.NET嵌套中繼器 - 按鈕點擊調用OnItemCreated eventhandler，而不是OnItemCommand

Question

我有一個簡單的嵌套中繼器的項目。當我點擊按鈕時，OnItemCommand事件不被調用，但OnItemCreated被調用（但是，它不調用Page_Load事件處理程序）。我在誤解什麼？

MARKUP

<table width="100%"> 
    <tr> 
     <td>my row</td> 
     <td>my description</td> 
    </tr> 
    <asp:Repeater ID="rptMain" runat="server" OnItemCreated="rptMain_ItemCreated" OnItemCommand="rptMain_ItemCommand"> 
     <ItemTemplate> 
     <tr style="background-color:#45abdc;"> 
      <td><asp:LinkButton ID="ibtnDoSomething" runat="server" CommandArgument="SELECT" Text="Clicky" /></td> 
      <td><asp:Label ID="lblMainData" runat="server"></asp:Label></td> 

     </tr> 
     <asp:Repeater ID="rptChild" runat="server" OnItemCreated="rptChild_ItemCreated"> 
      <ItemTemplate> 
       <tr style="background-color:#bcbbcb;"> 
        <td> 

        </td> 
        <td> 
         <asp:Label ID="lblChildData" runat="server"></asp:Label> 
        </td> 

       </tr> 

      </ItemTemplate> 
     </asp:Repeater> 
     </ItemTemplate> 
    </asp:Repeater> 

    </table> 

代碼隱藏 的DataTable _childdata =新數據表（）; DataTable _data = new DataTable（）;

 public void Page_Load() 
     { 

      _data.Columns.Add(new DataColumn("Text")); 
      _data.Columns.Add(new DataColumn("CommandValue")); 

      DataRow _row1 = _data.NewRow(); 
      _row1["Text"] = "Butch"; 
      _row1["CommandValue"] = "31"; 
      DataRow _row2 = _data.NewRow(); 
      _row2["Text"] = "Karl"; 
      _row2["CommandValue"] = "2"; 
      DataRow _row3 = _data.NewRow(); 
      _row3["Text"] = "Suzie"; 
      _row3["CommandValue"] = "8"; 
      DataRow _row4 = _data.NewRow(); 
      _row4["Text"] = "Kara"; 
      _row4["CommandValue"] = "31"; 

      _data.Rows.Add(_row1); 
      _data.Rows.Add(_row2); 
      _data.Rows.Add(_row3); 
      _data.Rows.Add(_row4); 




      _childdata.Columns.Add(new DataColumn("Text")); 
      _childdata.Columns.Add(new DataColumn("CommandValue")); 

      DataRow _crow1 = _childdata.NewRow(); 
      _crow1["Text"] = "Butch"; 
      _crow1["CommandValue"] = "Cupcakes"; 
      DataRow _crow2 = _childdata.NewRow(); 
      _crow2["Text"] = "Karl"; 
      _crow2["CommandValue"] = "Cheese"; 
      DataRow _crow3 = _childdata.NewRow(); 
      _crow3["Text"] = "Suzie"; 
      _crow3["CommandValue"] = "Pizaa"; 
      DataRow _crow4 = _childdata.NewRow(); 
      _crow4["Text"] = "Kara"; 
      _crow4["CommandValue"] = "Tofu"; 
      DataRow _crow5 = _childdata.NewRow(); 
      _crow5["Text"] = "Butch"; 
      _crow5["CommandValue"] = "Bacon"; 
      DataRow _crow6 = _childdata.NewRow(); 
      _crow6["Text"] = "Karl"; 
      _crow6["CommandValue"] = "Ham"; 

      _childdata.Rows.Add(_crow1); 
      _childdata.Rows.Add(_crow2); 
      _childdata.Rows.Add(_crow3); 
      _childdata.Rows.Add(_crow4); 
      _childdata.Rows.Add(_crow5); 
      _childdata.Rows.Add(_crow6); 

      rptMain.DataSource = _data; 
      rptMain.DataBind(); 

     } 

     public void rptMain_ItemCreated(object sender, RepeaterItemEventArgs e) 
     { 

      if (e.Item.ItemType == ListItemType.Item || e.Item.ItemType == ListItemType.AlternatingItem) 
      { 
       DataRowView drv = (DataRowView)e.Item.DataItem; 

       LinkButton ibtn = e.Item.FindControl("ibtnDoSomething") as LinkButton; 
       Label mainLabel = e.Item.FindControl("lblMainData") as Label; 
       ibtn.CommandArgument = drv["CommandValue"].ToString(); 
       mainLabel.Text = drv["Text"].ToString(); 
       DataView _dv = new DataView(_childdata, "Text = '" + drv["Text"].ToString() + "'", "Text", DataViewRowState.CurrentRows); 
       Repeater _rptChild = e.Item.FindControl("rptChild") as Repeater; 
       _rptChild.DataSource = _dv; 
       _rptChild.DataBind(); 
      } 

     } 

     public void rptChild_ItemCreated(object sender, RepeaterItemEventArgs e) 
     { 
      if (e.Item.ItemType == ListItemType.Item || e.Item.ItemType == ListItemType.AlternatingItem) 
      { 

       Label childLabel = e.Item.FindControl("lblChildData") as Label; 
       DataRowView drv = (DataRowView)e.Item.DataItem; 
       childLabel.Text = drv["Text"].ToString(); 

      } 
     } 

     public void rptMain_ItemCommand(object sender, RepeaterCommandEventArgs e) 
     { 
      Console.Write("fdasdfsa"); 
     } 

Answer 1

中繼器將在回發期間重新創建。這就是OnItemCreated事件觸發的原因。 OnItemCommand未被調用的原因是因爲您的OnItemCreated事件中發生異常。該物業

e.Item.DataItem 

不可用於回發並返回null。因此，當您嘗試訪問它時，您會遇到一個NullReferenceException。

ibtn.CommandArgument = drv["CommandValue"].ToString(); 

您最終得到NullReferenceException。

Answer 2

你需要在你的linkbutton控件上指定一個CommandName屬性嗎？

Answer 3

這個工作對我停止Item_Created

protected void On_Item_Created(Object sender, DataListItemEventArgs e) 
{ 
    if (!Page.IsPostBack) 
    { 
     //Do stuff 
    } 
}