What is PHP's isset equivalent in c# .NET 4 for properties of 'dynamic' objects?

Question

I am working with MVC 3 at the moment where I use the ViewBag. I would like to test if one of the properties of the ViewBag has been assigned. I know in PHP you could do isset(variable), but is there something similar in .NET 4?

The scenario is that I am making a nested layout which takes a section title and a section subtitle through the ViewBag. They are seperated by a seperator and the sub title is optional. I don't want to display the seperator if the sub title is not set.

This is how I imagine it where isset would be replaced by the .NET 4 equivelant.

@section header 
{
    <h2>@ViewBag.SectionTitle</h2>
    @if(isset(ViewBag.SectionSubTitle)) 
    { 
        <div id="section-title-seperator"> - </div><h3>@ViewBag.SectionSubTitle</h3> 
    }
}

Next to the direct answer to my question, I'm also open to alternate solutions (in case I'm abusing the ViewBag).

Thanks in advance.

Answer 1

You can check if it is null like this:

@if(ViewBag.SectionSubTitle != null).

isset() in PHP actually just checks if there is a value present. From the manual:

isset() will return FALSE if testing a variable that has been set to NULL

You can also use ViewDataDictionary.ContainsKey on your ViewData property. Because ViewData["SectionSubTitle"] is equavilient to ViewBag.SectionSubTitle so in this case you could do:

@if(ViewData.ContainsKey("SectionSubTitle"))