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RadForm

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george
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george asked on 19 Mar 2009, 12:23 PM
I have been noticing that on your RadForm there is a problem with how you get your GetDCEx. To keep it short I'll give you a short piece of code that can help you.

public

static IntPtr GetDC(Message msg)

 

{

 

 

if (msg.Msg != (int)WindowMessages.WM_NCPAINT)

{

 

return GetWindowDC(msg.HWnd);

}

 

int flags = (int)(DCX.DCX_CACHE | DCX.DCX_CLIPSIBLINGS | DCX.DCX_WINDOW );

 

IntPtr zero = IntPtr.Zero;

 

 

if (msg.WParam.ToInt32() != 1)

{

flags |= (

 

int)DCX.DCX_INTERSECTRGN;

 

 

zero = msg.WParam;

 

 

}

return GetDCEx(msg.HWnd, zero, flags);

}

 


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Nick
Telerik team
answered on 20 Mar 2009, 06:09 PM
Hi george,

Thank you for writing.

I am afraid that I do not understand where the problem is. Can you elaborate a bit on your code? Thank you very much in advance.

Regards,
Nick
the Telerik team

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george
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answered on 23 Mar 2009, 04:31 PM
I download your RadControls for WinForms Q3 2008 SP2. I notice that the RadForm (FirstLook) wasn't actually not drawing the non-client area of the form until I size the form . So I did a little research by examing your library with Red Gate's .NET Reflector and I notice that in your PaintNC(wm_ncpaint) method that you was going about it the wrong way. MSDN states that ....

The DefWindowProc function paints the window frame.

An application can intercept the WM_NCPAINT message and paint its own custom window frame. The clipping region for a window is always rectangular, even if the shape of the frame is altered.

The wParam value can be passed to GetDCEx as in the following example.

case WM_NCPAINT:
{
    HDC hdc;
    hdc = GetDCEx(hwnd, (HRGN)wParam, DCX_WINDOW|DCX_INTERSECTRGN);
    // Paint into this DC
    ReleaseDC(hwnd, hdc);
}

First off ---- The update region is clipped to the window frame. When wParam is 1, the entire window frame
needs to be updated. How you got it is the same as MSDN states it. This is for use when the wParam not
equal 1. If the wParam equals 1 the entire window frame needs to be updated. So you don't need
DCX_INTERSECTRGN when it equals 1. So the piece of code thats on this page was used for in a project of
mines. So I want to share somthing that I had problems with and I see that your team got now. Here is a
piece of code to go about it (example)...All of this is done on a subclass of a System.Windows.Forms.Form.

protected override void WndProc(ref Message m)
        {
switch (m.Msg)
            {
case (int)WindowMessages.WM_NCPAINT: //0x85
                    WmNCPaint(ref m);
                    break;
default:
                    base.WndProc(ref m);
                    break;
            }  
}


















private void WmNCPaint(ref Message msg)
        {

            RECT windowRect = new RECT();
            if (GetWindowRect(msg.HWnd, ref windowRect) == false)
                return;

            Rectangle bounds = new Rectangle(0, 0,
                windowRect.right - windowRect.left,
                windowRect.bottom - windowRect.top);

            if (bounds.Width == 0 || bounds.Height == 0)
                return;

            // retrieves the device context (DC) for the entire window,
            // including title bar, menus, and scroll bars
            IntPtr hDC = GetDC(msg);
            if (hDC == IntPtr.Zero)
                return;

            // assign clip region to exclude client area


            Rectangle clientRect = ExcludePadding(bounds, this.ClientAreaOffSet);
            ExcludeClipRect(hDC, clientRect.Left, clientRect.Top, clientRect.Right, clientRect.Bottom);

           

            try
            {
                // Double-buffering technique the old way
                IntPtr CompatiblehDC = CreateCompatibleDC(hDC);
                IntPtr CompatibleBitmap = CreateCompatibleBitmap(hDC, bounds.Width, bounds.Height);

                try
                {
                    SelectObject(CompatiblehDC, CompatibleBitmap);

                    using (Graphics g = Graphics.FromHdc(CompatiblehDC))
                    {
                        // Do your drawing here.
                    }

                    // copy current bitmap to screen, blast bits to screen
                    BitBlt(hDC, 0, 0, bounds.Width, bounds.Height, CompatiblehDC, 0, 0, 0x00CC0020/*SRCCOPY*/);
                    //goto Label_0178;
                }
                finally
                {
                    DeleteObject(CompatibleBitmap);
                    DeleteDC(CompatiblehDC);
                }
            }
            finally
            {
                //DeleteObject(hrgnClip);
                ReleaseDC(msg.HWnd, hDC);
            }

            //Label_0178:
            // we handled everything MSDN states that an application returns zero if it processes
// this message.


            msg.Result = ((IntPtr)0);
        }

 

public static IntPtr GetDC(Message msg)
        {

            if (msg.Msg != (int)WindowMessages.WM_NCPAINT)
            {
                return GetWindowDC(msg.HWnd);
            }
            int flags = (int)(DCX.DCX_CACHE | DCX.DCX_CLIPSIBLINGS
             | DCX.DCX_WINDOW );

            IntPtr zero = IntPtr.Zero;
            if (msg.WParam.ToInt32() != 1)
            {
                flags |= (int)DCX.DCX_INTERSECTRGN;//0x80;
                zero = msg.WParam;

            }
// check out http://www.codeproject.com/KB/GDI/updatergn.aspx on GetDCEx
// the best I seen so far on this
            return GetDCEx(msg.HWnd, zero, flags);
        }

 Still need to elaborate a lit bit more just post.

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Deyan
Telerik team
answered on 25 Mar 2009, 04:25 PM
Hi George,

Thanks for your response and for the details provided.

I would like to inform you that we are going to investigate the code that you provided and we are also going to update our code according to the requirements if needed.

I have updated your Telerik points for pointing this out to us.

Regards,
Deyan
the Telerik team

Check out Telerik Trainer , the state of the art learning tool for Telerik products.
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