#Eval if statement in repeater

问题

I'm trying to check a string value inside a repeater, and if it has value then write a link, but can't seem to get it to work. If there is a value in myUrl then I want to display the link.

 <%if( %> <%#Eval("myURL").ToString().Length > 0 %>
       <a  title="myTitle" target="_blank" href="<%# Eval("myURL") %>">my link</a>                  
 <% } %>

Can anyone please help?

回答1:

try this code !!!

<%#Eval("myURL").ToString().Length > 0 ?
"<a  title='myTitle' target='_blank' href='<%# Eval("myURL") %>'>my link</a>":""%>

回答2:

I personally hate using conditional logic like that in the page.

There are two options that I think are better. You could have a Hyperlink control in the repeater - and set the visibility depending on if the myURL param is there.

visibility='<% #Eval("myURL").ToString().Length > 0 %>'

OR what you can do is have a method on your code behind that you call back to with the "myURL" param.

E.g.

public string CreateURL(string myURL){
    if(!string.IsNullOrEmpty(myURL)){
       return "<a ... ";
    }

    return string.Empty;
}

And call in ASPX

<%# CreateURL(Eval("myURL").ToString()) %>

NB this is untested code but this is the ways I usually do this sort of thing.

回答3:

I would use the String.Format and include the HTML as part of the string. Admittedly, it's not the neatest piece of code ever written, but in my opinion it's the best option:

For example the below will output an anchor tag if the property Url exists, otherwise it will output a span.

<%# string.Format(Eval("Url") != null ? "<a href=\"{0}\">{1}</a>" : "<span>{1}</span>", Eval("Url"), Eval("Text")) %>">

回答4:

Try adding a runat="server" and then add a script block for the (new) server-side visible property:

 <a  title="myTitle" target="_blank" href="<%# Eval("myURL") %>" runat="server" visible='<%#Eval("myURL").ToString().Length > 0 %>'>my link</a>

回答5:

this will help
How do I run an if statement in aspx?
http://forums.asp.net/t/1254412.aspx/1
http://forums.asp.net/t/1161705.aspx

回答6:

You can also call your public function inside code behind file:

<%# MyFunction(Eval("myURL").ToString().Length) %>

来源：https://stackoverflow.com/questions/9289917/eval-if-statement-in-repeater

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