I pieced together a solution based on [How to evaluate a lambda expression][SO1].

You can [`Compile`][compile] the expression to produce the runnable function inside of it.



    Dim func = lambda.Compile()
    Dim output = func(Me)

---

Since I'm still working my way through lambdas, here's a little more by way of explanation:

Inside the Expression, we declared the function signature to look like this `Func(Of T, Object)`  
When we called the method, we told the function evaluation to behave like this `x => x.Bar.Car`

Compiling will give us a new function, stored as a local variable, that will behave like this:



    Function Anonymous(x as T) As Object
        Return x.Bar.Car
    End

**So we haven't actually passed in the instance at all**.  We've just passed in the definition for what should happen when we call this anonymous function and pass in something of type T.  

So we still need to pull in `Me`. In this case, because this function happens to be sitting inside the same class, we cheated a little since the method already had access to the instance variables.  If it was abstracted out somewhere else, the instance itself would have to be passed in as an additional parameter.


[SO1]: https://stackoverflow.com/q/19992057/1366033
[compile]: http://msdn.microsoft.com/en-us/library/bb345362(v=vs.110).aspx

I'm trying to build a string for a class that contains a list of all it's property names and their respective values for that instance.

Per the question [Get Property Info from an object without giving the property name as string][SO1], I'm getting the property name by using an `Expression` of Type `Func` Of Type `T, Object` like this:



    Private Function GetPropertyValuePair(Of T)(lambda As Expression(Of Func(Of T, Object))) As String
        Dim body As Expression = lambda
    
        'ensure we have the right type of thing
        If TypeOf body Is LambdaExpression Then body = DirectCast(body, LambdaExpression).Body
        If TypeOf body Is UnaryExpression Then body = DirectCast(body, UnaryExpression).Operand
        If body.NodeType <> ExpressionType.MemberAccess Then Throw New InvalidOperationException()
    
        'get property info
        Dim memberInfo = DirectCast(body, MemberExpression).Member
        Dim propInfo = DirectCast(memberInfo, PropertyInfo)
    
        Return propInfo.Name + " - " + propInfo.GetValue(Me, Nothing)
    End Function

In this manner, I'm getting the current value by taking the `PropertyInfo`, and using `GetValue` which searches the current instance for that property.

Then I can call it like this:



    GetPropertyValuePair(Of Foo)(Function(x) x.Bar)

Which will produce:

    Bar - WhateverTheValueIsForBar

**The problem** is when I have is when the property is *nested*, `GetValue` will throw the exception:

> Object does not match target type.

For example, in running the following expression: 

    GetPropertyValuePair(Of Foo)(Function(x) x.Bar.Car)

The property info will be of of type `Car`, which is not found directly on `Foo`.

Can I get the instance value from the original lambda expression without having to do the search with GetValue in the first place?

This is possible with the MVC `@Html.EditorFor` helper, so there must be some mechanism for delivering the value of the passed in function for something like this:

    @Html.EditorFor(Function(model) model.Bar.Car)

Any Ideas?

[SO1]: https://stackoverflow.com/q/16777292/1366033