只能输入数字的TextBox

只能接受数字
 1using System;
 2using System.Text;
 3using System.Web;
 4using System.Web.UI;
 5using System.Web.UI.WebControls;
 6
 7
 8namespace PowerAsp.NET.Comtrols
 9{
10    /**//// <summary>
11    /// 作者：黄忠诚
12    /// </summary>
13    public class NumberEditor:TextBox
14    {
15        private const string scp_number_only_hook_id = "9A5788C6-D6A2-484A-9471-3E983A2433F7";
16        private const string scp_number_only_hook = "return NumberEditor_KeyPress_Handle(this);";
17        private const string scp_number_only_script ="<script> function NumberEditor_KeyPress_Handle(ctrl){ if( event.keyCode == 13 ){return true;} if( event.keyCode < 48 || event.keyCode > 57) return false; else return true; }</script>"; 
18            
19
20        private void RenderJavaScript()
21        {
22            if(!Page.IsClientScriptBlockRegistered(scp_number_only_hook_id))
23            {
24                Page.RegisterClientScriptBlock(scp_number_only_hook_id,scp_number_only_script);
25            }
26        }
27        protected override void AddAttributesToRender(HtmlTextWriter writer)
28        {
29            base.AddAttributesToRender (writer);
30            writer.AddAttribute("OnKeyPress",scp_number_only_hook);
31        }
32
33        protected override void OnPreRender(EventArgs e)
34        {
35            base.OnPreRender (e);
36            RenderJavaScript();
37        }
38
39        public NumberEditor()
40        {
41        }
42    }
43}