EM_SETCHARFORMAT problem

[c guy3811]

I am trying to set the back color of indavidual charachters in a RichTextBox by using SendMessage() and the charformat2 structure. This works setting the forecolor of the charachters, but the back color will not work. I know that my version of RichEdit supports backcolors because they will show up if I paste, just not with the code. I thought that maybe it was assigning the wrong size to cbSize, but I dont know why it would do that. I am missing something very simple here im sure. I have tried this with the API call and have the same result. The message returns a non zero value, meaning it was successful, but the RichTextBox doesnt reflect that. ... private const int CFM_BACKCOLOR=0x4000000; ..... CHARFORMAT2 cf2=new CHARFORMAT2(); cf2.dwMask=CFM_BACKCOLOR; cf2.cbSize=Marshal.SizeOf(cf2); cf2.crBackColor=ColorTranslator.ToWin32(Color.Red); IntPtr lParam=Marshal.AllocCoTaskMem(Marshal.SizeOf(cf2)); Marshal.StructureToPtr(cf2, lParam, false); Message msg=Message.Create(this.Handle, EM_SETCHARFORMAT, (IntPtr)SCF_SELECTION, lParam); DefWndProc(ref msg); Marshal.FreeCoTaskMem(lParam); Thanks!

[mav northwind]

You'll also have to clear the CFE_AUTOBACKCOLOR flag or your background color will be ignored. Regards, mav

[c guy3811]

Do you mean to set dwEffects=0? I tried that before I posted and nothing. If that isnt what you meant could you elaborate? Thanks!

[mav northwind]

You have to set dwMask to CFM_BACKCOLOR|CFM_COLOR and be sure NOT to set CFE_AUTOBACKCOLOR in dwEffects. Here's the description of the flags you can use: CHARFORMAT2 struct on MSDN[^] Regards, mav

[c guy3811]

I tried all of that before I posted, and tried it again after you posted, and still, nothing. I tried dwEffects=0, dwEffects=CFE_PROTECTED, not setting dwEffects, etc. Nothing has worked. Like I said, the call to DefWndProc is returning a non zero value, so it is working, just not how I want it to. There has to be something I am missing somewhere... I am going to list all my constants, structure, etc, and perhaps someone can figure out what is going on. FYI, I have also tried the API call and it does the same thing. [StructLayout(LayoutKind.Sequential)] private struct CHARFORMAT2 { public int cbSize; public int dwMask; public int dwEffects; public int yHeight; public int yOffset; public int crTextColor; public byte bCharSet; public byte bPitchAndFamily; [MarshalAs(UnmanagedType.ByValTStr, SizeConst=32)] public string szFaceName; public int wWeight; public int sSpacing; public int crBackColor; public int lcid; public int dwReserved; public int sStyle; public int wKerning; public byte bUnderlineType; public byte bAnimation; public byte bRevAuthor; public byte bReserved1; }//struct charformat2 //constants EM_SETCHARFORMAT=0x444; CFM_BACKCOLOR=0x4000000; CFM_COLOR=0x40000000; SCF_SELECTION=0x1; //Call to format, tried CFM_BACKCOLOR and CFM_BACKCOLOR|CFM_COLOR, etc, // only forecolor changes CHARFORMAT2 cf2=new CHARFORMAT2(); cf2.dwMask=CFM_BACKCOLOR; cf2.cbSize=Marshal.SizeOf(cf2); cf2.crBackColor=ColorTranslator.ToWin32(Color.Red); IntPtr lParam=Marshal.AllocCoTaskMem(Marshal.SizeOf(cf2)); Marshal.StructureToPtr(cf2, lParam, false); Message msg=Message.Create(this.Handle, EM_SETCHARFORMAT, (IntPtr)SCF_SELECTION, lParam); DefWndProc(ref msg); Marshal.FreeCoTaskMem(lParam);