这是我过去使用过的RichTextBox。它是从Stack Overflow和整个互联网上的代码拼接而成的：
public class RichBox : RichTextBox { private const UInt32 CFM_BOLD = 0x00000001; private const UInt32 CFM_ITALIC = 0x00000002; private const UInt32 CFM_UNDERLINE = 0x00000004; private const UInt32 CFM_STRIKE = 0x00000008; private const UInt32 CFM_FACE = 0x20000000; private const UInt32 CFM_SIZE = 0x80000000; private const int WM_PAINT = 0xF; private const int WM_SETREDRAW = 0xB; private const int WM_USER = 0x400; private const int EM_SETCHARFORMAT = (WM_USER + 68); private const int SCF_SELECTION = 0x0001; private const int EM_GETEVENTMASK = WM_USER + 59; private const int EM_SETEVENTMASK = WM_USER + 69; private const int EM_GETSCROLLPOS = WM_USER + 221; private const int EM_SETSCROLLPOS = WM_USER + 222; [StructLayout(LayoutKind.Sequential)] private struct CHARFORMAT { public int cbSize; public uint dwMask; public uint dwEffects; public int yHeight; public int yOffset; public int crTextColor; public byte bCharSet; public byte bPitchAndFamily; [MarshalAs(UnmanagedType.ByValArray, SizeConst = 32)] public char[] szFaceName; public short wWeight; public short sSpacing; public int crBackColor; public int LCID; public uint dwReserved; public short sStyle; public short wKerning; public byte bUnderlineType; public byte bAnimation; public byte bRevAuthor; } [Dllimport("kernel32.dll", CharSet = CharSet.Auto)] private static extern IntPtr LoadLibrary(string lpFileName); [Dllimport("user32", CharSet = CharSet.Auto)] private static extern int SendMessage(IntPtr hWnd, int msg, int wParam, ref CHARFORMAT lParam); [Dllimport("user32.dll")] private static extern IntPtr SendMessage(IntPtr hWnd, Int32 wMsg, Int32 wParam, ref Point lParam); [Dllimport("user32.dll")] private static extern IntPtr SendMessage(IntPtr hWnd, Int32 wMsg, Int32 wParam, IntPtr lParam); private bool frozen = false; private Point lastScroll = Point.Empty; private IntPtr lastEvent = IntPtr.Zero; private int lastIndex = 0; private int lastWidth = 0; protected override CreateParams CreateParams { get { var cp = base.CreateParams; if (LoadLibrary("msftedit.dll") != IntPtr.Zero) { cp.ClassName = "RICHEDIT50W"; } return cp; } } [Browsable(false)] [DefaultValue(typeof(bool), "False")] [DesignerSerializationVisibility(DesignerSerializationVisibility.Hidden)] public bool FreezeDrawing { get { return frozen; } set { if (value != frozen) { frozen = value; if (frozen) { this.SuspendLayout(); SendMessage(this.Handle, WM_SETREDRAW, 0, IntPtr.Zero); SendMessage(this.Handle, EM_GETSCROLLPOS, 0, ref lastScroll); lastEvent = SendMessage(this.Handle, EM_GETEVENTMASK, 0, IntPtr.Zero); lastIndex = this.SelectionStart; lastWidth = this.SelectionLength; } else { this.Select(lastIndex, lastWidth); SendMessage(this.Handle, EM_SETEVENTMASK, 0, lastEvent); SendMessage(this.Handle, EM_SETSCROLLPOS, 0, ref lastScroll); SendMessage(this.Handle, WM_SETREDRAW, 1, IntPtr.Zero); this.Invalidate(); this.ResumeLayout(); } } } } [Browsable(false)] [DesignerSerializationVisibility(DesignerSerializationVisibility.Hidden)] public Font CurrentFont { get { Font result = this.Font; if (this.SelectionLength == 0) { result = SelectionFont; } else { using (RichBox rb = new RichBox()) { rb.FreezeDrawing = true; rb.SelectAll(); rb.SelectedRtf = this.SelectedRtf; rb.Select(0, 1); result = rb.SelectionFont; } } return result; } } [Browsable(false)] [DesignerSerializationVisibility(DesignerSerializationVisibility.Hidden)] public string SelectionFontName { get { return CurrentFont.FontFamily.Name; } set { CHARFORMAT cf = new CHARFORMAT(); cf.cbSize = Marshal.SizeOf(cf); cf.szFaceName = new char[32]; cf.dwMask = CFM_FACE; value.CopyTo(0, cf.szFaceName, 0, Math.Min(31, value.Length)); IntPtr lParam = Marshal.AllocCoTaskMem(Marshal.SizeOf(cf)); Marshal.StructureToPtr(cf, lParam, false); SendMessage(this.Handle, EM_SETCHARFORMAT, SCF_SELECTION, lParam); } } [Browsable(false)] [DesignerSerializationVisibility(DesignerSerializationVisibility.Hidden)] public float SelectionFontSize { get { return CurrentFont.Size; } set { CHARFORMAT cf = new CHARFORMAT(); cf.cbSize = Marshal.SizeOf(cf); cf.dwMask = CFM_SIZE; cf.yHeight = Convert.ToInt32(value * 20); IntPtr lParam = Marshal.AllocCoTaskMem(Marshal.SizeOf(cf)); Marshal.StructureToPtr(cf, lParam, false); SendMessage(this.Handle, EM_SETCHARFORMAT, SCF_SELECTION, lParam); } } [Browsable(false)] [DesignerSerializationVisibility(DesignerSerializationVisibility.Hidden)] public bool SelectionBold { get { return CurrentFont.Bold; } set { CHARFORMAT cf = new CHARFORMAT(); cf.cbSize = Marshal.SizeOf(cf); cf.dwMask = CFM_BOLD; cf.dwEffects = value ? CFM_BOLD : 0; IntPtr lParam = Marshal.AllocCoTaskMem(Marshal.SizeOf(cf)); Marshal.StructureToPtr(cf, lParam, false); SendMessage(this.Handle, EM_SETCHARFORMAT, SCF_SELECTION, lParam); } } [Browsable(false)] [DesignerSerializationVisibility(DesignerSerializationVisibility.Hidden)] public bool SelectionItalic { get { return CurrentFont.Italic; } set { CHARFORMAT cf = new CHARFORMAT(); cf.cbSize = Marshal.SizeOf(cf); cf.dwMask = CFM_ITALIC; cf.dwEffects = value ? CFM_ITALIC : 0; IntPtr lParam = Marshal.AllocCoTaskMem(Marshal.SizeOf(cf)); Marshal.StructureToPtr(cf, lParam, false); SendMessage(this.Handle, EM_SETCHARFORMAT, SCF_SELECTION, lParam); } } [Browsable(false)] [DesignerSerializationVisibility(DesignerSerializationVisibility.Hidden)] public bool SelectionStrikeout { get { return CurrentFont.Strikeout; } set { CHARFORMAT cf = new CHARFORMAT(); cf.cbSize = Marshal.SizeOf(cf); cf.dwMask = CFM_STRIKE; cf.dwEffects = value ? CFM_STRIKE : 0; IntPtr lParam = Marshal.AllocCoTaskMem(Marshal.SizeOf(cf)); Marshal.StructureToPtr(cf, lParam, false); SendMessage(this.Handle, EM_SETCHARFORMAT, SCF_SELECTION, lParam); } } [Browsable(false)] [DesignerSerializationVisibility(DesignerSerializationVisibility.Hidden)] public bool SelectionUnderline { get { return CurrentFont.Underline; } set { CHARFORMAT cf = new CHARFORMAT(); cf.cbSize = Marshal.SizeOf(cf); cf.dwMask = CFM_UNDERLINE; cf.dwEffects = value ? CFM_UNDERLINE : 0; IntPtr lParam = Marshal.AllocCoTaskMem(Marshal.SizeOf(cf)); Marshal.StructureToPtr(cf, lParam, false); SendMessage(this.Handle, EM_SETCHARFORMAT, SCF_SELECTION, lParam); } }}它添加了新的属性，例如SelectionBold，SelectionItalic等，您可以在其中应用属性而不会丢失其他格式的文本。
