1 using System;
 2 using System.Web.UI;
 3 using System.Web.UI.WebControls;
 4 using System.ComponentModel;
 5 
 6 namespace MyCompany.Controls
 7 {
 8     public class SubmitTextBox : TextBox
 9     {
10         /// <summary>
11         /// 用来指定按回车时由哪个按钮来响应
12         /// </summary>
13         [TypeConverter(typeof(SubmitableControlConvertor)), DefaultValue(""),Category("Behavior")]
14         public string SubmitControl
15         {
16             get
17             {
18                 object ret = this.ViewState["SubmitControl"];
19                 if (ret != null)
20                 {
21                     return (string) ret;
22                 }
23                 return string.Empty; 
24             } 
25             set 
26             {
27                 this.ViewState["SubmitControl"] = value;
28             }
29         }
30 
31         protected override void AddAttributesToRender(HtmlTextWriter writer) 
32         {
33             base.AddAttributesToRender(writer);
34             if(this.SubmitControl.Length > 0)
35             {
36                 Control con = FindControl(SubmitControl);
37                 if(con != null)
38                 {
39                     string script = "if(event.keyCode == 13){document.getElementById('" + con.ClientID + "').click();event.returnValue=false;}";
40                     writer.AddAttribute("onkeydown",script);
41                 }
42             }
43         } 
44     } 
45 }

 1 using System;
 2 using System.Web.UI;
 3 using System.Web.UI.WebControls;
 4 using System.ComponentModel;
 5 using System.Collections;
 6 
 7 namespace MyCompany.Controls
 8 {
 9     public class SubmitableControlConvertor : StringConverter
10     {
11         private object[] GetControls(IContainer container)
12         {
13             ComponentCollection components = container.Components;
14             ArrayList ret = new ArrayList();
15             foreach (IComponent control in components)
16             {
17                 if (!(control is Button || control is LinkButton || control is ImageButton))
18                 {
19                     continue;
20                 }
21                 Control button = (Control) control;
22                 if ((button.ID != null) && (button.ID.Length != 0))
23                 {
24                     ret.Add(string.Copy(button.ID));
25                 }
26             }
27             ret.Sort(Comparer.Default);
28             return ret.ToArray();
29         }
30  
31         public override System.ComponentModel.TypeConverter.StandardValuesCollection GetStandardValues(ITypeDescriptorContext context)
32         {
33             if ((context != null) && (context.Container != null))
34             {
35                 object[] controls = this.GetControls(context.Container);
36                 if (controls != null)
37                 {
38                     return new TypeConverter.StandardValuesCollection(controls);
39                 }
40             }
41             return null;
42         }
43 
44         public override bool GetStandardValuesExclusive(ITypeDescriptorContext context)
45         {
46             return false;
47         }
48 
49         public override bool GetStandardValuesSupported(ITypeDescriptorContext context)
50         {
51             return true;
52         }
53     } 
54 }

1 <%@ Control Language="c#"%>
2 <%@ Register TagPreFix="MyCompany" Namespace="MyCompany.Controls" Assembly="MyCompany.Controls"%>
3 <MyCompany:SUBMITTEXTBOX id="txtKeys" SubmitControl="btnSearch" runat="server" maxlength="20" Value="请输入搜索关键字" onfocus="if(this.value=='请输入搜索关键字')this.value='';" onblur="if(this.value=='')this.value='请输入搜索关键字'"></MyCompany:SUBMITTEXTBOX>&nbsp;&nbsp;&nbsp;<asp:imagebutton id="btnSearch" runat="server"></asp:imagebutton>