Question

I am trying to use the following code in a button. I want to call DrawLineFloat. I tried call DrawLineFloat() but it did not work. What do I need to enter in ()?

Thanks

 Public Sub DrawLineFloat(ByVal e As PaintEventArgs)
    ' Create pen.
    Dim blackPen As New Pen(Color.Black, 3)
    ' Create coordinates of points that define line.
    Dim x1 As Single = 100.0F
    Dim y1 As Single = 100.0F
    Dim x2 As Single = 500.0F
    Dim y2 As Single = 100.0F
    ' Draw line to screen.
    e.Graphics.DrawLine(blackPen, x1, y1, x2, y2)
End Sub

Answer 1

I suppose you are calling this inside a form, but not in the Paint event.
So you need to create the Graphics used to draw your line

    Public Sub DrawLineFloat() 
        ' Create pen. 
        Dim blackPen As New Pen(Color.Black, 3) 
        ' Create coordinates of points that define line. 
        Dim x1 As Single = 100.0F 
        Dim y1 As Single = 100.0F 
        Dim x2 As Single = 500.0F 
        Dim y2 As Single = 100.0F 
        ' Draw line to screen. 

        Dim g As Graphics = Me.CreateGraphics()
        g.DrawLine(blackPen, x1, y1, x2, y2) 

        blackPen.Dispose()

End Sub 

Also note that the Pen object should be disposed as soon as possible