Visual Basic

Re: Issue with Image, PictureBox, AutoRedraw. Paint Brush Application In Vb 2005

6-Sep-07 8:06

Hi,

two comments:

1.
a PictureBox is not the right Control for this; its purpose is to show an existing Image,
no more, no less. Yours is not an Image, it is a painting that keeps evolving. So
I would suggest you take a simple Panel.

2.
The normal draw approach is to:
- have some data structures that represent the entire content of your drawing/painting;
- use keyboard/mouse events to modify these data structures;
- have the Paint handler "execute" the data structures, i.e. do the actual Graphics
operations.

As a result, you have:
- data structures ready for saving/restoring your structured document to /from file
- a visible result that gets redrawn automatically whenever it needs to (e.g. because
you resize the Form, uncover it, etc).
- the possibility to resize your drawing/painting based on its high-level representation
(such as font size), rather than pixel-based.

Now for real painting, the above may be rather difficult; if so, you could use a Bitmap,
create a Graphics for it once (with Graphics.FromImage; keep it in a class member),
and paint into that Graphics from your keyboard/mouse event handlers, then Invalidate()
your Panel. In the Panel's Paint handler simply DrawImage() the Bitmap.

But don't first paint on the screen, then try to capture the screen. That is inefficient
at best.

Smile | :)

Luc Pattyn [Forum Guidelines] [My Articles]

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nishkarsh_k8-Sep-07 9:38

nishkarsh_k

8-Sep-07 9:38

Hi Luc Pattyn
thanks for the info...

I will like to let my problem in more detail...

I have to use a tablet attached to the PC which acts as a input device for user

Was successfully able to do all what i told in my question in Vb6
Now when i migrated the code to Vb 2005 I was Not able to do it properly...

Issue is, the tablet sends packets as the user user writes on it... The tablet is of A4 size and the user can write on whole page
If i Use a data structure to store all points and then draw lines between them then one thing the data structure becomes too big and in low config system there is a threat of crashing or system becomes slow
other aspect is that a user will like to see what he writes in a similar size as what e is writing inso i need to make the picture box big which scrolls on the window...

As you suggested, if I use a panel then can i do all the above??

Re: Issue with Image, PictureBox, AutoRedraw. Paint Brush Application In Vb 2005

Luc Pattyn8-Sep-07 11:01

How to create a window handle.

8-Sep-07 11:01

Hi,

1.
yes I would use a Panel for this.

2.
I would also try and avoid scrolling.
What is the resolution of the tablet (how many points can it discern horizontally and
vertically) ? if that is less than there are pixels on the screen, I would do a one-on-one;
if the tablet resolution is quite different, I would use some scaling so it still fits
the (height of the) screen.

3.
Assuming a lot of data is coming in, I would use the bitmap approach: allocate a bitmap
of the right size, get a Graphics for it; then accept tablet input and paint into the
bitmap using that Graphics.

4.
New suggestion: don't Invalidate() everytime you modify the bitmap, just set a boolean flag.
Then install a Windows.Forms.Timer that ticks say once every 100 or 200 msec; in its
tick handler, if the flag is set, clear the flag and Invalidate the Panel.

As a result you can accept data at full speed, and your screen would be refreshed every
100 or 200 msec (rather than every time the bitmap changes).

Smile | :)

Luc Pattyn [Forum Guidelines] [My Articles]

RJGCarey6-Sep-07 7:36

6-Sep-07 7:36

All of my applications have migrated to VB 2005. They all start from Sub Main in a module.
Today I decided to create a new one and set "enable application framework" to true so that I can explore its new features.
The program has been run many times as I add new components. There have been no apparent problems.
I added code that creates a delegate to display the program's name and a date/time string as Form1's text.
It is invoked once a second by a thread spauned by my "Clock" class that runs on a background thread.
I encountered this error when it ran.
Invoke or BeginInvoke cannot be called on a control until the window handle has been created.
How does one create a handle for Form1?
Why wasn't it created automatically when the application started?
Thanks
RCarey

RCarey

Dave Kreskowiak6-Sep-07 7:43

6-Sep-07 7:43

RJGCarey wrote:
How does one create a handle for Form1?

You don't. It's automatically created.

The problem is caused by your code not waiting long enough for the window to be completely created. Basically, you're trying to update the window before it exists.

You can either delay starting your "Clock" class or, in the update code, check the Form's IsHandleCreated property before you try to update the Form.

A guide to posting questions on CodeProject[^]

Dave Kreskowiak
Microsoft MVP
Visual Developer - Visual Basic
2006, 2007

RJGCarey6-Sep-07 8:04

6-Sep-07 8:04

Private Sub Form1_Load(ByVal sender As System.Object, ByVal e As System.EventArgs) Handles MyBase.Load
Dim dbgS As String
bmpMain = New Bitmap(pbMain.Width, pbMain.Height)
AddHandler pbMain.Paint, AddressOf pbMain_Paint
bmpBars = New Bitmap(pbBars.Width, pbBars.Height)
AddHandler pbBars.Paint, AddressOf pbBars_Paint
instDelFormText = New delFormText(AddressOf FormText)
Shw.SetUp()
'error handling is now available
Try
MySql.Open()
Thread.Sleep(5000)
dbgS = Me.IsHandleCreated
Clock.Start()
Catch ex As Exception
Shw.Err("Form1_Load " & ex.Message)
End Try
End Sub

Put in the sleep. It does sleep.
put in dbgS. It Shows true.
Same error.
Thanks
RCarey

RCarey

Luc Pattyn6-Sep-07 8:10

6-Sep-07 8:10

Hi,

putting a Sleep in the main thread won't help, it just stops the world for a while,
nothing happens any more, no handles would get created in the mean time.

Where is it failing? Look at the line numbers in the Exception, and watch the line
numbers of your source code.(See my tips!)

Smile | :)

Luc Pattyn [Forum Guidelines] [My Articles]

RJGCarey6-Sep-07 9:44

6-Sep-07 9:44

Here's my code.
This code is in my 15+ other applications and it works all the time.

Form1
Private Sub Form1_Load
instDelFormText = New delFormText(AddressOf FormText)
End Sub
Public instDelFormText As delFormText
Public Delegate Sub delFormText(ByVal inText As String)
Private Sub FormText(ByVal inText As String)
Try
Me.Text = inText
Catch ex As Exception
Shw.Err("frmMain.WriteFormText " & ex.Message)
End Try
End Sub

Module Clock
Private Sub DoNewSecond()
Try
Form1.Invoke(Form1.instDelFormText, CObj("BarHunter 2005" & Space (100) & Now.ToString))
Catch ex As Exception
Shw.Err("Clock.DoNewSecond " & ex.Message)
End Try
End Sub

The failure occurs on Form1.Invoke etc
Thanks
RCarey

RCarey

Luc Pattyn6-Sep-07 9:53

6-Sep-07 9:53

Hi,

there is less code now than there was before in Form1_Load. The Form1 constructor is missing,
the Clock stuff is not complete.

Where do you start the clock? I would do it as the last thing in Form1_Load

Smile | :)

Luc Pattyn [Forum Guidelines] [My Articles]

RJGCarey6-Sep-07 11:46

How to call a procidure requiring arguments with new thread

6-Sep-07 11:46

My last post was just an abstract. The post prior to that has all the code. Starting the clock is the last thing in Form_Load.
In my other applications the form is created in Sub Main.
Here is the code.
Public Sub Main()
frmMain = New Form1 'new form
frmMain.Show() 'show it
Shw = New clsShow 'new class
Shw.SetUp() 'set up the graphics
cName = SystemInformation.ComputerName() 'get computer name
handleEndWorking = Now.ToString("yyyyMMdd") 'set the handleendworking
mySql = New clsMySql 'connect to the database
hntB = New BarHunter.clsBase 'new hunting base class
hntB.setUp = New BarHunter.clsSetUp 'new set up class
hntB.setUp.DoIt() 'do the job
hntB.setUp = Nothing 'dispose
Application.Run() 'run
End Sub
Now I just discovered that when I run my Show Procedures from another thread it doesn't work. It modifies a bitmap linked to a picture box on the form and then invalidates that picturebox.
Enable application framework sure creates a different critter.
Thanks
RCarey

RCarey

Amer Rehman6-Sep-07 6:50

Amer Rehman

6-Sep-07 6:50

Hi Can anybody tell me how can I call a procidure requiring arguments with a new thread. e.g. a code snippet like this.

Private Sub Button1_Click(ByVal sender As System.Object, ByVal e As System.EventArgs) Handles Button1.Click

Dim trShow As New Thread(AddressOf ShowMessage) 'error

End Sub

Sub ShowMessage(ByVal message As String)
MsgBox(message)
End Sub

Thanks for replying for a hobbyist progarmmer.

reman

Re: How to call a procidure requiring arguments with new thread

Dave Kreskowiak6-Sep-07 7:37

Re: How to call a procidure requiring arguments with new thread

6-Sep-07 7:37

Which version of VB.NET??

A guide to posting questions on CodeProject[^]

Dave Kreskowiak
Microsoft MVP
Visual Developer - Visual Basic
2006, 2007

RJGCarey6-Sep-07 7:47

CrystalReportviewer and Pagesetup

6-Sep-07 7:47

Create a new instance of a class passing parameters.
Create a new thread pointed at the sub in that class that does the work.
Name and start the thread. If you want you can wait till the thread finishes(Join) and then dispose of the instance of the class.
Here is a code snippet.

SQL.B.setDay = New SQL.clsSetUpAnyDay(Now.Date) 'new class
thdWorker = New Thread(AddressOf SQL.B.setDay.DoIt)'new thread
thdWorker.Name = "setDay" 'name it
thdWorker.Start() 'start
thdWorker.Join 'wait till it finishes
SQL.B.setDay = Nothing 'dispose

Hope that helps.
RCarey

RCarey

dcode256-Sep-07 4:56

dcode25

6-Sep-07 4:56

I have a Crystal report and a CrystalReportviewer and i want to put a button to open pagesetup for this report.In the CrystalReportViewer toolbar i see only a print , zoom and some other buttons but no Pagesetup.

Any idea
Thanks.

Re: CrystalReportviewer and Pagesetup

Lucky Sheikh6-Sep-07 20:17

Lucky Sheikh

6-Sep-07 20:17

hey guy
if u click on print button at cr report it will automatically display the pagesetup or print option
if u want to seprate add a button then write code
crrptview.printreport=true
hope u understand

lucky

Backups with Volume Shadow Copy Service (VSS) under vb.net

wtfia2k6-Sep-07 4:07

wtfia2k

6-Sep-07 4:07

Hi,

I'm trying for days now to figure out how to implement "Volume Shadow Copy Service" (VSS) under vb.net.
The goal is to get a tiny application the runs at XP, Vista and 2003 to make backups of files in use (locked).

I read almost the complete Internet and Google-Cache Wink | ;)

but didn't find any helpful startup-point. The "Volume Shadow Copy Service SDK 7.2" is C++ only, what's definitly not my language Sigh | :sigh:

Documentation can be found at: http://msdn2.microsoft.com/en-us/library/aa384961.aspx[]

Anybody out there that can give me a hint Confused | :confused:

Regards,

wtfia2k

Re: Backups with Volume Shadow Copy Service (VSS) under vb.net

Dave Kreskowiak6-Sep-07 4:42

Re: Backups with Volume Shadow Copy Service (VSS) under vb.net

6-Sep-07 4:42

Interesting.

Well, the documentation was written for a target audience of C++ developers, but that hardly makes the SDK "C++ only".

Though I can't find any VB.NET, or any other language, code samples, it's possible to use the VSS from VB.NET. Start by adding a COM Reference, in your VB.NET project, to the Volume Shadow Copy Service, then open the Object Browser and look through the Interop.VSS item listed in the browser.

You are venturing into uncharted waters here. You probably will not find any articles, samples, or knowledgable help on using VSS from your app.

A guide to posting questions on CodeProject[^]

Dave Kreskowiak
Microsoft MVP
Visual Developer - Visual Basic
2006, 2007

wtfia2k6-Sep-07 5:10

wtfia2k

6-Sep-07 5:10

Dave Kreskowiak wrote:
Interesting.

glad to here Smile | :)

Dave Kreskowiak wrote:
Though I can't find any VB.NET, or any other language, code samples, it's possible to use the VSS from VB.NET. Start by adding a COM Reference, in your VB.NET project, to the Volume Shadow Copy Service, then open the Object Browser and look through the Interop.VSS item listed in the browser.

that's exactly what I did - so far so good.
Thanks for acknowledging me.

Dave Kreskowiak wrote:
You are venturing into uncharted waters here. You probably will not find any articles, samples, or knowledgable help on using VSS from your app

I feared that unfortunately in such a way.

Regards,

wtfia2k

Re: Backups with Volume Shadow Copy Service (VSS) under vb.net

wtfia2k7-Sep-07 5:15

wtfia2k

7-Sep-07 5:15

Thanks again to Dave Kreskowiak who confirmed my idea to use the com-object "Volume Shadow Copy Service 1.0 Type Library".

After fooling around a bit with it I'm that far, that I really make Shadow Copies Big Grin | :-D

Here is the code how I've done it (in a quick and dirty manner, of course Blush | :O

)

Dim vshadow As New VSS.VSSCoordinator<br />
Dim snapshotSetID As System.Guid<br />
Dim _snapshotID As System.Guid<br />
<br />
vshadow.StartSnapshotSet(snapshotSetID)<br />
vshadow.AddToSnapshotSet(root, System.Guid.Empty, _snapshotID)<br />
<br />
Dim vssAsync As VSS.IVssAsync = Nothing<br />
Dim callback As Object = Nothing<br />
<br />
Debug.Write("starting shadow copy .")<br />
vshadow.DoSnapshotSet(callback, vssAsync)<br />
While True<br />
	Dim hr As Long<br />
	vssAsync.QueryStatus(hr, 0)<br />
	Debug.Write(".")<br />
	If DirectCast(hr, IVssAsyncQueryStatus) = IVssAsyncQueryStatus.VSS_S_ASYNC_FINISHED Then<br />
		Exit While<br />
	End If<br />
	Thread.Sleep(1000)<br />
End While<br />
Debug.Write(" done!")<br />
Debug.WriteLine("")<br />
<br />
Debug.WriteLine("examine snapshot")<br />
Dim snapshotProps As VSS._VSS_SNAPSHOT_PROP = Nothing<br />
vshadow.GetSnapshotProperties(_snapshotID, snapshotProps)<br />
<br />
Dim _snapshotDeviceName As String = snapshotProps.m_pwszSnapshotDeviceObject<br />
Debug.WriteLine("Shadow copy device name: " & _snapshotDeviceName)

So far - so good! But how to access the shadow copy to extract files out of it?

Trying someting like this:

Dim ShadowedRoot As String = Nothing<br />
vshadow.ExposeSnapshot(_snapshotID, Nothing, 1048576, "C:\ShdwOfC", ShadowedRoot)<br />
'vshadow.ExposeSnapshot(_snapshotID, Nothing, _VSS_VOLUME_SNAPSHOT_ATTRIBUTES.VSS_VOLSNAP_ATTR_EXPOSED_LOCALLY, "c:\ShdwOfC", ShadowedRoot)<br />
Debug.WriteLine("ShadowedRoot: " & ShadowedRoot)

crashes with an NotImplementedException.

What the he.. !!! Does this really mean, it's not implemented in the com yet, or am I doing something completely wrong? (a lot of wood, but now trees ...)

Regards,

wtfia2k

Re: Backups with Volume Shadow Copy Service (VSS) under vb.net

Dave Kreskowiak7-Sep-07 6:46