让UserControl 成为Asp.Net ajax 控件

很多时候,我们需要用到User Control,将部份UI或业务逻辑包装,下面将UserControl包装成Asp.Net ajax 控件:
简单示例:
(ASCX) 这一段代码就不解释了:

 1
 2 <table>
 3     <tr>
 4         <td>
 5             Login Name:
 6         td>
 7         <td>
 8             <asp:TextBox ID="UserName" Ruant="Server">asp:TextBox>
 9         td>
10     tr>
11     <tr>
12         <td>
13             Password:
14         td>
15         <td>
16             <asp:TextBox ID="Password" TextMode="Password" Ruant="Server">asp:TextBox>
17         td>
18     tr>
19 table>

(LoginPanel.js)

 1 <script type="text/javascript">
 2     ///
 3     Type.registerNamespace("CsharpFarmer");
 4     CsharpFarmer.LoginPanel= function(element) {
 5         CsharpFarmer.LoginPanel.initializeBase(this, [element]);
 6         this.userName = null;
 7         this.password = null;
 8     }
 9     CsharpFarmer.LoginPanel.prototype = {
10         initialize: function() {
11             CsharpFarmer.LoginPanel.callBaseMethod(this, 'initialize');
12             // Add custom initialization here
13         },
14         get_userName: function() {
15             return this.userName ;
16         },
17         set_userName: function(value) {
18             this.userName = value;
19         },
20         get_password: function() {
21             return this.password ;
22         },
23         set_password: function(value) {
24             this.password = value;
25         },
26         dispose: function() {
27             //Add custom dispose actions here
28             CsharpFarmer.LoginPanel.callBaseMethod(this, 'dispose');
29             delete this.userName;
30             delete this.password;
31         }
32     }
33     CsharpFarmer.LoginPanel.registerClass(CsharpFarmer.LoginPanel, Sys.UI.Control);
34 </script>

(控件相对应的js,注意get和set方法必须成对出现,与属性以"_"隔开,),至于为什么,只是一种规定,查看MsAjax:
中:Sys$Component$_setProperties:

Code
function Sys$Component$_setProperties(target, properties) {
    ///
    ///
    ///
    var e = Function._validateParams(arguments, [
        {name: "target"},
        {name: "properties"}
    ]);
    if (e) throw e;
    var current;
    var targetType = Object.getType(target);
    var isObject = (targetType === Object) || (targetType === Sys.UI.DomElement);
    var isComponent = Sys.Component.isInstanceOfType(target) && !target.get_isUpdating();
    if (isComponent) target.beginUpdate();
    for (var name in properties) {
        var val = properties[name];
        var getter = isObject ? null : target["get_" + name];
        if (isObject || typeof(getter) !== 'function') {
            var targetVal = target[name];
            if (!isObject && typeof(targetVal) === 'undefined') throw Error.invalidOperation(String.format(Sys.Res.propertyUndefined, name));
            if (!val || (typeof(val) !== 'object') || (isObject && !targetVal)) {
                target[name] = val;
            }
            else {
                Sys$Component$_setProperties(targetVal, val);
            }
        }
        else {
            var setter = target["set_" + name];
            if (typeof(setter) === 'function') {
                setter.apply(target, [val]);
            }
            else if (val instanceof Array) {
                current = getter.apply(target);
                if (!(current instanceof Array)) throw new Error.invalidOperation(String.format(Sys.Res.propertyNotAnArray, name));
                for (var i = 0, j = current.length, l= val.length; i < l; i++, j++) {
                    current[j] = val[i];
                }
            }
            else if ((typeof(val) === 'object') && (Object.getType(val) === Object)) {
                current = getter.apply(target);
                if ((typeof(current) === 'undefined') || (current === null)) throw new Error.invalidOperation(String.format(Sys.Res.propertyNullOrUndefined, name));
                Sys$Component$_setProperties(current, val);
            }
            else {
                throw new Error.invalidOperation(String.format(Sys.Res.propertyNotWritable, name));
            }
        }
    }
    if (isComponent) target.endUpdate();
}

LoginPanel.cs

 1 using System;
 2 using System.Collections.Generic;
 3 using System.Linq;
 4 using System.Web;
 5 using System.Web.UI;
 6 using System.Web.UI.WebControls;
 7 using System.Text;
 8
 9 ///
10 /// LoginPanel
11 ///
12 public partial class LoginPanel : System.Web.UI.UserControl, IScriptControl
13 {
14
15     protected void Page_Load(object sender, EventArgs e)
16     {
17
18     }
19
20     protected override void Render(HtmlTextWriter writer)
21     {
22         writer.AddAttribute(HtmlTextWriterAttribute.Id, this.ClientID);
23         writer.RenderBeginTag("Div");
24         base.Render(writer);
25         writer.RenderEndTag();
26     }
27
28     protected override void OnPreRender(EventArgs e)
29     {
30         base.OnPreRender(e);
31         var sm = ScriptManager.GetCurrent(this.Page);
32         sm.RegisterScriptControl<LoginPanel>(this);
33         sm.RegisterScriptDescriptors(this);
34     }
35
36    
37     #region IScriptControl
38
39     public IEnumerable<ScriptDescriptor> GetScriptDescriptors()
40     {
41         var descriptor = new ScriptControlDescriptor("CsharpFarmer.LoginPanel", this.ClientID);
42         descriptor.AddElementProperty("userName", UserName.ClientID);
43         descriptor.AddElementProperty("password", Password.ClientID);
44         yield return descriptor;
45     }
46
47     public IEnumerable<ScriptReference> GetScriptReferences()
48     {
49         var sr = new ScriptReference("~/LoginPanel.js");
50         yield return sr;
51     }
52
53     #endregion
54 }
55
这一段代码中应当注意,必须