以下“FindControl”方法无法找到 imgAd 控件。知道为什么吗?可能是包含它的表吗?表格的目的是跨行按列排列。
<asp:Content ID="Content3" ContentPlaceHolderID="phPageContent" runat="Server">
<asp:Repeater ID="repBanner" runat="server">
<HeaderTemplate>
<table>
</HeaderTemplate>
<ItemTemplate>
<tr>
<td>
<asp:Image ID="imgAd" runat="server" AlternateText="Panda Visa" ImageUrl="Images/AffiliateBanners/125%20by%20125.jpg" />
</td>
<td>
<asp:TextBox ID="txtHtml" runat="server" Columns="80" ReadOnly="True" Rows="7" TextMode="MultiLine"></asp:TextBox>
</td>
<td>
<asp:Button runat="server" Text="Copy HTML to Clipboard" OnClientClick="ClipBoard('txtHtml')" />
</td>
</tr>
</ItemTemplate>
<FooterTemplate>
</table>
</FooterTemplate>
</asp:Repeater>
Protected Sub repBanner_ItemDataBound(ByVal sender As Object, ByVal e As System.Web.UI.WebControls.RepeaterItemEventArgs) Handles repBanner.ItemDataBound
Dim CurrentAd As Ad = CType(e.Item.DataItem, Ad)
Dim RepeaterItem As RepeaterItem = e.Item
Dim imgAd As Image = CType(RepeaterItem.FindControl("imgAd"), Image)
imgAd.ImageUrl = "Images/" & "125 by 125.jpg" '<<<Error occurs here
End Sub
Object reference not set to an instance of an object.
这是一些我认为可能会有所帮助的调试信息:
? RepeaterItem.Controls.Count
1
? RepeaterItem.Controls(0).Controls.Count
0
? typename(RepeaterItem.Controls(0))
"LiteralControl"