引发自定义控件LoadPostData方法的必要条件!

自定义控件要引发LoadPostData方法，需要包含一个ID为this.UniqueID的控件
可在控件组中加入一个Hidden控件!
writer.Write("")
或者干脆更简单的做法，把submit的name属性设置为me.UniqueID
Imports System.ComponentModel
Imports System.Web.UI
Imports System.Web.UI.WebControls
")> Public Class Login
Inherits System.Web.UI.WebControls.WebControl
Implements IPostBackDataHandler
Public Event CheckError As EventHandler
Private _user As String
Private _pass As String
Public Function LoadPostData(ByVal postDataKey As String, ByVal postCollection As System.Collections.Specialized.NameValueCollection) As Boolean Implements System.Web.UI.IPostBackDataHandler.LoadPostData
_user = CType(postCollection(Me.UniqueID & ":User"), String)
_pass = CType(postCollection(Me.UniqueID & ":Pass"), String)
If _user <> _pass Then
Return True
Else
Return False
End If
End Function
Public Sub RaisePostDataChangedEvent() Implements System.Web.UI.IPostBackDataHandler.RaisePostDataChangedEvent
OnCheckError()
End Sub
Public Sub OnCheckError()
RaiseEvent CheckError(Me, New System.EventArgs())
End Sub
Protected Overrides Sub Render(ByVal writer As System.Web.UI.HtmlTextWriter)
writer.RenderBeginTag(HtmlTextWriterTag.Table)
writer.RenderBeginTag(HtmlTextWriterTag.Tr)
writer.RenderBeginTag(HtmlTextWriterTag.Td)
writer.Write("用户名：")
writer.RenderEndTag()
writer.RenderBeginTag(HtmlTextWriterTag.Td)
writer.AddAttribute(HtmlTextWriterAttribute.Type, "TextBox")