Zitat:

This property supports the .NET Framework infrastructure and is not intended to be used directly from your code. Gets or sets a value indicating whether the height of the control automatically adjusts when the font assigned to the control is changed. This property is not relevant for this class.

    Private Sub formMain_Load(ByVal sender As System.Object, _
              ByVal e As System.EventArgs) Handles MyBase.Load
        Dim box As New mybox()
        box.AutoSize = True
        Me.Controls.Add(box)
    End Sub
 
    Class mybox
        Inherits TextBox
        <Browsable(True), Description("Beschreibung bla"), Category( _
          "Appearance")> _
        Public Overrides Property AutoSize() As Boolean
            Get
                Return MyBase.AutoSize
            End Get
            Set(ByVal value As Boolean)
                MyBase.AutoSize = value
            End Set
        End Property
    End Class