VB.Net/GUI/Form OnPaint

Get Other Form Paint event

Imports System
Imports System.Drawing
Imports System.Windows.Forms
public class MainClass
   Shared Sub Main()
      Dim form1 As Form = New Form1
      Application.Run(form1)
   End Sub
End Class

Public Class Form1
    Inherits System.Windows.Forms.Form
#Region " Windows Form Designer generated code "
    Public Sub New()
        MyBase.New()
        "This call is required by the Windows Form Designer.
        InitializeComponent()
        "Add any initialization after the InitializeComponent() call
    End Sub
    "Form overrides dispose to clean up the component list.
    Protected Overloads Overrides Sub Dispose(ByVal disposing As Boolean)
        If disposing Then
            If Not (components Is Nothing) Then
                components.Dispose()
            End If
        End If
        MyBase.Dispose(disposing)
    End Sub
    Friend WithEvents cmdDrawStuff As System.Windows.Forms.Button
    Friend WithEvents cmdInvalidate As System.Windows.Forms.Button
    Friend WithEvents cmdOtherForm As System.Windows.Forms.Button
    "Required by the Windows Form Designer
    Private components As System.ruponentModel.IContainer
    "NOTE: The following procedure is required by the Windows Form Designer
    "It can be modified using the Windows Form Designer.  
    "Do not modify it using the code editor.
    <System.Diagnostics.DebuggerStepThrough()> Private Sub InitializeComponent()
        Me.cmdOtherForm = New System.Windows.Forms.Button()
        Me.cmdDrawStuff = New System.Windows.Forms.Button()
        Me.cmdInvalidate = New System.Windows.Forms.Button()
        Me.SuspendLayout()
        "
        "cmdOtherForm
        "
        Me.cmdOtherForm.Location = New System.Drawing.Point(184, 136)
        Me.cmdOtherForm.Name = "cmdOtherForm"
        Me.cmdOtherForm.Size = New System.Drawing.Size(96, 32)
        Me.cmdOtherForm.TabIndex = 2
        Me.cmdOtherForm.Text = "Other Form"
        "
        "cmdDrawStuff
        "
        Me.cmdDrawStuff.Location = New System.Drawing.Point(184, 80)
        Me.cmdDrawStuff.Name = "cmdDrawStuff"
        Me.cmdDrawStuff.Size = New System.Drawing.Size(96, 32)
        Me.cmdDrawStuff.TabIndex = 1
        Me.cmdDrawStuff.Text = "Draw Stuff"
        "
        "cmdInvalidate
        "
        Me.cmdInvalidate.Location = New System.Drawing.Point(184, 24)
        Me.cmdInvalidate.Name = "cmdInvalidate"
        Me.cmdInvalidate.Size = New System.Drawing.Size(96, 32)
        Me.cmdInvalidate.TabIndex = 0
        Me.cmdInvalidate.Text = "Invalidate"
        "
        "Form1
        "
        Me.AutoScaleBaseSize = New System.Drawing.Size(5, 13)
        Me.ClientSize = New System.Drawing.Size(292, 273)
        Me.Controls.AddRange(New System.Windows.Forms.Control() {Me.cmdOtherForm, Me.cmdDrawStuff, Me.cmdInvalidate})
        Me.Name = "Form1"
        Me.Text = "Form1"
        Me.ResumeLayout(False)
    End Sub
#End Region
    Private Sub OtherFormPaint(ByVal sender As Object, ByVal args As PaintEventArgs)
            Console.WriteLine("Other paint arrived")
    End Sub
    Private Sub cmdOtherForm_Click(ByVal sender As System.Object, ByVal e As System.EventArgs) Handles cmdOtherForm.Click
        Dim f As New Form1()
        f.Visible = True
        AddHandler f.Paint, AddressOf Me.OtherFormPaint
    End Sub
End Class

Override Form OnPaint and OnResize Method

Imports System
Imports System.Drawing
Imports System.Windows.Forms
public class MainClass
   Shared Sub Main()
      Dim form1 As Form = New Form1
      Application.Run(form1)
   End Sub
End Class

Public Class Form1
    Inherits System.Windows.Forms.Form
#Region " Windows Form Designer generated code "
    Public Sub New()
        MyBase.New()
        "This call is required by the Windows Form Designer.
        InitializeComponent()
        "Add any initialization after the InitializeComponent() call
    End Sub
    "Form overrides dispose to clean up the component list.
    Protected Overloads Overrides Sub Dispose(ByVal disposing As Boolean)
        If disposing Then
            If Not (components Is Nothing) Then
                components.Dispose()
            End If
        End If
        MyBase.Dispose(disposing)
    End Sub
    Friend WithEvents cmdDrawStuff As System.Windows.Forms.Button
    Friend WithEvents cmdInvalidate As System.Windows.Forms.Button
    Friend WithEvents cmdOtherForm As System.Windows.Forms.Button
    "Required by the Windows Form Designer
    Private components As System.ruponentModel.IContainer
    "NOTE: The following procedure is required by the Windows Form Designer
    "It can be modified using the Windows Form Designer.  
    "Do not modify it using the code editor.
    <System.Diagnostics.DebuggerStepThrough()> Private Sub InitializeComponent()
        Me.cmdOtherForm = New System.Windows.Forms.Button()
        Me.cmdDrawStuff = New System.Windows.Forms.Button()
        Me.cmdInvalidate = New System.Windows.Forms.Button()
        Me.SuspendLayout()
        "
        "cmdOtherForm
        "
        Me.cmdOtherForm.Location = New System.Drawing.Point(184, 136)
        Me.cmdOtherForm.Name = "cmdOtherForm"
        Me.cmdOtherForm.Size = New System.Drawing.Size(96, 32)
        Me.cmdOtherForm.TabIndex = 2
        Me.cmdOtherForm.Text = "Other Form"
        "
        "cmdDrawStuff
        "
        Me.cmdDrawStuff.Location = New System.Drawing.Point(184, 80)
        Me.cmdDrawStuff.Name = "cmdDrawStuff"
        Me.cmdDrawStuff.Size = New System.Drawing.Size(96, 32)
        Me.cmdDrawStuff.TabIndex = 1
        Me.cmdDrawStuff.Text = "Draw Stuff"
        "
        "cmdInvalidate
        "
        Me.cmdInvalidate.Location = New System.Drawing.Point(184, 24)
        Me.cmdInvalidate.Name = "cmdInvalidate"
        Me.cmdInvalidate.Size = New System.Drawing.Size(96, 32)
        Me.cmdInvalidate.TabIndex = 0
        Me.cmdInvalidate.Text = "Invalidate"
        "
        "Form1
        "
        Me.AutoScaleBaseSize = New System.Drawing.Size(5, 13)
        Me.ClientSize = New System.Drawing.Size(292, 273)
        Me.Controls.AddRange(New System.Windows.Forms.Control() {Me.cmdOtherForm, Me.cmdDrawStuff, Me.cmdInvalidate})
        Me.Name = "Form1"
        Me.Text = "Form1"
        Me.ResumeLayout(False)
    End Sub
#End Region
    Dim backgroundbitmap As Bitmap
    Protected Overrides Sub OnResize(ByVal e As System.EventArgs)
        If Not Me.ClientRectangle.IsEmpty Then            
            If Not Me.ClientSize.Equals(New Size(backgroundbitmap.Width, backgroundbitmap.Height)) Then
                Dim newbitmap As Bitmap
                newbitmap = New Bitmap(Me.ClientSize.Width, Me.ClientSize.Height)
                If Not backgroundbitmap Is Nothing Then
                    Dim g As Graphics = graphics.FromImage(newbitmap)
                    g.DrawImage(backgroundbitmap, 0, 0)
                End If
                backgroundbitmap = newbitmap
            End If
        End If
    End Sub
    Protected Overrides Sub OnPaint(ByVal e As System.Windows.Forms.PaintEventArgs)
"        MyBase.OnPaint(e)
        e.Graphics.DrawLine(pens.Black, 0, 0, 200, 200)
        e.Graphics.DrawLine(pens.Red, 0, 200, 200, 0)
        "RaiseEvent Paint(Me, e)
    End Sub
End Class

Paint Bitmap on a form using the Paint Method

Imports System
Imports System.Collections
Imports System.Data
Imports System.IO
Imports System.Xml.Serialization
Imports System.Windows.Forms
Imports System.Drawing
Imports System.Drawing.Drawing2D
Imports System.Drawing.Text
Imports System.Drawing.Printing

Public Class MainClass
    Shared Sub Main()
       Dim form1 As Form = New Form1()
       Application.Run(form1) 
    End Sub
End Class


Public Class Form1
    Inherits System.Windows.Forms.Form
#Region " Windows Form Designer generated code "
    Public Sub New()
        MyBase.New()
        "This call is required by the Windows Form Designer.
        InitializeComponent()
        "Add any initialization after the InitializeComponent() call
    End Sub
    "Form overrides dispose to clean up the component list.
    Protected Overloads Overrides Sub Dispose(ByVal disposing As Boolean)
        If disposing Then
            If Not (components Is Nothing) Then
                components.Dispose()
            End If
        End If
        MyBase.Dispose(disposing)
    End Sub
    "Required by the Windows Form Designer
    Private components As System.ruponentModel.Container
    "NOTE: The following procedure is required by the Windows Form Designer
    "It can be modified using the Windows Form Designer.  
    "Do not modify it using the code editor.
    <System.Diagnostics.DebuggerStepThrough()> Private Sub InitializeComponent()
        "
        "Form1
        "
        Me.AutoScaleBaseSize = New System.Drawing.Size(6, 15)
        Me.ClientSize = New System.Drawing.Size(336, 268)
        Me.Name = "Form1"
        Me.Text = "The simplest drawing program"
    End Sub
#End Region
    Private Sub Form1_Load(ByVal sender As System.Object, ByVal e As System.EventArgs) Handles MyBase.Load
    End Sub
    Protected Overrides Sub OnPaint(ByVal e As PaintEventArgs)
        MyBase.OnPaint(e)
        Dim g As Graphics
        g = e.Graphics()
        g.DrawImage(New Bitmap("figure2.bmp"), 0, 0)
    End Sub
End Class

To call MyBase.OnPaint(e) or not to call

Imports System
Imports System.Drawing
Imports System.Windows.Forms
public class MainClass
   Shared Sub Main()
      Dim form1 As Form = New Form1
      Application.Run(form1)
   End Sub
End Class

Public Class Form1
    Inherits System.Windows.Forms.Form
#Region " Windows Form Designer generated code "
    Public Sub New()
        MyBase.New()
        "This call is required by the Windows Form Designer.
        InitializeComponent()
        "Add any initialization after the InitializeComponent() call
    End Sub
    "Form overrides dispose to clean up the component list.
    Protected Overloads Overrides Sub Dispose(ByVal disposing As Boolean)
        If disposing Then
            If Not (components Is Nothing) Then
                components.Dispose()
            End If
        End If
        MyBase.Dispose(disposing)
    End Sub
    Friend WithEvents cmdDrawStuff As System.Windows.Forms.Button
    Friend WithEvents cmdInvalidate As System.Windows.Forms.Button
    Friend WithEvents cmdOtherForm As System.Windows.Forms.Button
    "Required by the Windows Form Designer
    Private components As System.ruponentModel.IContainer
    "NOTE: The following procedure is required by the Windows Form Designer
    "It can be modified using the Windows Form Designer.  
    "Do not modify it using the code editor.
    <System.Diagnostics.DebuggerStepThrough()> Private Sub InitializeComponent()
        Me.cmdOtherForm = New System.Windows.Forms.Button()
        Me.cmdDrawStuff = New System.Windows.Forms.Button()
        Me.cmdInvalidate = New System.Windows.Forms.Button()
        Me.SuspendLayout()
        "
        "cmdOtherForm
        "
        Me.cmdOtherForm.Location = New System.Drawing.Point(184, 136)
        Me.cmdOtherForm.Name = "cmdOtherForm"
        Me.cmdOtherForm.Size = New System.Drawing.Size(96, 32)
        Me.cmdOtherForm.TabIndex = 2
        Me.cmdOtherForm.Text = "Other Form"
        "
        "cmdDrawStuff
        "
        Me.cmdDrawStuff.Location = New System.Drawing.Point(184, 80)
        Me.cmdDrawStuff.Name = "cmdDrawStuff"
        Me.cmdDrawStuff.Size = New System.Drawing.Size(96, 32)
        Me.cmdDrawStuff.TabIndex = 1
        Me.cmdDrawStuff.Text = "Draw Stuff"
        "
        "cmdInvalidate
        "
        Me.cmdInvalidate.Location = New System.Drawing.Point(184, 24)
        Me.cmdInvalidate.Name = "cmdInvalidate"
        Me.cmdInvalidate.Size = New System.Drawing.Size(96, 32)
        Me.cmdInvalidate.TabIndex = 0
        Me.cmdInvalidate.Text = "Invalidate"
        "
        "Form1
        "
        Me.AutoScaleBaseSize = New System.Drawing.Size(5, 13)
        Me.ClientSize = New System.Drawing.Size(292, 273)
        Me.Controls.AddRange(New System.Windows.Forms.Control() {Me.cmdOtherForm, Me.cmdDrawStuff, Me.cmdInvalidate})
        Me.Name = "Form1"
        Me.Text = "Form1"
        Me.ResumeLayout(False)
    End Sub
#End Region
    Dim backgroundbitmap As Bitmap
    Protected Overrides Sub OnResize(ByVal e As System.EventArgs)
        If Not Me.ClientRectangle.IsEmpty Then            
            If Not Me.ClientSize.Equals(New Size(backgroundbitmap.Width, backgroundbitmap.Height)) Then
                Dim newbitmap As Bitmap
                newbitmap = New Bitmap(Me.ClientSize.Width, Me.ClientSize.Height)
                If Not backgroundbitmap Is Nothing Then
                    Dim g As Graphics = graphics.FromImage(newbitmap)
                    g.DrawImage(backgroundbitmap, 0, 0)
                End If
                backgroundbitmap = newbitmap
            End If
        End If
    End Sub
    Protected Overrides Sub OnPaint(ByVal e As System.Windows.Forms.PaintEventArgs)
"        MyBase.OnPaint(e)
        e.Graphics.DrawLine(pens.Black, 0, 0, 200, 200)
        e.Graphics.DrawLine(pens.Red, 0, 200, 200, 0)
        "RaiseEvent Paint(Me, e)
    End Sub
End Class