更改Richtextbox的字体而不会丢失格式
如何在不丢失格式的情况下更改富文本框所有内容的字体？
我正在尝试使用
rtb.SelectAll();rtb.SelectionFont = new Font(fontName,...);
但是字体构造函数除了字体类型外还必须采用字体样式（粗体，斜体等）或字体大小。因此，使用此选项将更改richtextbox所有内容的样式/大小。
当然，富文本框中的任何选择也是如此。
回答：
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。
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