Question

I’m digging into Reflection for the first time and I’m truely stuck. I’ve googled everything I can think of. I’m 90% where I wanna be now.

I’m trying to return the value of a Property in a custom class through Reflection.

Here’s my class declaration:

Public Class Class2     Private newPropertyValue2 As String      Public Property NewProperty2() As String         Get             Return newPropertyValue2         End Get         Set(ByVal value As String)             newPropertyValue2 = value         End Set     End Property    End Class 

The class I’ve written to look at the class through reflection looks like this:

Public Class ObjectCompare     Private _OriginalObject As PropertyInfo()      Public Property OriginalObject() As PropertyInfo()         Get             Return _OriginalObject         End Get         Set(ByVal value As PropertyInfo())             _OriginalObject = value         End Set     End Property      Public Sub CompareObjects()         Dim property_value As Object          For i As Integer = 0 To OriginalObject.Length - 1             If OriginalObject(i).GetIndexParameters().Length = 0 Then                 Dim propInfo As PropertyInfo = OriginalObject(i)                  Try                     property_value = propInfo.GetValue(Me, Nothing)                 Catch ex As TargetException                 End Try                End If         Next     End Sub End Class 

I put a breakpoint on the property_value = propInfo.GetValue(Me, Nothing) line to see what the result is.

Here’s how I call my code:

Dim test As New Class2 test.NewProperty2 = '2'  Dim go As New ObjectCompare Dim propInf As PropertyInfo() propInf = test.GetType.GetProperties()  go.OriginalObject = propInf  go.CompareObjects() 

Through reflection I can see the PropertyName and Type, all I need is the value of the Property! Now when I get to the breakpoint, I get a TargetException and the error message says ‘Object does not match target type.’ Its now 1AM in the morning and I’m wrecked, any help right now would be appreciated. I’ve searched MSDN and Google to death and then on last time for fun 😉

Answer 1

Me refers to the ObjectCompare object, which is different than the class from which the PropertyInfo objects were derived (Class2). You need to also pass in an object of the type from which you retrieved the PropertyInfo objects.

Public Sub CompareObjects(ByVal It as Object)     Dim property_value As Object      For i As Integer = 0 To OriginalObject.Length - 1         If OriginalObject(i).GetIndexParameters().Length = 0 Then             Dim propInfo As PropertyInfo = OriginalObject(i)              Try                 property_value = propInfo.GetValue(It, Nothing)             Catch ex As TargetException             End Try            End If     Next End Sub  go.CompareObjects(test)