Convert MVC ViewBag property to lowercase

Question

I'm trying to use a Boolean MVC ViewBag property that is being set in a controller inside of a javascript if statement. However, there is a problem being introduced because the property value gets converted to Pascal case. For example, "true" becomes "True" and "false" becomes "False".

<script type="text/javascript">
    var error = @ViewBag.Dropped;
    if ( error ) {
        $( '#alert-message' ).addClass('alert-success alert-dismissable');
    }
</script>

How can I ensure that the property gets converted to lowercase. I've tried to use javascript function .toLowerCase() and was unsuccessful.

You need to consider whether the property is a string or boolean value. The True value is probably actually a boolean (hence the case) and it gets converted to a string when you assign it in Javascript. — Paul Coldrey, Sep 17 '15 at 22:33
It has nothing to do with upper or lower case. `var error = @ViewBag.Dropped;` returns a text value so `if ( error ) {` will always be evaluated as true - you need `if (error === 'True') {` — , Sep 17 '15 at 22:36
use @Json.Encode(ViewBag.Dropped), it worked for me. I was using bool prop from CS file in JS. — Raj, Aug 05 '16 at 09:46

score 5 · Answer 1 · answered Sep 17 '15 at 22:28

5

One way would be:

<script type="text/javascript">
    var error = @(ViewBag.Dropped ? "true" : "false");
    if ( error ) {
        $( '#alert-message' ).addClass('alert-success alert-dismissable');
    }
</script>

answered Sep 17 '15 at 22:28

Amit

45,440
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score 3 · Answer 2 · answered Sep 17 '15 at 22:31

3

var error = @ViewBag.Dropped.ToString().ToLower();

answered Sep 17 '15 at 22:31

Biff MaGriff

8,102
9
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98

score 1 · Answer 3 · answered Sep 17 '15 at 22:35

1

I don't think the above answer will work since all strings are true in Javascript,.. you might want

<script type="text/javascript">
    var error = @(ViewBag.Dropped ? true : false);
    if ( error ) {
        $( '#alert-message' ).addClass('alert-success alert-dismissable');
    }
</script>

note if you quote true and false they become strings and true is NOT the same as "true".

answered Sep 17 '15 at 22:35

Paul Coldrey

1,389
11
20

You probably didn't understand my answer (that you're referring to). The string is server side (asp, razor...) it gets evaluated and written to the client side without the quotes. – Amit Sep 17 '15 at 22:40
mea culpa - I should have looked more closely :-) – Paul Coldrey Sep 17 '15 at 22:53

score 0 · Answer 4 · answered Sep 18 '15 at 09:28

I use this method all the time because the longer version (value.ToString().ToLowerInvariant()) is too tedious to type all the time:

Add a class to your project or library:

public static class ExtensionMethods
{
    public static string ToJS(this bool value)
    {
        return value.ToString().ToLowerInvariant();
    }
}

then in your js:

<script type="text/javascript">
    var error = @ViewBag.Dropped.ToJS();
    if ( error ) {
        $( '#alert-message' ).addClass('alert-success alert-dismissable');
    }
</script>

Convert MVC ViewBag property to lowercase

4 Answers4