Get value of c# dynamic property via string

Question

I'd like to access the value of a dynamic c# property with a string:

dynamic d = new { value1 = "some", value2 = "random", value3 = "value" };

How can I get the value of d.value2 ("random") if I only have "value2" as a string? In javascript, I could do d["value2"] to access the value ("random"), but I'm not sure how to do this with c# and reflection. The closest I've come is this:

d.GetType().GetProperty("value2") ... but I don't know how to get the actual value from that.

As always, thanks for your help!

Answer 1

Once you have your PropertyInfo (from GetProperty), you need to call GetValue and pass in the instance that you want to get the value from. In your case:

d.GetType().GetProperty("value2").GetValue(d, null);

Answer 2

public static object GetProperty(object target, string name)
{
    var site = System.Runtime.CompilerServices.CallSite<Func<System.Runtime.CompilerServices.CallSite, object, object>>.Create(Microsoft.CSharp.RuntimeBinder.Binder.GetMember(0, name, target.GetType(), new[]{Microsoft.CSharp.RuntimeBinder.CSharpArgumentInfo.Create(0,null)}));
    return site.Target(site, target);
}

Add reference to Microsoft.CSharp. Works also for dynamic types and private properties and fields.

Edit: While this approach works, there is almost 20× faster method from the Microsoft.VisualBasic.dll assembly:

public static object GetProperty(object target, string name)
{
    return Microsoft.VisualBasic.CompilerServices.Versioned.CallByName(target, name, CallType.Get);
}

Answer 3

Dynamitey is an open source .net std library, that let's you call it like the dynamic keyword, but using the a string for the property name rather than the compiler doing it for you, and it ends up being equal to reflection speedwise (which is not nearly as fast as using the dynamic keyword, but this is due to the extra overhead of caching dynamically, where the compiler caches statically).

Dynamic.InvokeGet(d,"value2");