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Public Class IniTextBox
    Inherits System.Windows.Forms.TextBox
 
    Private _IniText As String = ""
 
    Private _IniForeColor As Color = Color.LightGray
    Private _ForeColor As Color = Color.Black
 
    Public Sub New(IniText As String)
        _IniText = IniText
        Me.Text = _IniText
        Me.ForeColor = _IniForeColor
    End Sub
 
    Private Sub RemoveIniText()
        If Me.ForeColor = _IniForeColor Then
            Me.Text = ""
            Me.ForeColor = _ForeColor
        End If
    End Sub
 
    Protected Overrides Sub OnKeydown(e As System.Windows.Forms.KeyEventArgs)
        MyBase.OnKeyDown(e)
        RemoveIniText()
    End Sub
 
    Protected Overrides Sub OnLostFocus(e As System.EventArgs)
        MyBase.OnLostFocus(e)
        If Me.Text = String.Empty Then
            Me.Text = _IniText
            Me.ForeColor = _IniForeColor
        End If
    End Sub
End Class

    Dim tbo As New IniTextBox("Hier etwas eintragen") _
       With {.Parent = Me, .Left = 200, .Width = 200}