Creating enum at runtime and showing it on a property grid

THEMYTH

Hi coders, I am planning to create an enum at runtime and set it as a property of a class. That is,

Class MyClass
Public Property Type As (New Created Enum)
....
End Class

For creating an enum at runtime I have used the following code

 Public Function CreateEnum() As \[Enum\]
        Dim domain As AppDomain
        domain = Threading.Thread.GetDomain
        Dim name As New System.Reflection.AssemblyName
        name.Name = "EnumCounters"
        Dim asmBuilder As System.Reflection.emit.AssemblyBuilder
        asmBuilder = domain.DefineDynamicAssembly(name, Reflection.Emit.AssemblyBuilderAccess.Run)
        Dim modBuilder As ModuleBuilder
        modBuilder = asmBuilder.DefineDynamicModule("EnumModule")
        Dim enumBuilder As EnumBuilder
        enumBuilder = modBuilder.DefineEnum("EnumCounters", TypeAttributes.Public, GetType(Integer))

'----- HERE IS WHERE I ADD THE ITEMS
For i As Integer = 0 To DiagManager.Counters.Count - 1
enumBuilder.DefineLiteral(CType(DiagManager.Counters(i), Counter).Caption, i)
Next
'-----
Dim enumType As Type = enumBuilder.CreateType
Dim enumObj As [Enum] = System.Activator.CreateInstance(enumType)

        Return enumObj
    End Function

Then, I set my property's value as the returned value of the function. For full code please see (http://emreyazici.com/CodeFormatter.htm -- site does not have banners or advertisement. I only wrote the code) Normally it would work. But when I assign the 'selectedobject' property of 'property grid' to the created instance of class, it does only display the FIRST item of enum in the property grid http://emreyazici.com/res.jpg But I want it to show all items How may I correct it? Thanks...

Best Regards Emre YAZICI

Dave Kreskowiak

Why are you creating an Enum at runtime?? Since an Enum is pretty much only used inside your code, I fail to see the point. You might want to check to see if all the enum values are actually being created. It's possible that your only successfully creating one of them.

Dave Kreskowiak Microsoft MVP - Visual Basic

TwoFaced

I think the problem is that your property returns a general object. Take this code for example. You'll see that the property works fine when I specifically declare it as my enumerator. However, things don't work as well if I make a simple change of declaring the property as an object. I'm not sure how to accomplish what you want but I do know this is why your having a problem.

'Requires a propertygrid
Public Class Form1
Dim test As New TestEnum

Private Sub Form1\_Load(ByVal sender As Object, ByVal e As System.EventArgs) Handles Me.Load
    PropertyGrid1.SelectedObject = test
End Sub

End Class

Public Class TestEnum
Dim _TestMyEnum As MyEnum

'This works just fine because we have declared the property as MyEnum
Public Property TestMyEnum() As MyEnum
    Get
        Return \_TestMyEnum
    End Get
    Set(ByVal value As MyEnum)
        \_TestMyEnum = value
    End Set
End Property

'This returns the exact same enumerator but has been declared as a general object
'The same problem occurs here as you are seeing in your code
Public Property TestMyEnumObject() As Object
    Get
        Return \_TestMyEnum
    End Get
    Set(ByVal value As Object)
        \_TestMyEnum = value
    End Set
End Property

Public Enum MyEnum
    Test0
    Test1
    Test2
End Enum

End Class