Private mButtons As List(Of Button)
 
    Public Sub New()
        InitializeComponent()
        Me.mButtons = New List(Of Button)
        Me.mButtons.Add(Button1)
        Me.mButtons.Add(Button2)
        Me.mButtons.Add(Button4)
    End Sub
 
    Private Sub Button1_Click(ByVal sender As System.Object, ByVal e As _
      System.EventArgs) Handles Button1.Click, Button2.Click, Button4.Click
        ButtonBlauFaerben(CType(sender, Button))
    End Sub
 
    Private Sub ButtonBlauFaerben(ByVal button As Button)
        For Each a As Button In Me.mButtons
            If a.Name = button.Name Then
                a.BackColor = Color.Blue
            Else
                a.BackColor = Color.Gray
            End If
        Next
    End Sub