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Using CreateParams with MDI Child

I am attempting to override CreateParams in an MDI child. The MSDN documentation states that to successfully do this you have to reference ClientCreateStruct. However, I cannot find any code samples for doing this. Can somone share with me the code for overriding CreateParams in an MDI child form?

DavidAnderson Tuesday, December 02, 2008 4:03 PM

That's not going to work. Drop shadows are created by a video overlay. These overlays only work on overlapped windows, not child windows. The TransparencyKey and Opacity properties don't work either, for the same reason.

nobugz Tuesday, December 02, 2008 8:09 PM

DavidAnderson wrote:

I am attempting to override CreateParams in an MDI child. The MSDN documentation states that to successfully do this you have to reference ClientCreateStruct. However, I cannot find any code samples for doing this. Can somone share with me the code for overriding CreateParams in an MDI child form?

Post the link that you are referring to.

Rudedog2 Tuesday, December 02, 2008 4:41 PM

The CLIENTCREATESTRUCT contains the handle of a MDI applications main menu and the id of the first MDI child. Its pointer is used as the lpParam of the CreateWindow and CreateWindowEx functions.
You should not care about it as long as you are using the base classes CreateParams; ie:

CreateParams cp = base.CreateParams;
cp.ExStyle |= 0x20;
return cp;

KomplexoR Tuesday, December 02, 2008 5:09 PM

http://msdn.microsoft.com/en-us/library/ms632602(VS.85).aspx

DavidAnderson Tuesday, December 02, 2008 7:21 PM

This is the code I am using. When attached to the parent, it creates a shadow. When attached to a child, it does not work:

Code Snippet

private const int CS_DROPSHADOW = 0x00020000;

public Preferences()

{

InitializeComponent();

comboRowsPerPage.SelectedIndex = 0;

}

protected override CreateParams CreateParams

{

get

{

CreateParams p = base.CreateParams;

p.ClassStyle = p.ClassStyle | CS_DROPSHADOW;

return p;

}

DavidAnderson Tuesday, December 02, 2008 7:24 PM

nobugz Tuesday, December 02, 2008 8:09 PM

Are there any options?

DavidAnderson Tuesday, December 02, 2008 8:14 PM

David,

Did you find a solution ?, seems like just you and me have this problem.

I have found a component with source code that does it with modal forms, I made it work, but when moving th mdichild to the parent form's border, tha shadow appears outside the parent form:

Dropshadow Component
http://insystusa.com/Products.aspx

Could youprovide me some feedback ?

Thanks in advance.

George Waters Friday, September 18, 2009 10:26 PM

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