ScrollWindowEx and drawing in C#

[Ivonne Riedel]

Working on an incremental drawing algorithm I am facing a problem PInvoking
ScrollWindowEx:
The code is as follows...


C#:
[DllImport("user32.dll")]
public static extern int ScrollWindowEx(IntPtr hWnd, int
dx, int dy, IntPtr scrollRect, IntPtr clipRect, IntPtr
hrgn, ref Rectangle updateRect, uint flags);

Rectangle update = new Rectangle();

ScrollWindowEx(
this.Handle,
this.ClientRectangle.X - hScrollBar.Value,
0,
IntPtr.Zero,
IntPtr.Zero,
IntPtr.Zero,
ref update,
0);

C++:

child->ScrollWindowEx(child->fenster_pos.x-pos,0,NULL,NULL,NULL,&update,0);

There is a difference in the values between calling ScrollWindowEx in C++
and through the PInvoke with C#.
The arguments are identical but not the results (update.left, scrolling only
horizontally).
Can anybody identify the problem or my mistake?
Thanks in advance.

Ivonne.

 

[Willy Denoyette [MVP]]

Check or post your declararation of Rectangle.

Willy.

| Working on an incremental drawing algorithm I am facing a problem
PInvoking
| ScrollWindowEx:
| The code is as follows...
|
|
| C#:
| [DllImport("user32.dll")]
| public static extern int ScrollWindowEx(IntPtr hWnd, int
| dx, int dy, IntPtr scrollRect, IntPtr clipRect, IntPtr
| hrgn, ref Rectangle updateRect, uint flags);
|
| Rectangle update = new Rectangle();
|
| ScrollWindowEx(
| this.Handle,
| this.ClientRectangle.X - hScrollBar.Value,
| 0,
| IntPtr.Zero,
| IntPtr.Zero,
| IntPtr.Zero,
| ref update,
| 0);
|
| C++:
|
|
child->ScrollWindowEx(child->fenster_pos.x-pos,0,NULL,NULL,NULL,&update,0);
|
| There is a difference in the values between calling ScrollWindowEx in C++
| and through the PInvoke with C#.
| The arguments are identical but not the results (update.left, scrolling
only
| horizontally).
| Can anybody identify the problem or my mistake?
| Thanks in advance.
|
| Ivonne.
|
|

 

[Ivonne Riedel]

I used the C# System.Drawing Rectangle.
I did not make any modifications to it.
Do you see this as the mistake?

Thanks

Ivonne.

 

[Willy Denoyette [MVP]]

Yes I do, Rectangle in System.Drawing != Rectangle in User32.
So you need to declare a structure like this:

struct Rect{
public int left;
public int top;
public int right;
public int bottom;
}

Willy.


|I used the C# System.Drawing Rectangle.
| I did not make any modifications to it.
| Do you see this as the mistake?
|
| Thanks
|
| Ivonne.
|
Newsbeitrag
| | > Check or post your declararation of Rectangle.
| >
| > Willy.
| >
| > | > | Working on an incremental drawing algorithm I am facing a problem
| > PInvoking
| > | ScrollWindowEx:
| > | The code is as follows...
| > |
| > |
| > | C#:
| > | [DllImport("user32.dll")]
| > | public static extern int ScrollWindowEx(IntPtr hWnd, int
| > | dx, int dy, IntPtr scrollRect, IntPtr clipRect, IntPtr
| > | hrgn, ref Rectangle updateRect, uint flags);
| > |
| > | Rectangle update = new Rectangle();
| > |
| > | ScrollWindowEx(
| > | this.Handle,
| > | this.ClientRectangle.X - hScrollBar.Value,
| > | 0,
| > | IntPtr.Zero,
| > | IntPtr.Zero,
| > | IntPtr.Zero,
| > | ref update,
| > | 0);
| > |
| > | C++:
| > |
| > |
| >
child->ScrollWindowEx(child->fenster_pos.x-pos,0,NULL,NULL,NULL,&update,0);
| > |
| > | There is a difference in the values between calling ScrollWindowEx in
| > C++
| > | and through the PInvoke with C#.
| > | The arguments are identical but not the results (update.left,
scrolling
| > only
| > | horizontally).
| > | Can anybody identify the problem or my mistake?
| > | Thanks in advance.
| > |
| > | Ivonne.
| > |
| > |
| >
| >
|
|