动态创建控件

由于页面生命周期的关系，事先创建的空间在点击其他任何按钮后会消失，原因在于未保存状态。解决方法在Page_Load函数IsPostBack中创建与之ID相同的控件，便能保存状态。

页面代码

View Code

   
     

    
      <
    
      div
    
      >
    
      　　

 
    
      <
    
      asp:Button ID
    
      =
    
      "
    
      BtnCreCon
    
      "
    
       runat
    
      =
    
      "
    
      server
    
      "
    
       Text
    
      =
    
      "
    
      Button
    
      "
    
       onclick
    
      =
    
      "
    
      BtnCreCon_Click
    
      "
    
       
    
      />
    
      
 
 
    
      <
    
      asp:Button ID
    
      =
    
      "
    
      BtnShowMess
    
      "
    
       runat
    
      =
    
      "
    
      server
    
      "
    
       Text
    
      =
    
      "
    
      Button
    
      "
    
       onclick
    
      =
    
      "
    
      BtnShowMess_Click
    
      "
    
       
    
      />
    
      
 
 
    
      <
    
      asp:Panel ID
    
      =
    
      "
    
      PCreateCon
    
      "
    
       runat
    
      =
    
      "
    
      server
    
      "
    
      >
    
      
 
    
      </
    
      asp:Panel
    
      >
    
      
 
    
      <
    
      asp:Literal ID
    
      =
    
      "
    
      LtlShowMess
    
      "
    
       runat
    
      =
    
      "
    
      server
    
      "
    
      ></
    
      asp:Literal
    
      >
    
      


    
      </
    
      div
    
      >
   
     

后台代码

  
    

   
     TextBox tbx;
 
   
     private
   
      
   
     int
   
      Id
 {
 
   
     get
   
      { 
 
   
     string
   
      id
   
     =
   
     Convert.ToString( ViewState[
   
     "
   
     Id
   
     "
   
     ]);
 
   
     if
   
      (
   
     string
   
     .IsNullOrEmpty(id))
 
   
     return
   
      
   
     0
   
     ;
 
   
     else
   
     
 
   
     return
   
      Convert.ToInt32(id);
 }
 
   
     set
   
      { ViewState[
   
     "
   
     Id
   
     "
   
     ] 
   
     =
   
      value; }
 }


 
   
     private
   
      
   
     void
   
      CreateTextBoxListForLoad()
 {
 
   
     for
   
      (
   
     int
   
      i 
   
     =
   
      
   
     0
   
     ; i 
   
     <
   
      Id; i
   
     ++
   
     )
 {
 tbx 
   
     =
   
      
   
     new
   
      TextBox();

 tbx.ID 
   
     =
   
      
   
     "
   
     Tbx
   
     "
   
      
   
     +
   
      i.ToString();

 PCreateCon.Controls.Add(tbx);
 }
 }



 
   
     private
   
      
   
     void
   
      CreateTextBox() 
　　 {
 tbx 
   
     =
   
      
   
     new
   
      TextBox();

 tbx.ID 
   
     =
   
      
   
     "
   
     Tbx
   
     "
   
      
   
     +
   
      Id.ToString();

 PCreateCon.Controls.Add(tbx);
　　 } 
　　 
   
     protected
   
      
   
     void
   
      Page_Load(
   
     object
   
      sender, EventArgs e) 
　　 { 
　　 
   
     if
   
      (
   
     this
   
     .IsPostBack) 
　　 {
 CreateTextBoxListForLoad();
　　 } 
　　 }



 
   
     protected
   
      
   
     void
   
      BtnCreCon_Click(
   
     object
   
      sender, EventArgs e)
 {
 CreateTextBox();
 Id
   
     ++
   
     ;
 }
 
   
     protected
   
      
   
     void
   
      BtnShowMess_Click(
   
     object
   
      sender, EventArgs e)
 {
 LtlShowMess.Text 
   
     =
   
      
   
     ""
   
     ;
 
   
     for
   
      (
   
     int
   
      i 
   
     =
   
      
   
     0
   
     ; i 
   
     <
   
      Id; i
   
     ++
   
     )
 {
 LtlShowMess.Text 
   
     +=
   
      ((TextBox)PCreateCon.FindControl(
   
     "
   
     Tbx
   
     "
   
      
   
     +
   
      i.ToString())).Text;
 }
 }