Re: error trying AVI creation, how to initialise out pointer? - Visual Basic Discussion Boards

gaxxx29-Jan-06 16:34

29-Jan-06 16:34

Thank you for your reply.
I am aware that the internet is full of code examples of ReadProcessMemory in C#, C++ ect, but I can never get the conversions to work, which is why I am looking for a code snippet in VB.net to work out where I have gone wrong.

Thanks again.

PS Is your application in VB.net?

Re: ReadProcessMemory API and VB.net

Mekong River29-Jan-06 20:35

Mekong River

29-Jan-06 20:35

gaxxx wrote:
but I can never get the conversions to work, which is why I am looking for a code snippet in VB.net

http://www.developerfusion.co.uk/utilities/convertcsharptovb.aspx[^]

Re: ReadProcessMemory API and VB.net

Duncan Edwards Jones29-Jan-06 21:08

Duncan Edwards Jones

29-Jan-06 21:08

There is a VB.Net declaration and use of ReadProcessMemory in http://www.thecodeproject.com/vb/net/VisualTraceListener.asp[^]

'--8<------------------------
Ex Datis:
Duncan Jones
Merrion Computing Ltd

Re: ReadProcessMemory API and VB.net

gaxxx30-Jan-06 3:50

gaxxx

30-Jan-06 3:50

Thank you Duncan,

I found your code elsewhere after I posted my original request.
It looks very interesting and hopefully the solution I am looking for.

Thanks all.

I

-- modified at 10:05 Monday 30th January, 2006

error trying AVI creation, how to initialise out pointer?

bskirkman29-Jan-06 13:46

bskirkman

29-Jan-06 13:46

I have tried the following code but get:
An unhandled exception of type 'System.NullReferenceException' occurred in WindowsApplication2.exe
Additional information: Object reference not set to an instance of an object

<br />
'public static extern int AVIFileCreateStream(int pfile, out IntPtr ppavi, ref AVISTREAMINFOW psi);  (C#)<br />
Declare Function AVIFileCreateStream Lib "avifil32" Alias "AVIFileCreateStream" (ByVal pfile As Int32, ByVal ppavi As IntPtr, ByRef lParam As AVISTREAMINFOW) As Int32<br />
<br />
Private _aviFile As Int32 = 0<br />
Private _aviStream As IntPtr<br />
<br />
Dim aviStreamInfo As AVISTREAMINFOW = New AVISTREAMINFOW()<br />
(then set some attributes)<br />
<br />
_result = AviFile.AVIFileCreateStream(_aviFile, _aviStream, aviStreamInfo)<br />

The problem occurs on the last line. This was part of my C# to VB conversion attempt of
http://www.codeproject.com/cs/media/aviFileWrapper.asp[^]
[^]

Re: error trying AVI creation, how to initialise out pointer?

bskirkman29-Jan-06 13:48

bskirkman

29-Jan-06 13:48

hmm, have to remove the stuff after .asp on that link thanks.

Re: error trying AVI creation, how to initialise out pointer?

Christian Graus29-Jan-06 16:48

Christian Graus

29-Jan-06 16:48

I'd say an out parameter also needs to be byref.

Christian Graus - Microsoft MVP - C++

Re: error trying AVI creation, how to initialise out pointer?

bskirkman29-Jan-06 17:08

bskirkman

29-Jan-06 17:08

problem still occurs with this, after changing to by ref, unless u meant change it another way?

<br />
        Private _aviFile As Int32  '(or = 0 as well)<br />
        Private _aviStream As IntPtr<br />
 Dim aviStreamInfo As AVISTREAMINFOW = New AVISTREAMINFOW() '(and fill some vals)<br />
<br />
Declare Function AVIFileCreateStream Lib "avifil32" Alias "AVIFileCreateStream" (ByVal pfile As Int32, ByRef ppavi As IntPtr, ByRef lParam As AVISTREAMINFOW) As Int32<br />
<br />
 _result = AviFile.AVIFileCreateStream(_aviFile, _aviStream, aviStreamInfo)<br />

thanks

machine vision

Georgekutty29-Jan-06 9:12

Georgekutty

29-Jan-06 9:12

I wish to make an object tracking algorithm.
My aim is to identify the finger by a web cam
and control the mouse pointer corresponding
to the movement of the finger.
can you help me to complete this poject?
please inform about the active x control
that can be used for this purpose

thanks for informations

Re: machine vision

Christian Graus29-Jan-06 15:45

Christian Graus

29-Jan-06 15:45

Georgekutty wrote:
please inform about the active x control
that can be used for this purpose

In other words, you hope that someone else has written the code to do this, and you can just call it ? That means you have no desire at all to make an 'object tracking algorithm'.

Christian Graus - Microsoft MVP - C++

can you help me,,,about data grid ?

flashmemory29-Jan-06 2:47

flashmemory

29-Jan-06 2:47

my data is loaded to data grid using dataset,,
now i want to put a button when i press on it it will save the changes permanent to my database...

thanks...

Re: can you help me,,,about data grid ?

Christian Graus29-Jan-06 15:46

Christian Graus

29-Jan-06 15:46

You can iterate through the rows of a datagrid and check if a row is new, if it was deleted, or if it's been changed. Once you do this, you'll know what data to pass back to the database.

Christian Graus - Microsoft MVP - C++

Re: can you help me,,,about data grid ?

Mekong River29-Jan-06 20:37

Mekong River

29-Jan-06 20:37

Christian Graus wrote:
You can iterate through the rows of a datagrid and check if a row is new, if it was deleted, or if it's been changed. Once you do this, you'll know what data to pass back to the database.

How could we do that?

Re: can you help me,,,about data grid ?

Christian Graus30-Jan-06 9:14

Christian Graus

30-Jan-06 9:14

http://www.vb-helper.com/howto_net_datagrid.html[^]

This example shows how to use a data adapter to do the same thing.

Christian Graus - Microsoft MVP - C++

Re: can you help me,,,about data grid ?

Mekong River3-Feb-06 5:32

Mekong River

3-Feb-06 5:32

Thank you very much for your answer.

How can I detect if any deviced plugged or unplugged to USB port?

JUNEYT29-Jan-06 1:54

JUNEYT

29-Jan-06 1:54

Hello!

It is me again! Frown | :(

Could you please let me know how I could detect a plugged or unplugged deviced to usb port? A code sample would make me happier..

Thank You!

Bedri

Re: How can I detect if any deviced plugged or unplugged to USB port?

progload29-Jan-06 7:02

progload

29-Jan-06 7:02

There is a few different ways, depending on what type of device it is:

http://msdn.microsoft.com/coding4fun/someassemblyrequired/isthatyou/default.aspx[^]

http://msdn.microsoft.com/msdnmag/issues/02/10/CuttingEdge/[^]

http://www.dotnet247.com/247reference/msgs/43/217435.aspx[^]

http://www.codecomments.com/archive291-2004-4-185490.html[^]

progload

displaying results

sentmemail29-Jan-06 1:28

sentmemail

29-Jan-06 1:28

Hi,
In VB.net, how can i know the results of Obj.GetText without running the code and using messagebox to display it?
thanks

Re: displaying results

Dave Kreskowiak29-Jan-06 7:51

Dave Kreskowiak

29-Jan-06 7:51

You either have to know the object that you calling GetText on very, very well, or consult a Ouji board.

Other than that, the best way is to step through the code in the debugger and watch what happens to the variable contents.

RageInTheMachine9532
"...a pungent, ghastly, stinky piece of cheese!" -- The Roaming Gnome

Updating a datagridview

trimtrom29-Jan-06 0:12

trimtrom

29-Jan-06 0:12

Hello

I am new to VB.net and have a form where I am trying to update an Access database from a datagridview that I databound on the fly. However when I change something on the grid and press the update button it would seem that the dataset has accepted the changes, but when I next look at the grid, it hasn't updated. Can I use a SELECT statement in the way that I have?

Am I doing something wrong in the code, or is there something in the grid properties that I need to change?

Many thanks

Trimtrom

Public Class frmManual
Dim dcManual As New OleDb.OleDbConnection("Provider=Microsoft.Jet.OLEDB.4.0;Data Source=|DataDirectory|\Nwind 97.mdb")
Dim daManual As OleDb.OleDbDataAdapter
Dim dsManual As New DataSet
Dim strSQL As String

Private Sub frmManual_Load(ByVal sender As System.Object, ByVal e As System.EventArgs) Handles MyBase.Load

strSQL = "select * from employees"
Try
daManual = New OleDb.OleDbDataAdapter(strSQL, dcManual)
daManual.Fill(dsManual, "Employees")
Catch ex As Exception
MsgBox(ex.Message)
End Try
Me.dgManual.DataSource = dsManual.Tables("Employees")
End Sub

Private Sub cmdUpdate_Click(ByVal sender As System.Object, ByVal e As System.EventArgs) Handles cmdUpdate.Click
Dim ans As String
If (dsManual.HasChanges) Then
ans = MsgBox("Changes have occurred!" & vbCrLf & "Do you wish to update?", MsgBoxStyle.YesNo + MsgBoxStyle.Information, "Updates")
If ans = vbYes Then
Try
dsManual.AcceptChanges()
daManual.Update(dsManual.Tables("Employees"))
Catch exManual As Exception
MsgBox(exManual.Message)
Throw exManual
Finally
End Try
MsgBox("Table updated!", MsgBoxStyle.Critical, "Employees")
End If
End If
End Sub
End Class

Print Preview

Saeid Jorablo28-Jan-06 23:31

Saeid Jorablo

28-Jan-06 23:31

Dear All
Hello, How can make a print preview in VB6.0 with API and VB functions. Without any Other .OCX Files.

How can I resize a big image and then save it in smaller size?

JUNEYT28-Jan-06 8:55

JUNEYT

28-Jan-06 8:55

Hello!

I have a picturebox (width=60, Height=60) size mode is set to Strechimage. I am loading an image to picturebox which has bigger size and then I want to save this image back to hard disk with smaller size (size of picturebox)?

Can you show me how to do that please?

Thanks!

Bedri

Re: How can I resize a big image and then save it in smaller size?

Guffa28-Jan-06 11:42

Guffa

28-Jan-06 11:42

VB or VB.NET?

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Re: How can I resize a big image and then save it in smaller size?

JUNEYT28-Jan-06 20:03

JUNEYT

28-Jan-06 20:03

VB.NET

Re: How can I resize a big image and then save it in smaller size?

Guffa29-Jan-06 9:59

Guffa

29-Jan-06 9:59

Use the GetThumbnainImage method of the Image class.

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b { font-weight: normal; }

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