Visual Basic

communication with I2C Adapter

6-Aug-04 3:04

What you ask is not so straight forward. It really depends on the type of .DLL your trying to use (C++ function library or a COM .DLL). Also, you'll need some kind of documentation on the .DLL. Otherwise, you'll have a very difficult time using it. You'll be able to see the function names using the Depends utility that comes with Visual Studio 6, but you can't see the return types or the parameters for each function. There is no way to determine that just by looking at the .DLL exports. You NEED the documentation on it...

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

sumiko5-Aug-04 21:11

sumiko

5-Aug-04 21:11

hi, anybody know the visual basic coding for the communication with the I2C adapter, inculding the read and write command. It are using USB to communicate with the I2C. Anyone can give advice? thanks.

Re: communication with I2C Adapter

Dave Kreskowiak6-Aug-04 3:00

Re: communication with I2C Adapter

6-Aug-04 3:00

You would have much better luck on Google. I tried "I2C VB" and came up with an OCX Control that might work for you.

Without any documentation on the workings of the adapter, you'll find the job of communicating with the adapter through it's drivers impossible.

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

sumiko10-Aug-04 20:43

sumiko

10-Aug-04 20:43

Thanks for your information. The suggestion given by you is for the parallel port. But my communication is using USB to connect the I2C Adapter. So can you give me some information about this? Thanks.

Re: communication with I2C Adapter

Dave Kreskowiak11-Aug-04 1:15

Word PrintPreview to Jpeg

11-Aug-04 1:15

Now you have mo choice but to go through the adapters driver. WIthout the docs on the drivers exposed API, you'll find this impossible. You might want to check this[^] out for docs and stuff.

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

Anonymous5-Aug-04 14:26

Anonymous

5-Aug-04 14:26

Is there any way to acces printpreview image and convert it to jpeg
file in MS Word?

Shin

Re: Word PrintPreview to Jpeg

Dave Kreskowiak6-Aug-04 2:56

List Views containing Custom objects

6-Aug-04 2:56

It's going to be a big PITA to do. There is no one call you can make you get an image from the screen. This will require in-depth knowledge of Windows and the Win32 API.

You'll have to write code to find the instance of Word you want, find the window for the print preview image (not the print preview dialog!), get a handle to that window, convert that handle to a Graphics object (assuming VB.NET here, VB6 - forget it), use the Graphics object to save the image in JPEG format, then release your objects and handles.

Do I have any example code? NO! You can Google for pieces of this process, but you more than likely won't find an app written for you.

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

kowplunk5-Aug-04 10:00

kowplunk

5-Aug-04 10:00

Is there no way to make list Views bahave to like list boxes in allowing an object to be inserted, and then having the overrided toString() method output the text that is to be displayed in the list. I can't get it to work, and I can't find anything written on it, so I just want to check.

Thanks for the help.

Re: List Views containing Custom objects

kowplunk5-Aug-04 15:45

kowplunk

5-Aug-04 15:45

instead I just inserted all the required data into the list view and set the widths to zero. I am not sure if this is the best way or not, but it works.

Generic Custom Data Source For Data Grid

toddmo5-Aug-04 7:47

toddmo

5-Aug-04 7:47

I want to take tabular data from a source that has no .NET provider.
So I want to create a custom datasource for my datagrid,
which will read the data from the source and feed it to the grid.
I have not seen any examples on how to do this.
I won’t know the data elements (column names) in advance, so I **can’t hard code anything**.
The columns, properties, attributes or whatever that the grid is binding to will have to be built at runtime.

If you take the custom data set examples available on the web, you would have to create a new custom datasource object for each "query", because the examples bind the datagrid to properties on a specific object!

Now, the DataAdapter object will fill a DataSet, and I made a custom DataAdapter for my source to do just that.

But it's too slow, doing twice as much work. The data is read into the DataSet, and then into the DataGrid.

I need it to go straight into the grid from the source. It's a speed requirment.

So, to distill this into it's simplist terms, I need something like this (not necessarily this) (forgive syntax errors):

Dim MyDataSource as New MyDataSource()

MyDataSource.Add("Name",New String(){"Jim","Bill","Joe"})
MyDataSource.Add("ID",New String(){"221","321","442"})
MyDataSource.Add("Rank",New String(){"1","3","2"})

grdDataGrid.DataSource = MyDataSource

The result is a grid populated with three columns - Name, ID and Rank, having 3 rows, one for each person.

Actually, the DataGrid will interrogate the datasource for each new row of data, but the columns don't come from properties or attributes, they need to come from items in a collection.

If I can learn how to do that, I can do anything with data binding.

If the solution is Reflection.Emit, I'm fine with that; I was hoping for a more direct way.

Thanks,
Todd

how can I close .exe in multiple forms?

Lisana5-Aug-04 4:59

5-Aug-04 4:59

I have 3 forms in my project, each form has 3 button to call each form.
the main form is form1, when button2 click, I used form2.show, and form1.hide, form3.hide..
my problem is: when I close form2 (that close the project), my form1.exe is still running. how do I code .exe to close when I close the project?

is there someone know how to fix this problem?

Thanks!
-Lisa

Colin Angus Mackay5-Aug-04 6:05

5-Aug-04 6:05

You can create an event handler for the Closing event which occurs when the user clicks the X in the top right corner but before the form is actually closed. The EventArgs for this particular event has a Cancelled property that can be set to true and from then you can implement your own behaviour. If you want to reopen the previous form you may not want to cancel the close event but just reopen the previous form and the application should continue running as there is an open form still.

Does this help?

"If a man empties his purse into his head, no man can take it away from him, for an investment in knowledge pays the best interest." -- Joseph E. O'Donnell

Can't manage to P/Invoke that Win32 API in .NET? Why not do interop the wiki way!

Lisana5-Aug-04 6:45

5-Aug-04 6:45

thanks, it seems so easy to do it. but I don't have any idea to code the event handler. Can you pls show me some example codes? I just want to close the .exe when I click X to close form1 or form2 or form3..and it only shows one form at a time.

I very appreciate your help so much.
-Lisa

Lisana5-Aug-04 8:01

5-Aug-04 8:01

I code this code into my 3 forms..but the .exe still not close in my taskManger processes..do you know why?

here is my code:

Private Sub FormClosing(ByVal sender As System.Object, ByVal e As System.ComponentModel.CancelEventArgs) Handles MyBase.Closing

If MessageBox.Show("Are you sure to exit?", "Exit", MessageBoxButtons.YesNo, MessageBoxIcon.Question) = DialogResult.Yes Then
e.Cancel = False
Else
e.Cancel = True
End If

End Sub

Thanks!

-Lisa

Colin Angus Mackay5-Aug-04 10:15

5-Aug-04 10:15

Okay - Looks like you've figured out the event handler bit. In your previous post you mention that you just hide the other forms. Make sure they get closed also.

To do this you can call the Close() method on each of the hidden forms. But this will have the effect of raising the Closing event - so you would end up with multiple dialogs to the user asking "Are you sure you want to exit?".

As you are closing the whole application. You could consider Application.Exit() which will not call the Closing or Closed events on any open forms.

Does this help?

Lisana5-Aug-04 10:44

5-Aug-04 10:44

Thanks -- it makes much sense to me now..

But I don't know where I need to call the application.exit()?
so if I use the application.exit(), does that mean I don't need the event handler now?

-Lisa

Colin Angus Mackay5-Aug-04 10:56

5-Aug-04 10:56

By the looks of it you would call the Application.Exit() from within the event handler, as this code is asking the user if they are sure that they want to exit.

Your event handler might look something like this:

Private Sub FormClosing(ByVal sender As System.Object, ByVal e As 
                        System.ComponentModel.CancelEventArgs) Handles MyBase.Closing

    If MessageBox.Show("Are you sure to exit?", "Exit", MessageBoxButtons.YesNo,
                       MessageBoxIcon.Question) = DialogResult.Yes Then
        Application.Exit()
    Else
        e.Cancel = True
    End If

End Sub

It will ask the user if they are sure they want to exit the application, and if they choose yes the Application will exit. IIRC no further events will be handled and definitely the Closed and Closing events of the other forms will not get raised.

Does this clear everything up?

Lisana5-Aug-04 11:04

5-Aug-04 11:04

wow..It works Smile | :)

Love you so much! Thank you very much!
this problem drives me crazy everyday when I run the project..
It's all fixed now..I'm so happy...^_^...
I will give you a very big hug if you are here... Smile | :)

Colin Angus Mackay5-Aug-04 13:29

more on environment variables

5-Aug-04 13:29

Lisana wrote:
Love you so much! Thank you very much!
I will give you a very big hug if you are here...

Blush | :O

Wow! That's more praise than I usually get when helping out... I really appreciate it.

madfiddlerchris5-Aug-04 4:18

madfiddlerchris

5-Aug-04 4:18

Some of you may have read my postings on this recently

http://www.codeproject.com/script/comments/forums.asp?msg=880420&forumid=1646&XtraIDs=1646&searchkw=environment+variable&sd=5%2F7%2F2004&ed=8%2F5%2F2004#xx880420xx

However, I am still having issues.

If I start my windows application and then define some environment variables, then propagate them up to the system level - then I start a commans prompt window for example and use the SET command I can see the new/changed environment variables.

My applciation then loads an unmanaged DLL (written in C which performs a JNI function). The first function call to this attempts to read environment variables that I have set in the my .NET windows application but they do not seem to be inherited.

What appears to happen is that the unmanaged DLL (even though I load it dynamically only just before using its functions) inherits the environment that was available when the .NET windows application first started.

So if I shut down my applicaiton, manually declare environment variables in Windows, run my .NET app again and this time skip over the code that sets the environment variables, the unmanaged DLL functions are able to read the environment variables no problem!

Does this make sense?
I also found reference to this problem here in some archived usenet stuff, but no solution Blush | :O

(
http://usenet.best-buy-online.com/Dir8/File985.html

I am not a C programmer and the unmanaged DLL has been written by someone else. Could there be anything in the compilation of the DLL that affects how the environment is inherited. I believe the DLL is written using Visual Studio C++ v6

Unfortunately I HAVE to set the variables in the .NET windows application. Can anyone think of a way around this or does anyone know of an alternative solution?

thanks

Dave Kreskowiak5-Aug-04 7:29

5-Aug-04 7:29

This shouldn't be a problem if your machine is patched up with current service packs.

What does the code look like where you set the environment variables for YOUR application, not the system. A .DLL loaded by your app will not inherit the environment from anywhere. When loaded, the code from the .DLL becomes part of your app's process space and, thereby using the same copy of the enivorment used by your application. You could call it inheriting, but that's not what is really happening.

If your app, or your .DLL loaded by your app, spawns a child process, this child process will inherit the environment from your app.

We need to see the code your using!

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

madfiddlerchris25-Aug-04 0:31

madfiddlerchris

25-Aug-04 0:31

Dave, thanks for your help so far.

First of all I'm using Windows 2000 and have SP4 installed.

The code that I use for setting the environment variables is as per my previous posting...
http://www.codeproject.com/script/comments/forums.asp?msg=880420&forumid=1646&XtraIDs=1646&searchkw=environment+variable&sd=5%2F7%2F2004&ed=8%2F5%2F2004#xx880420xx

This sets the environment variables for the windows system AND then for my application via a call to SetEnvronmentVariableA in kernel32.dll

AFTER all the environment variables have been set I can open a command prompt and see them, or I can use Debug.Print Environ("my_var") in the command window of visual studio and see that they are set

Also AFTER the environment variables are set I then load my unmanaged DLL dynamically using the LoadLibrary function of kernel32.dll

I have scoured the net and seen other people state that the environment that the dynamically loaded DLL inherits will be that set when the .NET application is first loaded, but have not seen any solutions to this if this is true.

However, as mentioned before I have an older version of the unmanaged DLL that seems to pick up the environment variables fine even when only using SetEnvironmentVariableA and not propagating them to the Windows system. This is why I was starting to think there may be something in the way the DLL is compiled. Problem is I can't stick with the older version of the DLL and some new stuff has been added to the current version which I am reliant upon.

Dave Kreskowiak26-Aug-04 1:33

26-Aug-04 1:33

I seem to remember that there was a problem in Windows 2000 with Environment Variables, but I can't remember what. It was fixed in Service Pack 3, I think. That could be why it worked for a previous version and not now. I has nothing to do with how your .DLL was compiled.

The changes you're making in the environment are taking effect in everything else, but I don't think they are taking effect in your application before you load your .DLL. To test this, you'll have to make your app make the changes in the System Environment and broadcast the WM_SETTINGCHANGE message. Make sure the changes took by launching a command prompt and dumping the environment strings with the SET command. The next thing your app has to do is dump all of it's environment settings with the System.Environment class:

Imports System
Imports System.Collections
.
.
.
    Dim envVars As IDictionary = Environment.GetEnvironmentVariables()
    Dim de As DictionaryEntry
    For Each de In envVars
        Debug.WriteLine(de.Key & " = " & de.Value)
    Next

If these two lists match, you're in business. If not, it means that your application isn't picking up the system variables. A work around would have to be devised...

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