RICHTEXTBOX 字体背景颜色有关问题(有代码,可看不懂)

RICHTEXTBOX 字体背景颜色问题(有代码,可看不懂)
如题,链接在下,有人能做个小软件上来给大家参考参考么?我看不懂哦~

http://www.cnblogs.com/jerryzhou/archive/2005/06/08/170353.html
有朋友问我怎么在RichTextBox中实现高亮度显示几段文字,其实就是设置几段文字的背景。在.net framework1.1中,RichTextBox不支持SelectionBackColor,从.net framework2.0的帮助文档中,我发现有这个属性,但是没试过。于是,我就顺手写了一个,效果如下:

其实,从Rich Edit Control 2.0 开始就支持设置背景颜色,只不过.net framework没有把它暴露出来而已,我们只需要把它暴露出来。

Rich Edit Control中字符的格式都是通过向控件发送EM_SETCHARFORMAT消息实现的,发送时需要传递两个参数,wParam为格式应用的对象,系统定义了SCF_ALL, SCF_SELECTION等常量,lParam为一个指向类型为CHARFORMAT的指针。详细信息,可以查看MSDN。

下面我们一步一步来实现它:

首先,建一个新的类RichTextBoxEx,继承RichTextBox。需要定义一些常量,你可以在RichEdit.h里面找到这些常量的原始定义:
private const int WM_USER = 0x400;
private const int EM_GETCHARFORMAT = WM_USER + 58;
private const int EM_SETCHARFORMAT = WM_USER + 68;

private const int CFM_BACKCOLOR = 0x04000000;
private const int SCF_SELECTION = 0x0001;

然后,定义CHARFORMAT的数据结构,在Rich Eidt Control 2.0中,使用的是CHARFORMAT2,以前的版本CHARFORMAT不含有背景颜色的定义,所有我们需要使用CHARFORMAT2,这个数据结构的也是在RichEdit.h中声明的:
[StructLayout(LayoutKind.Sequential, Pack=4)]
public class CHARFORMATA2 {
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.ByValArray, SizeConst=0x20)]
public byte[] szFaceName;

public short wWeight;
public short sSpacing;
public int crBackColor;
public int lcid;
public int dwReserved;
public short sStyle;
public short wKerning;
public byte bUnderlineType;
public byte bAnimation;
public byte bRevAuthor;
public byte bReserved1;

public CHARFORMATA2() {
this.cbSize = Marshal.SizeOf(typeof(CHARFORMATA2));
this.szFaceName = new byte[0x20];
}
}
为了向控件发送消息,还需要声明SendMessage方法:
[DllImport("user32.dll", CharSet=CharSet.Auto)]
public static extern IntPtr SendMessage(HandleRef hWnd, int msg, int wParam, [In, Out, MarshalAs(UnmanagedType.LPStruct)] CHARFORMATA2 lParam);

所有准备工作都完成了,下面就可以实现SelectionBackColor了。声明 SelectionBackColor属性,
[Browsable(false)]
public Color SelectionBackColor {
}

Gets方法就是通过发送EM_GETCHARFORMAT消息,读取字符的格式信息,也可以把这部分封装到一个单独的方法里面去:
private CHARFORMATA2 GetSelectionCharFormat() {
CHARFORMATA2 charformata2 = new CHARFORMATA2();
SendMessage(new HandleRef(this, base.Handle), EM_GETCHARFORMAT, SCF_SELECTION, charformata2);
return charformata2;
}
读取里面的背景颜色值返回出来:
get {
Color backColor = Color.Empty;
this.ForceHandleCreate();
CHARFORMATA2 charformat = GetSelectionCharFormat();
if ((charformat.dwMask & CFM_BACKCOLOR) != 0) {
backColor = ColorTranslator.FromOle(charformat.crBackColor);
}
return backColor;
}

Sets方法就是通过发送EM_SETCHARFORMAT,设置字符的格式信息,我们只需要设置背景,可以设置掩码为CFM_BACKCOLOR:
set {
this.ForceHandleCreate();
CHARFORMATA2 charformat= GetSelectionCharFormat();
charformat.dwMask = CFM_BACKCOLOR;
charformat.dwEffects = 0;
charformat.crBackColor = ColorTranslator.ToWin32(value);
SendMessage(new HandleRef(this, base.Handle), EM_SETCHARFORMAT, SCF_SELECTION, charformat);
} 其中,ForceHandleCreate为: