查找控件问题

Question

我有一个关于 FindControl 的问题。我在中继器中使用 ASPxRoundPanel（带有 DXperience 组件）。我在 ASPxRoundPanel 中有一个名为“txtAdet ID”的文本框。我只是无法访问文本框内部。并且出现以下错误。

"Object reference not set to an instance of an object." 

ascx。代码：

<asp:Repeater ID="Repeater1" runat="server" DataSourceID="urunLinq"
    onitemcommand="Repeater1_ItemCommand">
<ItemTemplate>

    <dxrp:ASPxRoundPanel ID="ASPxRoundPanel1" runat="server" Width="980px" ShowHeader="true" Height="550px">
   <PanelCollection>
   <dxrp:PanelContent>
   <div style="width:980; overflow:hidden;height:350px;">
   <div style="float:left; width:410px;height:310px;">
    <asp:Image ID="Image1" Width="400" Height="300" ImageUrl='<%# "../urunResim/"+Eval("urunAnaResim") %>' runat="server" />
</div>
<div style="float:left;margin-top:0px;overflow:hidden;width:500px;">
<h2><%# Eval("urunAdi") %></h2>

<h4>Ürün Özellikleri</h4>
<p style="font-size:x-small;"><%# Eval("urunOzellikleri") %></p>
<br />
<table>
<tr>
<td><h5>Adet    </h5></td><td><asp:TextBox ID="txtAdet" Width="50" runat="server"></asp:TextBox></td>
<td><h4>        Peşin Fiyatı :</h4></td><td><h3 style="color:Red;">  <%# Eval("kdvliFiyat") %>TL</h3></td>
</tr>
</table>
<br />
<table>
<tr>
<td><a href="#">İnternet satış taksitlerini görmek için tıklayın.</a></td>
<td>                
<asp:ImageButton ID="ImageButton1" CommandName="sepeteKaydet" runat="server" ImageUrl="~/img/icons/sepeteEkle.JPG" /></td>
</tr>
</table>
</div></div>

   </dxrp:PanelContent>
   </PanelCollection>
   <HeaderTemplate>
   <h3><%# Eval("urunAdi") %></h3>
   </HeaderTemplate>
    </dxrp:ASPxRoundPanel>

</ItemTemplate>
</asp:Repeater> 

.cs 代码：

protected void Repeater1_ItemCommand(object source, RepeaterCommandEventArgs e)
        {
            if (e.CommandName=="sepeteKaydet")
            {
               TextBox bulunanTextKontrol = ((TextBox)e.Item.FindControl("txtAdet"));
               string urunAdet = bulunanTextKontrol.Text;
               string sessionId = Session.SessionID;
               int urunId=Convert.ToInt32(Request["id"].ToString());
               tempSepet geciciSepet = new tempSepet()
               {
                    adet = Convert.ToInt32(urunAdet),
                    eklemeSaati = Convert.ToString(DateTime.Now.Hour.ToString()),
                    eklemeTarihi = Convert.ToString(DateTime.Now.ToShortDateString()),
                    sessionId = sessionId,
                    urunId = urunId
               };
               selcukData.tempSepets.InsertOnSubmit(geciciSepet);
               selcukData.SubmitChanges();
               Response.Write("<script type='text/javascript'>alert('Ürün sepetinize başarıyla eklendi')</script>");
               ((TextBox)e.Item.FindControl("txtAdet")).Text = null;
            }
        } 

我在以下行中收到错误。

 string urunAdet = bulunanTextKontrol.Text;

Answer 1

ASPxRoundPanel 控件是 ASPxWebControl 的子类，它实现 INamingContainer 接口。这意味着调用任何父控件（在您的情况下为 RepeaterItem）的 FindControl 将无法在 ASPxRoundPanel 中找到任何内容（解释 此处）。因此，您至少需要两个步骤来完成任务：

ASPxRoundPanel1 roundPanel =  ((ASPxRoundPanel1)e.Item.FindControl("ASPxRoundPanel1"));
TextBox bulunanTextKontrol = ((TextBox)roundPanel.FindControl("txtAdet"));