C# 'if' key word inside <script> tag in razor view

Question

C# 'if' key word inside <script> tag in razor view

I'm trying to write the following code inside ASP.Net-MVC razor view but the page won't compile.

<script>     

    @(if (Model.IsValid))
     {
        ("#ErrorMessage).text("Error");
     }
    else
    {
       ("#Registration).text("Done!");
    }

</script>

There are workarounds that I did to achieve that operation, but is there a simple way?

2 Answers

Here's a workaround that may look a little better:

<script>
    var modelIsValid = '@ViewData.ModelState.IsValid' == '@true';
    if(modelIsValid)
    {
        $("#ErrorMessage").text("Error");
    }
    else
    {
        $("#Registration").text("Done!");
    }
</script>

Using '@true' makes sure that the true string is always correct (rather than hardcoding it like 'True').

0 Created by Bochu on 2020-03-15 13:32:47 +0000 UTC

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Darin Dimitrov · Accepted Answer · 2020-03-15 13:32:47 +0000 UTC

Try like this:

<script type="text/javascript">
    @if (ViewData.ModelState.IsValid)
    {
        <text>$('#ErrorMessage').text('Error');</text>
    }
    else
    {
        <text>$('#Registration').text('Done!');</text>
    }
</script>

Things to notice:

usage of ViewData.ModelState.IsValid to test if there are modelstate errors
usage of the special <text> to indicate to the razor parser to use the text as is
usage of the $ function as I suppose this is jQuery code
properly closing quotes around javascript strings
usage of the type="text/javascript" attribute on the script tag.