ASP.NET直放站评估和演示 [英] ASP.NET Repeater Eval

问题描述

我想在.aspx页面中执行以下code：

I am trying to execute the following code in a .aspx page:

<asp:Repeater ID="rptComentarios" runat="server">
            <ItemTemplate>
                <% if (Convert.ToInt32(Eval("int_tipo")) == 1)
                   { %>
                                        <div class="resp">
            <div class="top">
            </div>
            <div class="cont-resp">
                <h3>
                    <%# Eval("txt_nome") %></h3>
                <p>
                 <%# Eval("txt_comentario") %></p>
            </div>
        </div>
                   <% }
                   else
                   {%>
                               <div class="usuario">
            <div class="top">
            </div>
            <div class="cont-usuario">
                <h3>
                       <%# Eval("txt_nome") %></h3>
                <p>
                    <%# Eval("txt_comentario") %></p>
            </div>
        </div>
                   <% } %>
            </ItemTemplate>
            </asp:Repeater>

它抛出一个运行时异常中的第一行：

It throws a runtime exception in the first line:

  <% if (Convert.ToInt32(Eval("int_tipo")) == 1)

System.InvalidOperationException：数据绑定方法如的eval（），XPath的（）和b​​ind（）只能在数据绑定控件的上下文中使用

System.InvalidOperationException: Databinding methods such as Eval(), XPath() and Bind() can only be used in the context of a databound control.

有什么不对？任何想法？

What's wrong? Any ideas?

推荐答案

我有一个类似的问题，以下code为我工作：

I had a similar problem and the following code worked for me:

<asp:Repeater ID="rptComentarios" runat="server">
  <ItemTemplate>

    <asp:PlaceHolder ID="placeholderBlaBlaBla" runat="server" Visible='<%# Convert.ToInt32(Eval("int_tipo")) == 1 %>'>
      Your optional HTML
    </asp:placeholder>

    Other HTML

  </ItemTemplate>
</asp:Repeater>

一些更多的评论：

Some more comments:

请注意，单引号用于定义值 可见属性ASP：占位符。我试着双引号也和他们没有工作。

Please note that single quotes are used to define the value Visible attribute of asp:placeholder. I tried double quotes too and they didn't work.

任何时候你想要获得一些可选显示HTML您应该使用控件来显示/隐藏它。 ASP：占位符为此工作正常。永远不要做＆LT;％IF（..）{％方式＆gt; - 这是邪恶的。

Anytime you want to get some optionally displayed HTML you should use a control to show/hide it. asp:placeholder works fine for that purpose. Don't ever do <% if(..) { %> - this is evil.

＆LT;％＃......％＆GT; 用于计算和显示前pressions一个中继器内。这些前pressions可以显示为HTML或服务器端控件的属性通过。不能使用如果里面。

<%# ... %> is used to calculate or display expressions inside a repeater. These expressions can be displayed as HTML or passed as attributes of server side controls. You can't use if inside it.

这篇关于ASP.NET直放站评估和演示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！