Delegates, and Events

Chapter//8 Properties- Advanced C#ofTypetheConstrucISiteioninterfaceTechniques .

Part Threepublic- ProgrammingIComponentwith .NETComponentAssemblies{ get; }

public IContainer Container { get; }

Chapter 9 - Understanding .NET Assemblies

public bool DesignMode { get; }

Chapter 10 - Processes, AppDomains, Contexts, and Threads

public string Name { get; set; }

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)

By and large, the properties defined by the ISite interface are only of interest to you if you are attempting to

Chapter 14 - A Better Painting Framework (GDI+)

build a widget that can be manipulated at design time (such as a custom Windows Forms control).

Chapter 15 - Programming with Windows Forms Controls

ChapterIn addition16 -toThetheSystSitemproperty,.IO NamespaceComponent also provides an implementation of the Dispose() method (as Chapterseen earlier17 - Datain thisAccesschapter)with. RecallADO.NETthat the Dispose() method is called when a component is no longer PartrequiredFive -. Wheneb Applicationsa Form hasandbeenXMLclosed,Web Servicesthe Dispose() method is called automatically for the Form and

for all widgets contained within that form.

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 ControlC#Classand the .NET Platform, Second Edition

The next base class of interest is System.Windows.Forms.Control, which establishes the common behaviors

Apress © 2003 (1200 pages)

required by any GUI-centric type. The core members of System.Windows.Forms.Control allow you to configure

This comprehensive text starts with a brief overview of the

the size and positionC# languageof a control,and extractthen quicklythe underlyingmoves to keyHWNDtechnical(i.e., andnumerical handle for a given window), as well as capture keyboardarchitecturalandissuesmouseforinput.NET. Tabledevelopers13-5.defines some of the properties to be aware of.

Table 13-5: Core Properties of the Control Type

ChapterCreated,4 -Disposed,Object-OrieEntedabled,ProgrammingThesewithpropertiesC# each return a Boolean that specifies the state of

ChapterFocused,5 -VisibleExceptions and Object Lifetimethe current Control.

type. A partial list of some of the more common members appears in Table 13-6.

Index

List of Figures

Table 13-6: Select Members of the Control Type

List of Tables

Control MethodC# and theMeaning.NET Platform,in LifeSecond Edition

These methods are used to manipulate the style flags of the current Control

Apress © 2003 (1200 pages)

using the ControlStyles enumeration.

This comprehensive text starts with a brief overview of the

C# language and then quickly moves to key technical and

These methods indirectly set the state of the Visible property. architectural issues for .NET developers.

Forces the Control to redraw itself by forcing a paint message into the

message queue.

C# and the .NET Platform, Second Edition

and the dozens of oddball styles that can be used to fill the various fields. While Windows Forms hides this

PartWindowsFive - Web"goo"Applicatfrom view,ons youand areXMLableW btoServicesmodify the default styles of your Form if need be. To illustrate, check

Chapout theer 18related- ASPControlStyles.NET Web Pagenumeration:s and Web Controls

Chapter 19 - ASP.NET Web Applications

Chapter 20 - XML Web Services

public enum ControlStyles

Index

{

List of FiguresAllPaintingInWmPaint, CacheText,

List of TablesDoubleBuffer, ContainerControl,

EnableNotifyMessage, FixedHeight,

FixedWidth, Opaque,

ResizeRedraw, Selectable,

StandardClick, StandardDoubleClick,

SupportsTransparentBackColor,

UserMouse, UserPaint

}

The values of the ControlStyle enumeration may OR-ed together if you wish to specify multiple styles. And, as you would expect, a Form has a default style set (I assume you will check out online Help for full details of each value).

Assume you have a Form containing a single Button type. In the Click event handler of this Button, you can check if the Form supports a given style using GetStyle():

Second Edition

ISBN:1590590554

starts with a brief overview of the

quickly moves to key technical and

NET developers.

Table Figureof Contents13-9: ControlStyles.ResizeRedraw = false

C# and the .NET Platform, Second Edition

If you set it to "true" you have correct rendering (Figure 13-10).

Introduction

Part One - Introducing C# and the .NET Platform

Chapter

Chapter

Part

Chapter 8 - Advanced C# Type Construction Techniques

Figure 13-10: ControlStyles.ResizeRedraw = true

Part Three - Programming with .NET Assemblies

Chapter 9 - Understanding .NET Assemblies

ChapterSOURCE10 - Processes,TheAppDoFormStylesains, Contexts,project isandunderTh eadsthe Chapter 13 subdirectory.

CODE

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