控制只能输入整数或小数(供TextBox注册KeyPress事件)#region 控制只能输入整数或小数(供TextBox注册KeyPress事件)
        /**//// <summary>
        /// 控制只能输入整数或小数
        /// (小数位最多位4位，小数位可以自己修改)
        /// </summary>
        /// <param name="sender"></param>
        /// <param name="e"></param>
        private void Txb_Decimal_KeyPress(object sender, System.Windows.Forms.KeyPressEventArgs e)
        {
            if(!(((e.KeyChar >= '0') && (e.KeyChar <= '9')) || e.KeyChar <= 31))
            {
                if(e.KeyChar == '.')
                {
                    if ( ((TextBox)sender).Text.Trim().IndexOf('.') > -1)
                        e.Handled   = true;
                }
                else
                    e.Handled = true;
            }    
            else
            {
                if( e.KeyChar <= 31 )
                {
                    e.Handled = false ;
                }
                else if( ((TextBox)sender).Text.Trim().IndexOf('.') > -1 )
                {
                    if( ((TextBox)sender).Text.Trim().Substring(((TextBox)sender).Text.Trim().IndexOf('.') + 1 ).Length >= 4)
                        e.Handled = true ;
                }                
            }
        }
        #endregion

------解决方案--------------------
http://www.soft000.com/lt/topic.asp?l_id=6&t_id=68
重写TEXTBOX

------解决方案--------------------
这是我重写的一个TextBox控件，希望对你有用
/**********************************************************************
  * Created by : Sunny.li
  * Create Date: 2007/11/09
  * Description:  
  * Samples	  :
  *  
  **********************************************************************/
using System;
using System.ComponentModel;
using System.Drawing;
using System.Drawing.Drawing2D;
using System.Runtime.InteropServices;
using System.Windows.Forms;

namespace MyApp
{
   public class NumberBox : System.Windows.Forms.TextBox
   {

       public NumberBox()
       {
           this.TextAlign = HorizontalAlignment.Right;
       }

       public enum NumberType
       {
           intNumber,
           DecimalNumber
       }

       private NumberType numberType = NumberType.intNumber;
       /// <summary>
       /// get or set the Number Type
       /// </summary>
       public NumberType Numbertype
       {
           get
           {
               return numberType;
           }
           set
           {
               numberType = value;
           }
       }


       private int iNumberLength = 10;
       /// <summary>
       /// get or set the integral' length of Number 
       /// </summary>
       public int INumberLength
       {
           set
           {
               iNumberLength = value;
           }
           get
           {
               return iNumberLength;
           }
       }

       protected override void OnKeyPress(KeyPressEventArgs e)
       {
           base.OnKeyPress(e);

           if (numberType == NumberType.intNumber)
           {
               if (IsNum(e.KeyChar))
                   e.Handled = false;//允许输出
               else
                   e.Handled = true;//禁止输出
           }
           else
           {
               if (IsDecimal(e.KeyChar))
                   e.Handled = false;//允许输出