实际是用一个Form遮盖另一个。

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  . 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 

     本文转自xyz_lmn51CTO博客，原文链接：http://blog.51cto.com/xyzlmn/819924，如需转载请自行联系原作者