Cast anonymous types

Today, when coding for one module in my project at company, I had a problem that make me crazy. Used var keyword on .NET 3.5, it's a anonymous type, so when we go out its scope, we don't know its type. I think many people also had this problem like me. So after using many methods for solve this problem, I also found the best solution for it. Thanks Alex for best idea from him! Now there are some my effort for solve it:
+ First thing, I tried to coding and gave this error:
                 Cannot cast 'exampleObj' (which has an actual type of '<>f__AnonymousType0<string,string>') ...
+ Next, I started my working for solving it. Wrote the extension method for cast anonymous method:

public static class Extender
{
 public static T Cast(this object obj, T what)
        {
            return (T)obj;
        }
}

+ Object that content the anonymous type:

var exampleObj = from node in rootNode.Descendants()
                 where node.FirstAttribute != null && node.FirstAttribute.Value == "ExampleName"
                 select new
                 {
                  FirstField = node.FirstAttribute.Value,
                        SecondField = node.LastAttribute.Value
                 };

Binding this object to ListView:

exampleObj .All(x =>
 {
 lstView.Items.Add(x);
        lstView.ValueMember = "FirstField ";
        lstView.DisplayMember = "SecondField ";
        return true;
 });

+ And used the extension method for cast anonymous type:

var exampleObj= lstView.SelectedItem;
var castObj = exampleObj.Cast(new { 
               FirstField = "", SecondField = ""
           });

Now we can use it very normally:

var firstField = castObj.FirstField;
var secondField = castObj.SecondField;

+ References:
http://blogs.msdn.com/b/alexj/archive/2007/11/22/t-castbyexample-t-object-o-t-example.aspx?wa=wsignin1.0
http://msdn.microsoft.com/en-us/library/bb383973.aspx
http://msdn.microsoft.com/en-us/library/system.windows.forms.listview.aspx