ASP.NET MVC Client Model and JavaScript

Question

I am curious how to handle setting nullable model information on an aspx page to a JavaScript variable. I am using MVC3 RC, and I am sure this is trivial and I am missing something.

Given this code (again, in my aspx view):

var myFloat = <%: Model.MyNullableFloat %>;

if SelectedAudience is null, what gets written to the page is:

var myFloat = ;

What I want to get written is:

var myFloat = null;

Currently, I have some ugly logic:

    var myFloat = null;
    <%
        if(Model.MyNullableFloat != null) {
    %>
            myFloat = <%: Model.AdGroup.MyNullableFloat %>;
    <%
        }
    %>

Any thoughts on a cleaner way?

Thanks

hunter · Accepted Answer · 2010-12-21 17:30:41Z

3

You can use a conditional operator

var myFloat = <%: Model.MyNullableFloat.HasValue
    ? Model.MyNullableFloat.Value.ToString() 
    : "null"%>;

Remember that both conditions need to return the same type so you'll have to ToString() the result if you want to return "null".

edited Dec 21, 2010 at 17:30

answered Dec 21, 2010 at 17:25

hunter

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Comments

Anonymous Apple · Accepted Answer · 2010-12-21 17:26:21Z

1

Use Ternary operator for a quick solution:

var myFloat = <%: Model.MyNullableFloat.HasValue ? Model.MyNullableFloat.Value : "null"  %>;

answered Dec 21, 2010 at 17:26

Anonymous Apple

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1 Comment

hunter Over a year ago

you'll need to ToString() the value otherwise that will throw an exception

Paul Creasey · Accepted Answer · 2010-12-21 17:32:59Z

1

It's not much better..!

<%= Model.MyNullableFloat.HasValue? Model.MyNullableFloat.ToString() : "null"%>;

or you could try an extension method

public static string ToStringVerboseNull(this float? myFloat)
{
    return myFloat.HasValue ? myFloat.ToString() : "null";
}

and then

<%= myFloat.ToStringVerboseNull()%>

edited Dec 21, 2010 at 17:32

answered Dec 21, 2010 at 17:27

Paul Creasey

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Comments

John Hartsock · Accepted Answer · 2010-12-21 17:37:59Z

1

var myFloat = <%= Model.MyNullableFloat != null ? Model.MyNullableFloat.ToString() : "null" %>;

You could also handle this in your Controller

Public Class MyModel {
  public string MyNullableFloatAsString { get; set; }
}

Public ActionResult Something () {
  MyModel MyControllerModel;

  MyControllerModel.MyNullableFloatAsString = Model.MyNullableFloat != null ? Model.MyNullableFloat.ToString() + ";" : "null;"

  //Return Model to view
}

Now in your View you can simply do this

var myFloat = <%= Model.MyNullableFloatAsString %>

edited Dec 21, 2010 at 17:37

answered Dec 21, 2010 at 17:24

John Hartsock

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1 Comment

hunter Over a year ago

don't you have to ToString() the nullable float?

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