I've received a question from the customer the other day asking me how he can implement functionality of "dimming" background effect when a message box is shown in his Windows Mobile application. In fact it should be pretty easy to do utilizing the DrawAlpha method from the GraphicsExtender class that I showed you in this webcast. Take a look at the following code snippet:

protected override void OnPaint(PaintEventArgs e)

{

      // Create a temp bitmap

      Bitmap dimBackGround = new Bitmap(this.Width, this.Height);

      Graphics gxTemp = Graphics.FromImage(dimBackGround);

      // Color it black

      gxTemp.Clear(Color.Black);

      // Draw it with alpha transparency

      e.Graphics.DrawAlpha(dimBackGround, 100, 0, 0);

      // Clean up

      gxTemp.Dispose();

      dimBackGround.Dispose();               

 }  

The code above shows OnPaint override method in the BackgroundForm class that I've added to the demo project. I've set the FormBorderStyle to None and WindowState to Maximized for this from to make it full screen.

So, now before displaying a message box you will need to show the BackroundForm:

  BackgroundForm form = new BackgroundForm();

  form.Show();

  MessageBox.Show(txtMessage.Text);

  form.Close();

And here's the result:

Download the sample code from here.