Problem with mouse events on form with PictureBox

[dfemery]

I am writing a program to draw lines over an existing image within a PictureBox. The routine works perfectly INSIDE the PictureBox (I'm drawing a rubberband line), but I cannot get the mouse to work on any buttons OUTSIDE the picturebox. (In this example, Button1 doesn't respond)

I have written three mouse event subs (MouseUP, MouseMOVE, MouseDOWN) that work within the PictureBox, but I don't know how to write the program so that I get normal mouse function when the mouse is pointing outside the PictureBox.

This MUST me easy to do... but I'm obviously missing something. I'd really appreciate some help with this.

Here is (most of) my code , some of it borrowed from various examples I've found here and there. I'm using Visual Studio 2005. (the form contains PictureBox1, TextBox1, TextBox2, TextBox3, TextBox4, Button1)

Imports System.Drawing
Imports System.Drawing.Imaging
Imports System.Windows.Forms 
Public Class Form1
    Public bitmap As System.Drawing.Bitmap
    Public bm As System.Drawing.Bitmap
    Public BitmapOrg As System.Drawing.Bitmap
    Private drag As Boolean = False
    Private DrawMode As Integer = 1
    Private x0, y0, x, y As Integer
    Private cx, cy As Integer
    Private gB As Graphics 
 
    Private Sub Form1_load(ByVal sender As System.Object, ByVal e As System.EventArgs) Handles MyBase.Load 
    End Sub 
 
    Private Sub PictureBox1_MouseDown(ByVal sender As Object, ByVal e As System.Windows.Forms.MouseEventArgs) Handles PictureBox1.MouseDown
        Dim p As Point = New Point(e.X, e.Y)
        x0 = p.X    
        y0 = p.Y   
        TextBox1.Text = "MouseDOWN " & CStr(x0) & ", " & CStr(y0)
        drag = True
    End Sub 
    Private Sub PictureBox1_MouseMove(ByVal sender As Object, ByVal e As System.Windows.Forms.MouseEventArgs) Handles PictureBox1.MouseMove
        Dim p As Point = New Point(e.X, e.Y)
        x = p.X
        y = p.Y
        cx = x - x0
        cy = y - y0
        TextBox2.Text = "MouseMOVE " & CStr(cy) & ", " & CStr(cx)
        If drag Then
            Invalidate()
        End If
    End Sub 
    Private Sub PictureBox1_MouseUp(ByVal sender As Object, ByVal e As System.Windows.Forms.MouseEventArgs) Handles PictureBox1.MouseUp
        cx = x - x0
        cy = y - y0
        TextBox3.Text = "MouseUP " & CStr(cy) & ", " & CStr(cx)
        Dim pen As Pen = New Pen(Color.Yellow)
        RefreshBackground()
        drag = False
        pen.Dispose()
    End Sub 
    Private Sub Form1_Paint(ByVal sender As Object, ByVal e As System.Windows.Forms.PaintEventArgs) Handles MyBase.Paint
        bitmap = New System.Drawing.Bitmap("c:\Bitmaps\Test_A.bmp")
        Me.PictureBox1.Image = bitmap
        Dim g As Graphics = Graphics.FromImage(bitmap)
        Dim pen As Pen = New Pen(Color.Yellow)
        TextBox4.Text = CStr(drag.ToString)
        If drag Then
            g.DrawLine(pen, x0, y0, x, y)
        End If
        pen.Dispose()
    End Sub 
    Private Sub button1_Click(ByVal sender As Object, ByVal e As System.EventArgs)
        MsgBox("Here at Button 1")
    End Sub 
    Private Sub Form1_SizeChanged(ByVal sender As Object, ByVal e As System.EventArgs) Handles PictureBox1.SizeChanged
        RefreshBackground()
    End Sub 
    Private Sub RefreshBackground()
        Dim sz As Size = Me.Size
        Dim rt As Rectangle = New Rectangle(0, 0, sz.Width, sz.Height)
        Dim bm As Bitmap
        If (bm IsNot Nothing) Then
            bm = bitmap.Clone(rt, bitmap.PixelFormat)
            BackgroundImage = bm
        End If
    End Sub 
    Public Sub PictureBox1_Click(ByVal sender As System.Object, ByVal e As System.EventArgs) Handles PictureBox1.Click
 
    End Sub
 
End Class

[tlhintoq]

TIP: When you are writing your question, there is a button on the tool bar that wraps the [code] tags around your copy/pasted code. It helps a bunch. Its the button with a '#' on it. More on tags. They're cool. Check'em out.

[tlhintoq]

Private Sub Form1_Paint(ByVal sender As Object, ByVal e As System.Windows.Forms.PaintEventArgs) Handles MyBase.Paint
        bitmap = New System.Drawing.Bitmap("c:\Bitmaps\Test_A.bmp")

Every time you paint you are reading the base image from the harddrive? Ouch!
May I suggest you read it one time at startup and use it (or a clone of it) through out the rest of the application. This is not only going to slow you down a LOT but beat the heck out of your drive.

Private Sub RefreshBackground()
        Dim sz As Size = Me.Size
        Dim rt As Rectangle = New Rectangle(0, 0, sz.Width, sz.Height)
        Dim bm As Bitmap
        If (bm IsNot Nothing) Then
            bm = bitmap.Clone(rt, bitmap.PixelFormat)
            BackgroundImage = bm
        End If
    End Sub 

Once you reassign a new BackgroundImage that is going to trigger a new Form1_Paint event, and reload the file from harddrive.

I kinda wonder if the system isn't just overwhelmed.

You might also want to toss in an Application.DoEvents() at the end of your Form1_Paint so you can give some CPU time to other things, like other button clicks.

[dfemery]

You are absolutely correct about the repeated disk reads... I jfollowed your advice and cloned the bitmap... it was something I should have caught but I was entirely focused on the mouse issue!

Anyway, that was not the problem.

The problem was a foolish error... and simple as I thought it might be! The Button1 sub that wasn't working needed a "Handles" reference!!!

It now works fine by adding "Handles Button1.Click" so that the sub now reads:

Private Sub button1_Click(ByVal sender As Object, ByVal e As_ System.EventArgs) Handles Button1.Click
MsgBox("Here at Button 1")
End Sub

Anyway... many thanks for the assistance!

--Dave Emery