C# If 语句在中继器 ItemTemplate
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If statement in repeaters ItemTemplate
提问by Vivendi
I'm using an ASP.NET Repeaterto display the contents of a <table>. It looks something like this:
我正在使用 ASP.NETRepeater来显示<table>. 它看起来像这样：
<table cellpadding="0" cellspacing="0">
<asp:Repeater ID="checkboxList" runat="server" OnItemDataBound="OnCheckboxListItemBound">
<ItemTemplate>
<tr id="itemRow" runat="server">
<td>
Some data
</td>
</tr>
</ItemTemplate>
</asp:Repeater>
</table>
It works fine, but i'd like to have an if()statement inside the ItemTemplateso i can conditionally determine if i want to print out a <tr>tag.
它工作正常，但我想if()在里面有一个语句，ItemTemplate这样我就可以有条件地确定是否要打印<tr>标签。
So i'd like to have something like this:
所以我想要这样的东西：
<table cellpadding="0" cellspacing="0">
<asp:Repeater ID="checkboxList" runat="server" OnItemDataBound="OnCheckboxListItemBound">
<ItemTemplate>
<% if ( (CurrentItemCount % 2) == 0 ) { %?>
<tr id="itemRow" runat="server">
<% } %>
<td>
Some data
</td>
<% if ( (CurrentItemCount % 2) == 0 ) { %?>
</tr>
<% } %>
</ItemTemplate>
</asp:Repeater>
</table>
Is there some way i can achieve this?
有什么方法可以实现这一目标吗？
PS. The CurrentItemCountis just made up. I also need a way to get the current item count inside that if()statement. But i only seem to be able to get it from <%# Container.ItemIndex; %>, which can't be used with an if()statement?
附注。在CurrentItemCount刚刚组成。我还需要一种方法来获取该if()语句中的当前项目数。但是我似乎只能从 中获取它<%# Container.ItemIndex; %>，不能与if()语句一起使用？
采纳答案by Tim Schmelter
I would use codebehind:
我会使用代码隐藏：
protected void OnCheckboxListItemBound(Object sender, RepeaterItemEventArgs e)
{
if (e.Item.ItemType == ListItemType.Item || e.Item.ItemType == ListItemType.AlternatingItem)
{
HtmlTableRow itemRow = (HtmlTableRow) e.Item.FindControl("itemRow");
itemRow.Visible = e.Item.ItemIndex % 2 == 0;
}
}
回答by Claudio Redi
If you're trying yo make a 2 columns table this could do the trick
如果您正在尝试制作 2 列表，这可以解决问题
<%# Container.ItemIndex % 2 == 0 ? "<tr class='itemRow'>" : "" %>
<td>
Some data
</td>
<%# Container.ItemIndex % 2 != 0 ? "</tr> : "" %>
Changed a couple of things: id="itemRow"for all rows would cause repeated ids what is not allowed.
改变了几件事：id="itemRow"对于所有行会导致重复的 ids 是不允许的。
Removed runat="server"since doesn't make sense on this context.
删除，runat="server"因为在此上下文中没有意义。
回答by Amc Amsterdam - Netherlands
I have 2 examples, for the examples i will bind the repeater to a array of strings (demonstration purposes only)
我有 2 个例子，对于这些例子，我将转发器绑定到一个字符串数组（仅用于演示目的）
void BindCheckboxList()
{
checkboxList.DataSource = new string[] { "RowA", "RowB", "RowC", "RowD", "RowE", "RowF", "RowG" };
checkboxList.DataBind();
}
Example 1: Create a methode in de codebehind casting the bound elements back en evaluate what ever value you'd like.
示例 1：在 de codebehind 中创建一个方法，将绑定的元素投射回去，然后评估您想要的任何值。
Create Methode in CodeBehind (example 1):
在 CodeBehind 中创建 Methode（示例 1）：
protected string StringDataEndsWith(object dataElement, string endsWith, string returnValue)
{
// for now an object of the type string, can be anything.
string elem = dataElement as string;
if (elem.EndsWith(endsWith))
{
return returnValue;
}
else
{
return "";
}
}
In the .aspx file (example 1):
在 .aspx 文件中（示例 1）：
<asp:Repeater ID="checkboxList" runat="server">
<HeaderTemplate>
<table style="padding:0px;margin:0px;">
</HeaderTemplate>
<ItemTemplate>
<%# StringDataEndsWith(Container.DataItem,"A","<tr id=\"itemRow\" runat=\"server\">") %>
<td>
<%# Container.DataItem %>
</td>
<%# StringDataEndsWith(Container.DataItem,"G","</tr>") %>
</ItemTemplate>
<FooterTemplate>
</table>
</FooterTemplate>
</asp:Repeater>
Example 2: You could use a direct cast in the .aspx file
示例 2：您可以在 .aspx 文件中使用直接转换
DirectCast example (no code behind):
DirectCast 示例（后面没有代码）：
<asp:Repeater ID="checkboxList" runat="server">
<HeaderTemplate>
<table style="padding:0px;margin:0px;">
</HeaderTemplate>
<ItemTemplate>
<%# Convert.ToString(Container.DataItem).EndsWith("A") ? "<tr id=\"itemRow\" runat=\"server\">" : "" %>
<td>
<%# Container.DataItem %>
</td>
<%# Convert.ToString(Container.DataItem).EndsWith("G") ? "</tr>" : "" %>
</ItemTemplate>
<FooterTemplate>
</table>
</FooterTemplate>
</asp:Repeater>
I hope this is what you're looking for. Regards.
我希望这就是你要找的。问候。
回答by kduenke
If you're wanting to do something on every other item, use the alternating item template. http://msdn.microsoft.com/en-us/library/system.web.ui.webcontrols.repeater.alternatingitemtemplate.aspx
如果您想对所有其他项目执行某些操作，请使用交替项目模板。 http://msdn.microsoft.com/en-us/library/system.web.ui.webcontrols.repeater.alternatingitemtemplate.aspx
回答by maets
Another way of doing this (if performance is not a problem):
另一种方法（如果性能不是问题）：
<ItemTemplate>
<!-- "If" -->
<asp:PlaceHolder runat="server" Visible="<%# MyCondition %>">
<tr><td></td></tr>
</asp:PlaceHolder>
<!-- "Else" -->
<asp:PlaceHolder runat="server" Visible="<%# !MyCondition %>">
<tr><td></td></tr>
</asp:PlaceHolder>
</ItemTemplate>
