c# winform 中如何限制文本框只能输入数字及小数点（并且只能输入1次）
c# winform 中如何限制文本框只能输入数字及小数点（并且只能输入1次）

谢谢

[解决办法]

C# code

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
[解决办法]
http://www.soft000.com/lt/topic.asp?l_id=6&t_id=68
重写TEXTBOX
[解决办法]
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 
 
               else
                   e.Handled = true;//禁止输出
           }
       }

       private bool IsNum(char keyChar)
       {
           if (((keyChar >= 48 && keyChar <= 57)) || keyChar == 8)
           {
               if (this.Text.Trim().Length <= iNumberLength-1)
                   return true;
               else
                   return false;
           }
           else
               return false;

       }

       private bool IsDecimal(char keyChar)
       {
           if (((keyChar >= 48 && keyChar <= 57)) || keyChar == 8 || keyChar == 46)
           {
               if (this.Text.Trim().LastIndexOf('.') <= iNumberLength)
               {
                   if (this.Text.Trim().Contains(".") && keyChar == 46)
                       return false;
                   else
                       return true;
               }
               else
               {
                   if (keyChar != 8)
                   {
                       return false;
                   }
                   return true;
               }
           }
           else
               return false;

       }
   }
}