How to use ? : if statements with Razor and inline code blocks
I'm updating my old .aspx views with the new Razore view engine. I have a bunch of places where I have code like this:
<span class="vote-up<%= puzzle.UserVote == VoteType.Up ? "-selected" : "" %>">Vote Up</span>
Ideally I'd like to do this:
<span class="vote-up@{puzzle.Us开发者_如何学运维erVote == VoteType.Up ? "-selected" : ""}">Vote Up</span>
However there's two problems here:
vote-up@{puzzle.UserVote
.... is not treating the @ symbol as a start of a code block@puzzle.UserVote == VoteType.Up
looks at the first part@puzzle.UserVote
as if it's supposed to render the value of the variable.
Anyone know how to address these issues?
This should work:
<span class="vote-up@(puzzle.UserVote == VoteType.Up ? "-selected" : "")">Vote Up</span>
@( condition ? "true" : "false" )
The key is to encapsulate the expression in parentheses after the @ delimiter. You can make any compound expression work this way.
In most cases the solution of CD.. will work perfectly fine. However I had a bit more twisted situation:
@(String.IsNullOrEmpty(Model.MaidenName) ? " " : Model.MaidenName)
This would print me " " in my page, respectively generate the source &nbsp;
. Now there is a function Html.Raw(" ")
which is supposed to let you write source code, except in this constellation it throws a compiler error:
Compiler Error Message: CS0173: Type of conditional expression cannot be determined because there is no implicit conversion between 'System.Web.IHtmlString' and 'string'
So I ended up writing a statement like the following, which is less nice but works even in my case:
@if (String.IsNullOrEmpty(Model.MaidenName)) { @Html.Raw(" ") } else { @Model.MaidenName }
Note: interesting thing is, once you are inside the curly brace, you have to restart a Razor block.
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