RadMenuItem inheritance display issue

[Constantinos Petridis]

I am trying to inherit RadMenuItem (sample bellow), in order to add more properties required by our application.

Public Class TestMenuItem
    Inherits RadMenuItem

    Public Sub New()
        Me.New("", Nothing)
    End Sub

    Public Sub New(ByVal text As String)
        Me.New(text, Nothing)
    End Sub

    Public Sub New(ByVal text As String, ByVal tag As Object)
        MyBase.New(text, tag)
    End Sub
End Class

When I try to add this new RadMenuItem in a RadMenu object, the visual display of the item is different from the actual RadMenuItem. I guess it is a ThemeEngine glitch. Do you have any advice on how to correctly inherit RadMenuItem?

This is a sample form where two menu items are added, one standard RadMenuItem (test1) and one from the inherited TestMenuItem (test2). Form1 has a RadMenu control added and it is a standard Windows.Form form.

Public Class Form1

    Private Sub Form1_Load(ByVal sender As System.Object, ByVal e As System.EventArgs) Handles MyBase.Load
        Dim mi1 As New RadMenuItem("test1")
        Dim mi2 As New testMenuItem("test2")
        Me.RadMenuItem1.Items.Add(mi1)
        Me.RadMenuItem1.Items.Add(mi2)
    End Sub
End Class

In the attached image you can see the resulting runtime form with the difference in visual display of the two menu items.

We are currently evaluating your WinForms controls and we have little to no experience with your libraries :).

[Deyan]

Hello Constantinos,

Thanks for contacting us and for your interest in RadControls for WinForms.

Indeed, the issue that you experience is related to the theming mechanism. Our theming mechanism maps the XML styles to the elements by using their type. So, by inheriting from RadMenuItem, you introduce a new item type which is not recognizable by our mechanism. Thus, you will have to override the ThemeEffectiveType property in your new RadMenuItem type and return the type of RadMenuItem. Take a look at the code snippet below:

Protected Overrides ReadOnly Property ThemeEffectiveType() As Type
    Get
        Return GetType(RadMenuItem)
    End Get
End Property

Without this property override, your item will remain unstyled by having the default border and fill colors.

Consider this as a general approach of avoiding theming issues when inheriting from different items in our framework.

I hope this helps and will be happy to address any future inquiries regarding our control suite that you might have.

Greetings,
Deyan
the Telerik team

[Constantinos Petridis]

Thank you for your quick answer
It worked like a charm :)