Action

1

In the SlideShowForm.cs code

using Manning.MyPhotoAlbum;

window, Indicate that we will use

the MyPhotoAlbum library in this file.

2

Create two private fields in the class

private PhotoAlbum _album;

to hold the album and the current

private int _albumPos;

display position.

3

Modify the constructor to accept a

public SlideShowForm(PhotoAlbum album)

PhotoAlbum object and initialize

{

these private fields.

// Required for Form Designer support

InitializeComponent();

// Other initialization

_album = album;

_albumPos = 0;

}

4

Implement a SetInterval method

protected void SetInterval()

to calculate the timer interval based

{

on the value in the text box control.

int interval = 0;

try

Note: Since we do not prevent our

{

text box from containing letters, we

interval

= Convert.ToInt32(txtInterval.Text);

need to catch the possible excep-

}

tion here.

catch

{

// Reset interval value

txtInterval.Text = "2";

interval = 2;

}

slideTimer.Interval = interval * 1000;

}

5

Override the OnLoad method to:

protected override void OnLoad(EventArgs e)

a. Set the timer interval.

{

SetInterval();

b. Enable the timer.

slideTimer.Enabled = true;

c. Set the minimum and maximum

trackSlide.Minimum = 0;

value for the track bar based on

trackSlide.Maximum = _album.Count - 1;

the number of photos in the

base.OnLoad(e);

album.

}

Action

6

Add a Paint event handler for the

private void pboxSlide_Paint

PictureBox control to do the

(object sender,

following:

System.Windows.Forms.PaintEventArgs e)

{

a. If the current position is out of

if (_albumPos >= _album.Count)

range, simply return.

return;

b. Load the current Photograph.

Photograph photo = _album[_albumPos];

c. Display the caption in the title bar.

if (photo != null)

{

d. Preserve the aspect ratio when

this.Text

drawing the image into the

= String.Format("{0} ({1:#}/{2:#})",

window.

photo.Caption,

_albumPos + 1, _album.Count);

e.Graphics.DrawImage(photo.Image,

photo.ScaleToFit(

pboxSlide.ClientRectangle));

}

else

e.Graphics.Clear(SystemColors.Control);

}

7

Add a Tick event handler for the

private void slideTimer_Tick

slideTimer component.

(object sender, System.EventArgs e)

How-to

{

This is the default event for this

component, so simply double-click

the timer in the component tray.

8

In this handler, increment the current

_albumPos ++;

album position.

9

If the position is passed the end of

if (_albumPos > _album.Count)

the album, reset the slide show as

{

follows:

btnStop.Text = "&Start";

_albumPos = 0;

a. Modify the Stop button text to be

trackSlide.Value = 0;

Start.

pboxSlide.Invalidate();

slideTimer.Enabled = false;

b. Reset the track bar value to zero.

}

c. Invalidate the picture box to draw

the initial photograph.

d. Disable the timer.

10

If the position is at the end of the

else if (_albumPos == _album.Count)

album, set the title bar to indicate

{

the slide show is finished.

this.Text = "Finished";

}

11

Otherwise, for a valid album index:

else

a. Invalidate the picture box to draw

{

pboxSlide.Invalidate();

the next image.

trackSlide.Value = _albumPos;

b. Set the track bar value to the cur-

}

rent position.

12

Reassign the interval value to pick up

// Reset the interval

any changes made by the user.

SetInterval();

}

Action

13

Add a Click event handler for the

private void btnClose_Click

Close button to close the form.

(object sender, System.EventArgs e)

{

this.Close();

}

14

Add a Click event handler for the

private void btnStop_Click

Stop button.

(object sender, System.EventArgs e)

{

15

If the current Text value is Stop,

if (btnStop.Text == "&Stop")

stop the timer and set the button

{

text to Resume.

// Stop

slideTimer.Stop();

Note: While our Stop button has

btnStop.Text = "Re&sume";

three different display strings, we

}

preserve the keyboard access key

of Alt+S in all three values.

16

For other text values, start the timer

else

and set the button text to Stop.

{

// Resume or Start

slideTimer.Start();

btnStop.Text = "&Stop";

}

}

17

Add a Scroll event handler for the

private void trackSlide_Scroll

TrackBar control.

(object sender, System.EventArgs e)

Note: This is the default event for

{

the track bar control, and occurs

when the user manually adjusts the

slider position.

18

In this handler:

_albumPos = trackSlide.Value;

a. Set the album position to the new

pboxSlide.Invalidate();

}

value.

b. Invalidate the picture box to draw

the selected photo.

19

Add a Resize event handler for the

private void pboxSlide_Resize

PictureBox control to invalidate the

(object sender, System.EventArgs e)

control and redraw the image.

{

pboxSlide.Invalidate();

}

20

Back in the MainForm class, add a

private void menuSlideShow_Click

Click event handler for the Slide

(object sender, System.EventArgs e)

Show menu to create and display a

{

using (SlideShowForm f

SlideShowForm dialog.

= new SlideShowForm(_album))

{

// Display slide show as modal dialog

f.ShowDialog();

}

}