Drawing line in vb.net

Without seeing more of your code, it's hard to see where you're going wrong.

Basically, you're going to need to handle the "Paint" event for your button. When you do that, you'll be able to paint your text, borders, etc. As an example below, this simple button will handle the Paint event, and call your routine.

Public Class MyButton
    Inherits Button

    Private Sub MyButton_Paint(sender As Object, e As System.Windows.Forms.PaintEventArgs) Handles Me.Paint
        DrawLineFloat(e)
    End Sub

    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
End Class