OnClick Events的回傳問題

Question

但是，我有下面的代碼工作正常，當我點擊刪除按鈕事件觸發但更改不顯示回發。這顯然與PostBack managemment有關。有沒有人有什麼建議？

namespace WebApplication1 
    { 
     public partial class questiondetails : System.Web.UI.Page 
     { 
     protected void Page_Load(object sender, EventArgs e) 
     { 
      if (!IsPostBack) 
      { 
       LoadControls(); 
      } 

     } 

     void Edit_Click(object sender, ImageClickEventArgs e) 
     { 
      ImageButton editbut = sender as ImageButton; 
      string cName = editbut.ID; 
      string rID = cName.Remove(0, 5); 

      Response.Write(Request.Form["entity_" + rID]); 
      Response.Write(Request.Form["dollar_" + rID]); 

     } 

     void Delete_Click(object sender, ImageClickEventArgs e) 
     { 
      var delbut = (ImageButton)sender; 
      string cName = delbut.ID; 
      string rID = cName.Remove(0, 7); 
      string MyParams = "@RowID=" + rID; 

      iservices.DataAccessWebService WS = new iservices.DataAccessWebService(); 

      WS.ExecuteDatasetStoredProcedure(ConfigurationManager.AppSettings["SecurityDataAccess"], "iweb_sp_custom_coi_Question_Delete", MyParams.ToString()); 
      LoadControls(); 
      Response.Write("dome"); 
     } 


     protected void LoadControls() 
     { 

      //Construct paramters from Querystring 
      StringBuilder MyParams = new StringBuilder(); 
      MyParams.Append("@Term=2013,@ProjectCode=a12345,@ID=123,@CategoryCode=CONSULTANCIES"); 

      //Count Answered questions 
      iservices.DataAccessWebService WS = new iservices.DataAccessWebService(); 
      DataSet MyAnswers = WS.ExecuteDatasetStoredProcedure(ConfigurationManager.AppSettings["SecurityDataAccess"], "iweb_sp_custom_coi_SelectCurrentQuestion", MyParams.ToString()); 



      foreach (DataTable dt in MyAnswers.Tables) 
      { 
       int rc = 0; 

       foreach (DataRow dr in dt.Rows) 
       { 

        //Generate unique controls from DS 
        TextBox tbx = new TextBox(); 
        tbx.ID = "entity_" + dr["rowID"].ToString(); 
        tbx.Text = dr["EntityName"].ToString(); 
        tbx.Width = 200; 

        DropDownList DollarRange = new DropDownList(); 
        DollarRange.Items.Add("Select Dollar Amount"); 
        DollarRange.Items.Add("Up to $1,000"); 
        DollarRange.Items.Add("$1,001 - 5,000"); 
        DollarRange.Items.Add("$5,001 - $10,000"); 
        DollarRange.Items.Add("$10,001 - $50,000"); 
        DollarRange.Items.Add("$50,001 - or more"); 
        DollarRange.ID = "dollar_" + dr["rowID"].ToString(); 
        DollarRange.SelectedValue = dr["DollarRange"].ToString(); 

        ImageButton Delete = new ImageButton(); 
        Delete.ImageUrl = "delete.png"; 
        Delete.ID = "delete_" + dr["rowID"].ToString(); 
        Delete.Click += Delete_Click; 

        ImageButton Edit = new ImageButton(); 
        Edit.ImageUrl = "edit.png"; 
        Edit.ID = "edit_" + dr["rowID"].ToString(); 
        Edit.Click += Edit_Click; 

        //Append controls to placeholder 
        DataZone.Controls.Add(new LiteralControl((rc % 2 == 0) ? "<tr><td bgcolor='#f1f0e7'>" : "<tr><td>")); 
        DataZone.Controls.Add(tbx); 
        DataZone.Controls.Add(new LiteralControl((rc % 2 == 0) ? "</td><td bgcolor='#f1f0e7'>" : "</td><td>")); 
        DataZone.Controls.Add(DollarRange); 
        DataZone.Controls.Add(new LiteralControl((rc % 2 == 0) ? "</td><td bgcolor='#f1f0e7'>" : "</td><td>")); 
        DataZone.Controls.Add(Delete); 
        DataZone.Controls.Add(Edit); 
        DataZone.Controls.Add(new LiteralControl("</td></tr>")); 
        rc++; 
       } 



      } 

     } 
    } 
} 

Answer 1

代碼的問題是，如果它不是PostBack，則不執行LoadControls。當你動態地添加新的控件時，它會在頁面內註冊，所以當回調控件時會被調用 - 頁面會知道它應該調用什麼方法。

在你的情況下，當PostBack發生時，你不會調用LoadControls，所以Page不知道它應該調用什麼方法，因爲在頁面搜索控件處理當前回發數據時沒有控制。

如果你每次都會做LoadControls而不檢查PageLoad中的IsPostBack，那麼Delete_Click方法將會被調用。但是可能會對數據做兩次請求 - 一次是在PageLoad中進行控件填充，另一次是在Delete_Click方法中刪除和更新新數據。

沒有您的另一個代碼的時刻 - 你正在將控件添加到數據區，我想是ASP：佔位符，但你並不清楚，所以控制可以複製的第二LoadControls調用。像往常一樣，在更新數據之前需要清除PlaceHolder。