After doing Me.windwstate=formwindowstate.maxmized then form becomes blank.

Me.Width = (Screen.PrimaryScreen.Bounds.Width)
Me.Height = (Screen.PrimaryScreen.Bounds.Height)
imgDelta.Image = System.Drawing.Image.FromFile("amit.jpg")
Me.Visible = True
Me.CreateGraphics.DrawImage(imgDelta.Image, 0, 0, Me.Width, Me.Height)
Me.WindowState = FormWindowState.Maximized


after performing Me.windowstate step in vb.net, form become blank and no jpeg mage is showing in form, and also when control goes from form_load method all draw image part gets blank.

before Me.windowstate step ,form is painted with jpeg image.


Kindly help me toresolve this issue.

You drew on the form, then maximized it, causing it to refresh itself. This cause the Paint event to fire off which then erased the image you just drew.
1) Set the Maximize first, then draw the image
2) Draw the image in the Paint event and use the Graphics object that's passed into the event (in other words, don't go creating a new one)

-tg

Quote:

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Originally Posted by techgnome

You drew on the form, then maximized it, causing it to refresh itself. This cause the Paint event to fire off which then erased the image you just drew.
1) Set the Maximize first, then draw the image
2) Draw the image in the Paint event and use the Graphics object that's passed into the event (in other words, don't go creating a new one)

-tg

---

If we draw in paint event then t gets fire automatically in any time. This cause problem for me

can i do like this ,

Private Sub form1_Paint(ByVal sender As Object, ByVal e As System.Windows.Forms.PaintEventArgs) Handles MyBase.Paint
If imgDelta.Image Is Nothing Then
Me.CreateGraphics.DrawImage(imgDelta.Image, 0, 0, Me.Width, Me.Height)
End If


Tats what you r saying ?

or i need to modify something kindly suggest me.

Hi techgnoe,

and form become blank also when form_load method ends. What i need to do to retain "form image" which is drawn by draw image .

Change Me.CreateGraphics to e.Graphics

Quote:

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Originally Posted by AmitMckvie

If we draw in paint event then t gets fire automatically in any time. This cause problem for me

---

What problem(s) does it cause?

Using CreateGraphics() is always wrong.

If you draw outside the Paint event, everything you do will be erased when the next Paint event happens. So using CreateGraphics() means you're responsible for redrawing after every Paint event, which means you may as well draw in the Paint event.

Quote:

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If we draw in paint event then t gets fire automatically in any time. This cause problem for me

---

This doesn't make any sense to me. What kind of problem? I bet it's easier to solve that problem then the one in the original question.

(haha me and si_the_geek had the same thought!)

what is it exactly you're trying to accomplish here? Why take the image of a picture box and draw it onto the form? are you trying to use it as the form's background?

And yes, if you draw it in the paint event, it gets called automaticvally anytime something on the form changes. In many cases, when drawing on the form directly, that's what you want. Otherwise, if you drag another window over, it you'll lose any drawing on the form where the other form passed over it... that's why the paint event exists, so you can re-paint what ever you need.

And what I had in mind was more along the lines of:

Code:

---

Private Sub form1_Paint(ByVal sender As Object, ByVal e As System.Windows.Forms.PaintEventArgs) Handles MyBase.Paint
    Me.CreateGraphics.DrawImage(imgDelta.Image, 0, 0, Me.Width, Me.Height)
End Sub

---

But yeah, depending on your needs, something like that.

-tg

Quote:

---

Originally Posted by techgnome

[...]

And what I had in mind was more along the lines of:

Code:

---

Private Sub form1_Paint(ByVal sender As Object, ByVal e As System.Windows.Forms.PaintEventArgs) Handles MyBase.Paint
    Me.CreateGraphics.DrawImage(imgDelta.Image, 0, 0, Me.Width, Me.Height)
End Sub

---

But yeah, depending on your needs, something like that.

-tg

---

You should switch that to e.Graphics. There's no reason to call CreateGraphics() there, and it creates a Graphics object you don't dispose so it could end up chewing through a lot of memory until the GC runs.

I understood what you guys are suggesting me but, i am migrating vb 6.0 to vb.net . in vb 6.0 through paint picture they are painting a form and there are no paint event as well but same thing i wan to do in vb.net through draw image , it want paint event, in paintpicture after window maximize also forms retaining pictures. Thats why i confuse.

Quote:

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Originally Posted by Sitten Spynne

Using CreateGraphics() is always wrong.

---

huh? what?
ok, it is not the best choice here, but please: no rigid rules that Claim to be true in every circumstand.

In paint event i can not write paint method , my project something first i draw big 1 image with company logo under form_load method then through timer.tick method we draw 2,3,4... on top of 1 image.but once control reach in timer.tick event 1 gets dis appear but 2,3,4... is painted as normal.

In VB6 forms automatically have a secondary image, and that is what you draw/write to. In the paint event, it copies that image to the form.

You can do the same in VB.Net if you want, but you need to create the secondary image yourself.

Quote:

---

Originally Posted by AmitMckvie

In paint event i can not write paint method , my project something first i draw big 1 image with company logo under form_load method then through timer.tick method we draw 2,3,4... on top of 1 image.but once control reach in timer.tick event 1 gets dis appear but 2,3,4... is painted as normal.

---

It would have been better if you had shown the timer code, but in simple terms you should move the painting code from the timer to the paint event (use variables to determine what to paint if you need to), or you could use the secondary image approach.

It sounds like you're sort of trying to make a constantly animated background? Or do you just want it to animate the one time? Either way is doable, it just takes a little thought.

If you have 4 images you're stacking on top of each other, you can represent the "state" of that with an Integer. 0 = just the background. 1 = background + image1, and so on. Each timer tick should change the state and Invalidate the Form. The Paint event should check the state and draw only the images the state indicates. To accomplish either effect:

• For constant animation, the timer should change the state from 3 to 0 at the end.
• For a one-time animation, the timer should stop at the end, and you could consider caching the image.

Here's a quick demo of both behaviors:

Code:

---

Public Class Form1

    Private _animationTimer As Timer

    Private _loopAnimationState As Integer
    Private _constantAnimationState As Integer

    Private _images(3) As Image

    Public Sub New()
        Me.DoubleBuffered = True
        InitializeComponent()
        InitializeImages()
    End Sub

    Protected Overrides Sub OnShown(e As EventArgs)
        MyBase.OnShown(e)

        _animationTimer = New Timer()
        _animationTimer.Interval = 3000
        AddHandler _animationTimer.Tick, AddressOf WhenAnimationTimerTicks

        StartAnimations()
    End Sub

    Private Sub InitializeImages()
        _images(0) = CreateImage(Color.Red, 100)
        _images(1) = CreateImage(Color.Green, 75)
        _images(2) = CreateImage(Color.Yellow, 50)
        _images(3) = CreateImage(Color.Black, 25)
    End Sub

    Private Function CreateImage(ByVal color As Color, ByVal squareSize As Integer) As Image
        Dim bmp As New Bitmap(squareSize, squareSize)
        Using g As Graphics = Graphics.FromImage(bmp)
            g.Clear(color)
        End Using

        Return bmp
    End Function

    Private Sub StartAnimations()
        _loopAnimationState = 0
        _constantAnimationState = 0

        _animationTimer.Start()
    End Sub

    Protected Overrides Sub OnPaint(e As PaintEventArgs)
        MyBase.OnPaint(e)

        ' Make sure we don't try to draw before the images are initialized.
        If _images(0) IsNot Nothing Then
            DrawAnimatedRegion(e.Graphics, _loopAnimationState, New Point(25, 25))
            DrawAnimatedRegion(e.Graphics, _constantAnimationState, New Point(225, 25))
        End If
    End Sub

    Private Sub DrawAnimatedRegion(ByVal g As Graphics, ByVal state As Integer, ByVal baseLocation As Point)

        For stateIndex As Integer = 0 To state
            Dim stateImage As Image = _images(stateIndex)
            Dim imageLocation As New Point(baseLocation.X + (12 * stateIndex), baseLocation.Y + 12 * stateIndex)
            g.DrawImage(stateImage, imageLocation)
        Next
    End Sub

    Private Sub WhenAnimationTimerTicks(ByVal sender As Object, ByVal e As EventArgs)
        If _constantAnimationState < 3 Then
            _constantAnimationState += 1
        End If

        If _loopAnimationState <> 3 Then
            _loopAnimationState += 1
        Else
            _loopAnimationState = 0
        End If

        Invalidate()
    End Sub

End Class

---

Quote:

---

Quote:

---

Originally Posted by digitalShaman

huh? what?
ok, it is not the best choice here, but please: no rigid rules that Claim to be true in every circumstand.

---

---

I wrote WinForms controls professionally for 6 years, and I've been answering questions about it for 14 years. I have yet to find a situation where I needed to call CreateGraphics(). It always creates more work because you have to coordinate with what goes on in the Paint event, and the easiest way to coordinate with the Paint event is "just handle the Paint event".

Well, technically if you wanted to simulate the persistent AutoRedraw buffer of a VB6 application in .Net, you can create your own bitmap as si_the_geek mentioned and assign it to the BackGroundImage of your form.
You would then draw into that bitmap and call the form's invalidate method so that it repaints itself from that background image, i.e. the background image of the form is a reference to the same object that you created so you can draw into it using your reference and the form will refresh itself from its reference to the same object.

In that case you don't have to have any code in the paint event since the form will automatically refresh itself from the background image when needed or directed.

I modified your code from post #1 below. I'm not sure if you really need imgDelta, but assuming it is a picturebox, I left that line of code in and used it as is.

I added a button to show that you can update the bitmap using your reference and see the update when the form redraws itself.

Code:

---

Public Class Form1
  Dim myBackGroundImage As New Bitmap(Screen.PrimaryScreen.Bounds.Width, Screen.PrimaryScreen.Bounds.Height)
  Dim rand As New Random

  Private Sub Form1_Load(sender As System.Object, e As System.EventArgs) Handles MyBase.Load
    Me.Width = (Screen.PrimaryScreen.Bounds.Width)
    Me.Height = (Screen.PrimaryScreen.Bounds.Height)
    imgDelta.Image = System.Drawing.Image.FromFile("c:\c\tst.jpg")
    Using g As Graphics = Graphics.FromImage(myBackGroundImage)
      g.DrawImage(imgDelta.Image, 0, 0, Me.Width, Me.Height)
    End Using
    Me.WindowState = FormWindowState.Maximized
    Me.BackgroundImage = myBackGroundImage
    DoubleBuffered = True
  End Sub

  Private Sub Button1_Click(sender As System.Object, e As System.EventArgs) Handles Button1.Click
    Using g As Graphics = Graphics.FromImage(myBackGroundImage)

      g.FillEllipse(Brushes.Red, rand.Next(1000), rand.Next(1000), 20 + rand.Next(100), 20 + rand.Next(100))
    End Using
    Invalidate()  'so the form redraws itself and you see your updated bitmap.
  End Sub
End Class

---

Hi Passel,

I am migrating code from vb 6.0 to vb.net .

I have one doubt that i need to draw one image in form_load() method and after ending form_load method control is going to timer_tick event and there we paint 2,3,4,5...6 on top of 1(main image which is drawn in form_load() method).

in vb 6.0 they use form.paintpitcure( imgdelta.image,0,0,,me.width,me.height) in form_load method and after drawing it ,control goes to timer_tick method but painted part is not disappeared.

But same thing i did through me.creategraphics.drawimage(imgdelta.image,0,0,me.width,me.height) in form_load method and as soon as control coming out from form_load method painted part gets disappered in timer_tick event .

kindly suggest me.

Well it depends on what you're doing in the timer event to paint the numbers on top.
And of course there are many ways to accomplish the same appearance.
If the numbers should appear on the background image, but then be erased and replaced by another number then you wouldn't want to draw the number to the bitmap, but draw the number in the paint event along the lines suggested by Sitten Spynne.

When you call the Invalidate method, the form will refresh the background automatically from the background image assigned, thus clearing anything that was drawn in a previous paint event. Therefore, you wouldn't have to specifically erase the number because it would disappear automatically since it is not part of the background image. Then you can draw anything you want "on top" of that background image in the Paint event.

I modified my previous example. You can still click on the button to draw a red ellipse to the bitmap at any time and it becomes a permanent part of the bitmap. But now a timer is added that will increment a number, and call the invalidate method.
The invalidation will cause a paint event and in the paint event the number is printed at a location of the form. Whatever is drawn in the paint event is essentially dynamic. If you want to "erase" the number permanently, you just have a flag that skips drawing the number in the paint event, and trigger the paint event to "erase" it, i.e. you won't draw it so it won't be there.

Code:

---

Public Class Form1
  Dim myBackGroundImage As New Bitmap(Screen.PrimaryScreen.Bounds.Width, Screen.PrimaryScreen.Bounds.Height)
  Dim rand As New Random
  Dim frmCount As Long

  Private Sub Form1_Load(sender As System.Object, e As System.EventArgs) Handles MyBase.Load
    Me.Width = (Screen.PrimaryScreen.Bounds.Width)
    Me.Height = (Screen.PrimaryScreen.Bounds.Height)
    imgDelta.Image = System.Drawing.Image.FromFile("c:\c\tst.jpg")
    Using g As Graphics = Graphics.FromImage(myBackGroundImage)
      g.DrawImage(imgDelta.Image, 0, 0, Me.Width, Me.Height)
    End Using
    Me.WindowState = FormWindowState.Maximized
    Me.BackgroundImage = myBackGroundImage
    DoubleBuffered = True
    Timer1.Interval = 500
    Timer1.Start()
  End Sub

  Private Sub Button1_Click(sender As System.Object, e As System.EventArgs) Handles Button1.Click
    Using g As Graphics = Graphics.FromImage(myBackGroundImage)

      g.FillEllipse(Brushes.Red, rand.Next(1000), rand.Next(1000), 20 + rand.Next(100), 20 + rand.Next(100))
    End Using
    Invalidate()
  End Sub

  Private Sub Timer1_Tick(sender As System.Object, e As System.EventArgs) Handles Timer1.Tick
    frmCount += 1
    Invalidate()
  End Sub

  Private Sub Form1_Paint(sender As Object, e As System.Windows.Forms.PaintEventArgs) Handles Me.Paint
    Using f As Font = New Font("Courier", 96, FontStyle.Bold)
      e.Graphics.DrawString(frmCount.ToString, f, Brushes.Blue, 400, 400)

    End Using
  End Sub
End Class

---

There are many other ways end up with the same visual effect, i.e. doing all the drawing in the paint event, both background and numbers, and many ways to accomplish that as well, like using multiple bitmaps to draw into, and then draw them collectively in the paint event. This only scratches the surface of options available.

Quote:

---

Originally Posted by Sitten Spynne

I wrote WinForms controls professionally for 6 years, and I've been answering questions about it for 14 years. I have yet to find a situation where I needed to call CreateGraphics(). It always creates more work because you have to coordinate with what goes on in the Paint event, and the easiest way to coordinate with the Paint event is "just handle the Paint event".

---

sure if you stay just with control drawing. but how do you draw into a newly created bitmap without using .CreateGraphics()? so that the bitmap can be saved later on or drawn in paint event or whatever.

Quote:

---

Originally Posted by digitalShaman

sure if you stay just with control drawing. but how do you draw into a newly created bitmap without using .CreateGraphics()? so that the bitmap can be saved later on or drawn in paint event or whatever.

---

I did it in the example above. You create the Bitmap you want, then use Graphics.FromImage().

Control.CreateGraphics() is a method of Control. You can't use it to draw on a bitmap. It's used to obtain a Graphics object capable of drawing on a Control. That drawing will be erased on the next invalidation cycle, so you also have to go make sure you redraw whatever it is in the Paint event. So it turns out it's all-around easier to handle the Paint event and call Invalidate() to raise Paint instead of having your drawing code duplicated in two places. It's also a little more complex because you become responsible for calling Dispose() on that Graphics object at the appropriate time.

Bitmaps/images don't have an invalidation cycle like controls, so the only way to draw to them is to call Graphics.FromImage(), their equivalent to Control.CreateGraphics(). Because there's no other way, you're correct to state this is the "right" way.

But when I said "CreateGraphics()", I specifically meant Control.CreateGraphics(), not "...and the analog for any other type of graphical object".

i do apologize! i mixed up .CreateGraphics and Graphics.FromImage(). I had a bmp.CreateGraphics method in mind that in fact does not exist :P

i'm just allergic against rigid rules but thats prop. my wicked personality ;)