Very simple way to move a form holding down mouse button

Public Class Form1
    Dim pastx, pasty, presentx, presenty, bt As Integer

    Sub moving()
        Dim xx, yy As Integer
        xx = presentx - pastx
        yy = presenty - pasty
        If bt Then 'set your condition: left btn or right btn or mid btn
            Me.Left = Me.Left + xx
            Me.Top = Me.Top + yy
        End If
    End Sub

    Private Sub Form1_MouseDown(ByVal sender As Object, ByVal e As System.Windows.Forms.MouseEventArgs) Handles Me.MouseDown
        pastx = e.X
        pasty = e.Y
    End Sub

    Private Sub Form1_MouseMove(ByVal sender As Object, ByVal e As System.Windows.Forms.MouseEventArgs) Handles Me.MouseMove
        presentx = e.X
        presenty = e.Y
        bt = e.Button
        moving()
    End Sub
End Class