C# 如何设置 richTextBoxr的边距

附件 http://files.cnblogs.com/xe2011/richTextBox_EM_SETRECT.rar

using System.Runtime.InteropServices; 

 public struct Rect
        {
            public int Left;
            public int Top;
            public int Right;
            public int Bottom;
        }

        [DllImport("user32.dll")]
        private static extern int SendMessage(IntPtr hwnd, int wMsg, IntPtr wParam, ref Rect lParam);//

        private const int EM_GETRECT = 0x00b2;
        private const int EM_SETRECT = 0x00b3;

        public Rect RichTextBoxMargin
        {
            get
            {
                Rect rect = new Rect();
                SendMessage(richTextBox1.Handle, EM_GETRECT, IntPtr.Zero, ref rect);
                rect.Left += ;
                rect.Top += ;
                rect.Right =  + richTextBox1.ClientSize.Width - rect.Right;
                rect.Bottom = richTextBox1.ClientSize.Height - rect.Bottom;
                return rect;
            }
            set
            {
                Rect rect;
                rect.Left =  richTextBox1.ClientRectangle.Left + value.Left;
                rect.Top =   richTextBox1.ClientRectangle.Top + value.Top;
                rect.Right =  richTextBox1.ClientRectangle.Right - value.Right;
                rect.Bottom =  richTextBox1.ClientRectangle.Bottom - value.Bottom;

                SendMessage(richTextBox1.Handle, EM_SETRECT, IntPtr.Zero, ref rect);
            }

        }

        //设置
        private void button1_Click(object sender, EventArgs e)
        {
            Rect rect;
            rect.Left = ;
            rect.Top = ;
            rect.Right = ;
            rect.Bottom = ;

            RichTextBoxMargin = rect;
        }

        //获得
        private void button2_Click(object sender, EventArgs e)
        {
            Rect rect;
            rect = RichTextBoxMargin;

            MessageBox.Show( string.Format("Left = {0} top={1} right={2} bottom={3}",rect.Left,rect.Top,rect.Right,rect.Bottom));
        }

放在自定义的类里面

 using System;
 using System.Collections.Generic;
 using System.Linq;
 using System.Text;
 using System.Runtime.InteropServices;

 namespace System.Windows.Forms
 {
     public class CustomRichTextBox:RichTextBox
     {
         public CustomRichTextBox()
         {
             richTextBox1=this;
         }
         private System.Windows.Forms.RichTextBox richTextBox1;

         private struct Rect
         {
             public int Left;
             public int Top;
             public int Right;
             public int Bottom;
         }

         [DllImport("user32.dll")]
         private static extern int SendMessage(IntPtr hwnd, int wMsg, IntPtr wParam, ref Rect lParam);

         private const int EM_GETRECT = 0x00b2;
         private const int EM_SETRECT = 0x00b3;

         /// <summary>
         /// 当没设置的时候结果多出了L T R +2
         /// </summary>
         private Rect RichTextBoxMargin
         {
             get
             {
                 Rect rect = new Rect();
                 SendMessage(richTextBox1.Handle, EM_GETRECT, IntPtr.Zero, ref rect);
                 rect.Left += ;
                 rect.Top += ;
                 rect.Right =  + richTextBox1.DisplayRectangle.Width - rect.Right;
                 rect.Bottom = richTextBox1.DisplayRectangle.Height - rect.Bottom;
                 return rect;
             }
             set
             {
                 Rect rect;
                 rect.Left = richTextBox1.ClientRectangle.Left + value.Left;
                 rect.Top = richTextBox1.ClientRectangle.Top + value.Top;
                 rect.Right = richTextBox1.ClientRectangle.Right - value.Right;
                 rect.Bottom = richTextBox1.ClientRectangle.Bottom - value.Bottom;

                 SendMessage(richTextBox1.Handle, EM_SETRECT, IntPtr.Zero, ref rect);
             }

         }

         public int LeftMargin
         {
             get
             {
                 return RichTextBoxMargin.Left;
             }
             set
             {
                 Rect rect1;
                 rect1 = RichTextBoxMargin;

                 Rect rect;
                 rect.Left = value;
                 rect.Top = rect1.Top;
                 rect.Right = rect1.Right;
                 rect.Bottom = rect1.Bottom;

                 RichTextBoxMargin = rect;
             }
         }

         public int RightMargin
         {
             get
             {
                 return RichTextBoxMargin.Right;
             }
             set
             {
                 Rect rect1;
                 rect1 = RichTextBoxMargin;

                 Rect rect;
                 rect.Left = rect1.Left;
                 rect.Top = rect1.Top;
                 rect.Right = value;
                 rect.Bottom = rect1.Bottom;

                 RichTextBoxMargin = rect;
             }
         }

         public int TopMargin
         {
             get
             {
                 return RichTextBoxMargin.Top;
             }
             set
             {
                 Rect rect1;
                 rect1 = RichTextBoxMargin;

                 Rect rect;
                 rect.Left = rect1.Left;
                 rect.Top = value;
                 rect.Right = rect1.Right;
                 rect.Bottom = rect1.Bottom;

                 RichTextBoxMargin = rect;
             }
         }

         public int BottomMargin
         {
             get
             {
                 return RichTextBoxMargin.Bottom;
             }
             set
             {
                 Rect rect1;
                 rect1 = RichTextBoxMargin;

                 Rect rect;
                 rect.Left = rect1.Left;
                 rect.Top = rect1.Top;
                 rect.Right = rect1.Right;
                 rect.Bottom = value;
                 RichTextBoxMargin = rect;
             }
         }

     }
 }

CustomRichTextBox.cs

使用

         private void button1_Click(object sender, EventArgs e)
         {
             customRichTextBox1.LeftMargin = ;
             customRichTextBox1.TopMargin = ;
             customRichTextBox1.RightMargin = ;
             customRichTextBox1.BottomMargin = ;
         }

         private void button2_Click(object sender, EventArgs e)
         {
             Text = string.Format("Left={0} Right={1} Top={2} Bottom={3}",
                 customRichTextBox1.LeftMargin,
                 customRichTextBox1.TopMargin,
                 customRichTextBox1.RightMargin,
                 customRichTextBox1.BottomMargin);
         }