Sizechanged event question...

[johnb41]

I have a Picturebox that has an image displayed inside. Through code,
I was able to have the "whole image" display in it without distortion.
(Like a "Fit All" in most any image viewer program)

Now, when the Picturebox gets resized by the user, I want the image to
recalculate and display as "Fit All" again.

So I have code in my SizeChanged event of the picturebox. When the
"size changed", it does it's calculation, and displays properly.

It works, but there is a problem: If the user drags the Picturebox
window larger or smaller, the SizeChanged event fires many times per
second. This causes alot of sluggishness in the app when trying to
display the image.

Is there anyway that i can have the SizeChanged event fire ONCE when
i'm done resizing the picturebox?

(By the way, the picturebox gets resized indirectly. It's dock is set
to Fill. When the interface "Next" to it gets resized, the Picturebox
naturally will resize accordingly)

Thanks for all your help!

John

[Cor Ligthert]

John,

You can use in the event two static variables (or one static point) to see
everytime if it changed,

I hope this helps,

Cor

[Peter Proost]

Hi John,

which sizechanged event are you handling? Because I have written a bit of
code which does the same thing, and tried it in these 3 events and they all
only fire once, when I finish dragging the form border

Private Sub ptbImg_Resize(B yVal sender As Object, ByVal e As
System.EventArg s) Handles ptbImg.Resize
End Sub

Private Sub ptbImg_SizeChan ged(ByVal sender As Object, ByVal e As
System.EventArg s) Handles _ ptbImg.SizeChan ged
End Sub

Private Sub frmResize_SizeC hanged(ByVal sender As Object, ByVal e As
System.EventArg s) Handles _ MyBase.SizeChan ged

End Sub

greetz Peter

--
Programming today is a race between software engineers striving to build
bigger and better idiot-proof programs, and the Universe trying to produce
bigger and better idiots. So far, the Universe is winning.

"Cor Ligthert" <no************ @planet.nl> schreef in bericht
news:uq******** ******@tk2msftn gp13.phx.gbl...

John,

You can use in the event two static variables (or one static point) to see
everytime if it changed,

I hope this helps,

Cor

[johnb41]

Peter,

It's actually a Panel that I have the SizeChanged event attached to.
This is so the I get scrollbars when the image is larger than the
Panel.

If it's not any trouble, could you post some sample code that makes the
event fire only once? I just did a sample test on resizing a plain
form:

Private Sub Form1_SizeChang ed(...) Handles MyBase.SizeChan ged
MessageBox.Show ("Size Changed!")
End Sub

The form won't even resize because the messagebox pops up immediately.
If I could get the messagebox to show up after finishing the resize,
that would be awesome. I could then adapt it to my real app.

Thanks!
John

[johnb41]

Thanks for the reply. You make it seem obvious! Could you describe
more of what you mean, as it's very unclear to me. Thanks!

John

[Peter Proost]

Hi John,

when you run you code:

Private Sub Form1_SizeChang ed(...) Handles MyBase.SizeChan ged
MessageBox.Show ("Size Changed!")
End Sub
the first time you see the messagebox pop up is because the form is
initialized, but after that the event normal only fires if you let go the
form border, so at the end of the SizeChanged event.

hth
Greetz Peter

--
Programming today is a race between software engineers striving to build
bigger and better idiot-proof programs, and the Universe trying to produce
bigger and better idiots. So far, the Universe is winning.

"johnb41" <or****@informa tik.com> schreef in bericht
news:11******** **************@ z14g2000cwz.goo glegroups.com.. . Peter,

It's actually a Panel that I have the SizeChanged event attached to.
This is so the I get scrollbars when the image is larger than the
Panel.

If it's not any trouble, could you post some sample code that makes the
event fire only once? I just did a sample test on resizing a plain
form:

Private Sub Form1_SizeChang ed(...) Handles MyBase.SizeChan ged
MessageBox.Show ("Size Changed!")
End Sub

The form won't even resize because the messagebox pops up immediately.
If I could get the messagebox to show up after finishing the resize,
that would be awesome. I could then adapt it to my real app.

Thanks!
John

[Cor Ligthert]

"johnb41"

Thanks for the reply. You make it seem obvious! Could you describe
more of what you mean, as it's very unclear to me. Thanks!

\\\
Static OldSize As Size
If Not OldSize.Equals( MeControl.Size) Then
....procedure
End If
///
I hope this helps,

Cor

[Herfried K. Wagner [MVP]]

"johnb41" <or****@informa tik.com> schrieb:

I have a Picturebox that has an image displayed inside. Through code,
I was able to have the "whole image" display in it without distortion.
(Like a "Fit All" in most any image viewer program)

Now, when the Picturebox gets resized by the user, I want the image to
recalculate and display as "Fit All" again.

So I have code in my SizeChanged event of the picturebox. When the
"size changed", it does it's calculation, and displays properly.

It works, but there is a problem: If the user drags the Picturebox
window larger or smaller, the SizeChanged event fires many times per
second. This causes alot of sluggishness in the app when trying to
display the image.

If you are experiencing a flicker, you could enable double buffering for the
picturebox control. To do so, create a class that inherits from
'System.Windows .Forms.PictureB ox' and provides the constructor shown in the
listing below:

\\\
Public Sub New()
Me.SetStyle( _
ControlStyles.R esizeRedraw Or _
ControlStyles.D oubleBuffer Or _
ControlStyles.A llPaintingInWmP aint, _
True _
)
Me.UpdateStyles ()
End Sub
///

Then you use your custom picturebox control instead of the standard Windows
Forms picturebox.

--
M S Herfried K. Wagner
M V P <URL:http://dotnet.mvps.org/>
V B <URL:http://classicvb.org/petition/>

[johnb41]

I gotta leave and do family stuff on this Memorial Day, so i'll only
post this quick message:

For me, the SizeChanged event seems to keep firing again and again,
until I let go of the mouse. This is in my real app, not the sample
one w/ the messagebox. For example, the image constantly tries to
redraw its self until I let go of the mouse.

I'll have to do more testing, and then play w/ Cor and herfried's
suggestions...

John

[johnb41]

Thanks for the code. But it made no difference. Here is what I now
have:

Private Sub Pnl_Image_SizeC hanged(...) Handles
Pnl_Image.SizeC hanged
Static OldSize As Size
If Not OldSize.Equals( Pnl_Image.Size) Then
' call procedure to resize and display image
End If
End Sub

What am I missing?

John