c#中richtextbox设置行距的问题

Question

请问在richtextbox中如何设置行距，我想在记事本中文本框的左边添加行号，用的是一个Label控件，但是由于label控件的行距和richtextbox的行距不一致，越往下行号越来越对不齐了，错开了。
因此我想把label和richtextbox的行距设置成一样。这样就能对齐了。
请问怎样设置。谢谢！！

Answer 1

using System.Runtime.InteropServices;
里面粘贴这些代码
public const int WM_USER = 0x0400;
public const int EM_GETPARAFORMAT = WM_USER + 61;
public const int EM_SETPARAFORMAT = WM_USER + 71;
public const long MAX_TAB_STOPS = 32;
public const uint PFM_LINESPACING = 0x00000100;
[StructLayout(LayoutKind.Sequential)]
private struct PARAFORMAT2
{
public int cbSize;
public uint dwMask;
public short wNumbering;
public short wReserved;
public int dxStartIndent;
public int dxRightIndent;
public int dxOffset;
public short wAlignment;
public short cTabCount;
[MarshalAs(UnmanagedType.ByValArray, SizeConst = 32)]
public int[] rgxTabs;
public int dySpaceBefore;
public int dySpaceAfter;
public int dyLineSpacing;
public short sStyle;
public byte bLineSpacingRule;
public byte bOutlineLevel;
public short wShadingWeight;
public short wShadingStyle;
public short wNumberingStart;
public short wNumberingStyle;
public short wNumberingTab;
public short wBorderSpace;
public short wBorderWidth;
public short wBorders;
}
[DllImport("user32", CharSet = CharSet.Auto)]
private static extern IntPtr SendMessage(HandleRef hWnd, int msg, int wParam, ref PARAFORMAT2 lParam);

private void button1_Click(object sender, EventArgs e)
{
PARAFORMAT2 fmt = new PARAFORMAT2();
fmt.cbSize = Marshal.SizeOf(fmt);
fmt.bLineSpacingRule = 4;
fmt.dyLineSpacing = 40 * (9 + 3);//((int)richTextBox1.Font.Size) * 20 * ((int)ud.Value);
fmt.dwMask = PFM_LINESPACING;
SendMessage(new HandleRef(this.richTextBox1, richTextBox1.Handle), EM_SETPARAFORMAT, 0, ref fmt);
//Console.WriteLine((20 * (9 + 3)) / 15.0);
//16, 17, 19, 20, 23, 25, 26
}

Answer 2

建议设置label的location属性，设置其y属性为richtextbox某行的类似top的属性