How to read a property of an anonymous type?

Question

I have a method that returns

return new  System.Web.Mvc.JsonResult()
{                     
    Data = new
    {
        Status = "OK", 
    }
}

I need to write a unit test where I need to verify that jsonResult.Data.status= "OK".

How do I read the status property?

Update: I tried the [assembly: InternalsVisibleTo("TestingAssemblyName")], but that didn't help. I kept getting the error {"'System.Web.Mvc.JsonResult' does not contain a definition for 'Status'"}

Besides I think I will prefer not modifying the code that I am testing.

So I took Jon's advice and used reflection.

        var type = jsonResult.Data.GetType();

        var pinfo = type.GetProperty("Status");

        string  statusValue = pinfo.GetValue(jsonResult.Data,null).ToString();

        Assert.AreEqual("OK", statusValue);

If you are doing this from C#, you could just use `dynamic` and let the dynamic binder take care of it. — vcsjones, Dec 20 '12 at 22:18
gallio unit test. What I am trying is Assert.AreEqual("OK", jsonResult.Data.Status) — developer747, Dec 20 '12 at 22:18

score 18 · Accepted Answer · answered Dec 20 '12 at 22:18

The simplest approach would probably be to use dynamic typing:

dynamic foo = ret.Data;
Assert.AreEqual("OK", foo.status);

Note that you'll need to use [InternalsVisibleTo] in order to give your unit test assembly access to the anonymous type in your production assembly, as it will be generated with internal access.

Alternatively, just use reflection.

score 6 · Answer 2 · answered Dec 20 '12 at 22:19

6

dynamic:

dynamic testObject = YourMethodThatReturnsDynamicObject().Data;
Assert.AreEqual("OK", testObject.Status);

answered Dec 20 '12 at 22:19

Simon Whitehead

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The expected value should be the first argument to `AreEqual`, and the actual value should be the second. – Jon Skeet Dec 20 '12 at 22:20
@JonSkeet .. there you go, although as I was typing it I just didn't think (sometimes intellisense goes a long way!). – Simon Whitehead Dec 20 '12 at 22:22
@ AnonymousVoter: I appreciate the sympathy vote.. difficult to get any when you reply at the same time as Jon! :) – Simon Whitehead Dec 20 '12 at 22:50

How to read a property of an anonymous type?

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