How to update graphics at a form

[PL_Andrev]

Hello,

I'm trying to understand how to events work (I'm NET beginner), so my code looks like:

Public Class Form1
    Public x As Single()
    Public y As Single()
    Private Sub Form1_Load(ByVal sender As System.Object, ByVal e As System.EventArgs) Handles MyBase.Load
        x = New Single(1) {100, 200}
        y = New Single(1) {100, 100}
    End Sub
    Public Sub Form1_Paint(ByVal sender As Object, ByVal e As System.Windows.Forms.PaintEventArgs) Handles Me.Paint
        e.Graphics.DrawLine(Pens.Beige, x(0), y(0), x(1), y(1))
        Label1.Text = "Line is OK"
    End Sub
    Private Sub Form1_MouseClick(ByVal sender As System.Object, ByVal e As System.Windows.Forms.MouseEventArgs) Handles MyBase.MouseClick
        MsgBox("Mouse clicked")
        y(0) = 200 : y(1) = 200
        Me.Label1.Text = "Line is moved"
    End Sub
End Class

Unfortunately when mouse is clicked on form, the msgbox is shown only, but Line is not moved and Label is not changed...
What's wrong with this code?

[stanav]

In mouse.click event handler, after you set the values for x and y, you call the the form's Refresh method to repaint the whole form or for better performance, you use the form.Invalidate method and specify the region you want to repaint in the arguments.