DataList控件里面ASP.NET访问Web控制 [英] ASP.NET Accessing web control inside DataList control

问题描述

我不知道为什么我不能访问这是该小组内我Label控件和面板是在DataList

Am not sure why I cannot access my Label control which was inside the Panel and the Panel is inside the DataList

<asp:DataList ID="DataList2" runat="server" DataSourceID="SqlDataSource1" Width="100%">
<ItemTemplate>
    <table border="0" cellpadding="0" cellspacing="0" width="100%">
        <tr>
            <!-- post details -->
            <td style="width: 60%">
                <asp:Panel ID="panelPostDetails" runat="server" CssClass="postpage_details">
                    <table border="0" cellpadding="5" cellspacing="0" width="100%">
                        <tr>
                            <td colspan="2"><div class="postpage_header"><%# Eval("Heading") %></div></td>
                        </tr>
                        <tr>
                            <td>
                                <img src="picserver/posts/<%# Eval("ImagePath") %>/1.jpg" alt="preview" style="width: 240px;" />
                                <div id="morepictures">
                                    <asp:Label ID="lblMorePictures" runat="server" />
                                </div>
                            </td>
                            <td>
                                <div style="padding: 0px 5px 0px 5px;">
                                    <div>
                                        more stuff here
                                    </div>
                                </div>
                            </td>
                        </tr>
                    </table>
                </asp:Panel>

                <asp:RoundedCornersExtender ID="RoundedCornersExtender1" runat="server" 
                    Radius="6" 
                    Corners="All" 
                    TargetControlID="panelPostDetails"></asp:RoundedCornersExtender>
            </td>
        </tr>
    </table>    

</ItemTemplate>
</asp:DataList>

但是当我在Page_Load中尝试使用LBL，似乎无法找到控制？你能帮帮我吗？

but when I tried using "lbl" in Page_Load, it seems it cannot find the control? can you please help me?

ItemDataBound and Page_Load event
---------------------------------
Panel p = DataList2.FindControl("panelPostDetails") as Panel;
Label l = p.FindControl("lblMorePictures") as Label;
l.Text = code;

这code返回对象引用未设置到对象的实例。

在此先感谢

更新：

ItemDataBound and Page_Load event
---------------------------------
Panel p = DataList2.FindControl("panelPostDetails") as Panel;
if(p==null)
{
     System.Diagnostic.Debug.WriteLine("panel does not exist");
}
else
{
     System.Diagnostic.Debug.WriteLine("panel does exist");
}

output:
panel does not exist

这到底是怎么回事！？！

what on earth is going on!?!

推荐答案

通常情况下，您可以通过处理或者DataList的ItemCreated或者ItemDataBound事件像这样访问控制在运行时。下面是一个示例事件处理程序：

Typically, you access controls like this at runtime by handling either the DataList's ItemCreated or ItemDataBound event. Here's a sample event handler:

protected void DataList2_ItemDataBound(object sender, DataListItemEventArgs e) {
   if (e.Item.ItemType == ListItemType.Item) {
        Label lbl = (Label)e.Item.FindControl("panelPostDetails").FindControl("lblMorePictures");
        lbl.Text = code;
   }
}

线材你的事件处理程序是这样的：

Wire up your the event handler like this:

<asp:DataList ID="DataList2" runat="server" OnItemDataBound="DataList2_ItemDataBound" ...

这篇关于DataList控件里面ASP.NET访问Web控制的文章就介绍到这了，希望我们推荐的答案对大家有所帮助，也希望大家多多支持IT屋！