Downloading files with Webrequest - C# Discussion Boards

Christian Graus11-Nov-02 0:05

11-Nov-02 0:05

I have been playing with ADO.NET and my connection object returns me a OleDbDataReader. How do I turn that into something I can bind to the DataGrid ?

Thanks for any suggestions.

Christian

No offense, but I don't really want to encourage the creation of another VB developer. - Larry Antram 22 Oct 2002

Hey, at least Logo had, at it's inception, a mechanical turtle. VB has always lacked even that... - Shog9 04-09-2002

During last 10 years, with invention of VB and similar programming environments, every ill-educated moron became able to develop software. - Alex E. - 12-Sept-2002

Re: DataGrid ???

James T. Johnson11-Nov-02 3:00

James T. Johnson

11-Nov-02 3:00

Use the DataAdapter's Fill method to fill a DataSet then set the DataSource property of the grid to the DataSet you just filled.

~~[edit]Sorry its early, i'll get back with you on how to do it [/edit]~~

It pays if I look at the right class in the framework, use the OleDataAdapter class, passing in your OleDbCommand object; then use one of the Fill methods.

James

- out of order -

Re: DataGrid ???

leppie11-Nov-02 6:27

leppie

11-Nov-02 6:27

Hi
To add the James's response, the DBAdapter has a wonderfull Configure button Smile | :)

Takes care of almost everything, but you mite need to modify the statements or procudures to your liking.

DataSets are really good timesavers Smile | :)

, but there is a performance overhead (not that its really noticable on my PC anyways)

Cheers Smile | :)

"I dont have a life, I have a program."

.NET Training Institute

ReachAnshul10-Nov-02 19:30

ReachAnshul

10-Nov-02 19:30

Hi Guys,
I am looking for .NET training institute in bay area (Sunnywale,Santa clara or Fremont).
Please let me know if you know one.
Thanks
Anshul

Re: .NET Training Institute

Christian Graus10-Nov-02 19:43

Christian Graus

10-Nov-02 19:43

Several people at work have done .NET courses. My advice - buy Programming the .NET Framework, Inside C#, and the ADO.NET and ASP.NET books from Microsoft. You'll learn more and it will cost less.

Christian

No offense, but I don't really want to encourage the creation of another VB developer. - Larry Antram 22 Oct 2002

Hey, at least Logo had, at it's inception, a mechanical turtle. VB has always lacked even that... - Shog9 04-09-2002

During last 10 years, with invention of VB and similar programming environments, every ill-educated moron became able to develop software. - Alex E. - 12-Sept-2002

BindingsCollection

Alan Todtenkopf9-Nov-02 11:19

Alan Todtenkopf

9-Nov-02 11:19

I am unsuccessful in inheriting from this class. ControlBindingsCollection inherits from it and it has protected internal members implying it was designed to be inherited from. Yet, the compiler says there is no access to the constructor and the object browser does not show a constructor.

Alan

Re: BindingsCollection

James T. Johnson9-Nov-02 11:25

James T. Johnson

9-Nov-02 11:25

Shawn Wildermuth *just* answered your question, but I'll repost it here for those not on the DOTNET-WINFORMS[^] mailing list.

"The constructor is marked internal...that's how the ControlBindingsCollection inherits from it."

James

- out of order -

Downloading files with Webrequest

Anonymous9-Nov-02 7:40

Anonymous

9-Nov-02 7:40

How do I determine when to stop reading from the response stream on a webrequest? It seems that if I do
while (bytesread > 0)
bytesread = bufferedrdr.Read(buffer, 0, buffer.Length);

I'll get incomplete files. Looks like the stream returns 0 bytes read whenever the internet connection lags. Most of the example code does use a 0/-1 return code to determine when to stop reading.

The read method doesn't wait until there is new data in the stream does it? Confused as to how to determine when the end of the file is downloaded.

Re: Downloading files with Webrequest

Stephane Rodriguez.9-Nov-02 8:10

Stephane Rodriguez.

9-Nov-02 8:10

It uses an asynchronous callback system. More info here[^].

Back to real work : D-21.

Re: Downloading files with Webrequest

Anonymous9-Nov-02 9:17

Anonymous

9-Nov-02 9:17

Is there any adavantage of using begininvoke/endinvoke? I already have each download running in a seperate thread.

Re: Downloading files with Webrequest

Stephane Rodriguez.9-Nov-02 9:25

Stephane Rodriguez.

9-Nov-02 9:25

Anonymous wrote:
Is there any adavantage of using begininvoke/endinvoke?

I am afraid not since that's what is done already. By the way, you should also know that the underlying connection is multi-threaded too (with an upperbound I can't remember at the moment).
I believe the only way to cope with the problem you are facing is to write your own httpweb request stuff. The funny thing is the http web request itself is bad only because it doesn't provide configuration capabilities over the underlying connection. There is a lot of application logic underneath.
Which is equivalent to say the people at MS who created it thought developers were ready to do web requesting on a fire and forget basis. That's a stupid assumption of course...

Back to real work : D-21.

Again dialog ... :(

Karavaev Denis9-Nov-02 5:29

Karavaev Denis

9-Nov-02 5:29

Ok, thanks everyone, but I have one more question.
To gett callback of my modal dialog I use this code:

ModalDlgClass myDlg = new ModalDlgClass();
if(myDlg.ShowDialog() == DialogResult.OK)
{
//Do smf.
}

But in the modal dialog there is a small problem ...
I need to check something before close it.

if(textBox1.Text.Length == 0)
{
//cheking and need returf focus to modal dialog
}
else
{
//do smf else, then
this.Close(); // I need 2 close it ONLY if textBox1 is not emty
}

But if my textBox1 is empty after checking modal dialog is closing ... is there any way not to close it?

thanks

=====================
http://wasp.elcat.kg

Re: Well...

Masaaki Onishi10-Nov-02 7:15

Masaaki Onishi

10-Nov-02 7:15

Hello, the codegurus around the world.;)

If you work for MFC, you will figure it out.
Maybe, you just declare MyDialog_OnClose message method, and filter
the textbox input.
And, if there is no input, just return before the base class Close is called.
Just put "return".
I believe that this works.

Please, don't send me your email about your questions directly.
Have a nice day!
Sonork - 100.10571:vcdeveloper Wink | ;)

-Masaaki Onishi-

Re: Well...

Karavaev Denis10-Nov-02 16:36

Karavaev Denis

10-Nov-02 16:36

I deed, but it, not working.
I have modal dialog. And it's closing even if i put 'return'.
Maybe it is becourse I click on button with 'OK' dialog properties?
But is it only way to get response from my Modal dialog?

=====================
http://wasp.elcat.kg

Re: Ooops.

Masaaki Onishi10-Nov-02 17:29

Masaaki Onishi

10-Nov-02 17:29

Hello, the codegurus around the world.;)

Oooops, you're right because I got the same result.
So, I asked "HELP" of VC#.

1) Use DialogResult.NONE

protected void btnOK_Click (object sender, System.EventArgs e)
{
        // OK button clicked.
	// get new message.
	strMessage = txtMessage.Text;

	if(strMessage == "") 
	{
		MessageBox.Show(this, "Error");
		DialogResult = DialogResult.None;
	}
}

2) Disable OK button if TextBox is empty

private void Msg_TextChanged(object sender, System.EventArgs e)
{
   if(txtMessage.Text == "")
	btnOK.Enabled = false;
   else
	btnOK.Enabled = true;
}

Please, don't send me your email about your questions directly.
Have a nice day!
Sonork - 100.10571:vcdeveloper Wink | ;)

-Masaaki Onishi-

Re: Ooops.

Karavaev Denis11-Nov-02 2:36

Karavaev Denis

11-Nov-02 2:36

Yah!!! thanks,

Nice idea to lock button till text is empty! Wink | ;)

=====================
http://wasp.elcat.kg

Re: Again dialog ... :(

mikasa11-Nov-02 6:52

mikasa

11-Nov-02 6:52

I had to do this in VB.NET. What I did was I didn't "HardCode" the "Dialog Result Codes" into my Command Buttons. When the User clicked the "Login" Button of my Form, I would Validate the Login info, if it was Correct, I would just Type "Return DialogResult.OK", otherwise I would not return anything.

A simple function pointer question...

Dave Kerr9-Nov-02 0:40

Dave Kerr

9-Nov-02 0:40

Hi I'm havinh real trouble using this one OpenGL function I'm trying to import into my app. The C function is declared as this:-

void gluTessCallback(GLUtesselator* obj, GLenum type, void(*fn)());

I know that GLUtesselator* is basically just an IntPtr, as I've imported other functions with it in, and they've worked fine. Similarly, GLenum is just a UInt. But what do I do with the void function pointer?
I have declared delegates for all of the possible function types it could be, (depending on the 'type' variable), but I don't know where to go from there.

MSDN only has info for function pointers that are always a set type, but with this function, the pointer can be to a number of different types of function.

Please help me out here!

Thanks in advance
Dave

Dave Kerr
focus_business@hotmail.com
www.focus.esmartweb.com

Re: A simple function pointer question...

beetung9-Nov-02 1:13

beetung

9-Nov-02 1:13

Dave Kerr wrote:
declared as this:-

void gluTessCallback(GLUtesselator* obj, GLenum type, void(*fn)());

....
I don't know where to go from there.

Is C# really that much different from C++??

//declaring three variables
GLUtesselator* gPtr =...;
        GLenum gType =...;
        void(* gFuncPtr  )(void);
        gFuncPtr = ...;

// call the function
gluTessCallback(gPtr, gType, gFuncPtr);

wont compile under C#??

Re: A simple function pointer question...

Stephane Rodriguez.9-Nov-02 2:50

Stephane Rodriguez.

9-Nov-02 2:50

Did you give a look at this[^] ?

To ease the marshaller's job, you may also add this attribute : [MarshalAs(UnmanagedType.FunctionPtr)]

Back to real work : D-21.

MDI application

Le centriste8-Nov-02 17:43

Le centriste

8-Nov-02 17:43

is it possible to build an MDI application in C#, especially using VS.NET?

Michel

It is a lovely language, but it takes a very long time to say anything in it, because we do not say anything in it, unless it is worth taking a very long time to say, and to listen to.

- TreeBeard

Re: MDI application

Stephane Rodriguez.8-Nov-02 19:37

Stephane Rodriguez.

8-Nov-02 19:37

You've got a MDI sample written in C# in your .NET framework samples : SDK\Samples\Quickstart\Winforms\samples\mdi.

Back to real work : D-21.

Re: MDI application

Le centriste9-Nov-02 7:33

Le centriste

9-Nov-02 7:33

Tx. but I found this in MSDN

ms-help://MS.VSCC/MS.MSDNVS/vbcon/html/vbconMDIApplications.htm[^]

NOTE: You must have MSDN installed to follow this link. If not:

http://msdn.microsoft.com/library/default.asp?url=/library/en-us/vbcon/html/vbconmdiapplications.asp[^]

Michel

It is a lovely language, but it takes a very long time to say anything in it, because we do not say anything in it, unless it is worth taking a very long time to say, and to listen to.

- TreeBeard

Re: MDI application

Eric Gunnerson (msft)11-Nov-02 7:44

Eric Gunnerson (msft)

11-Nov-02 7:44

If you go to http://www.csharp.net, in the 'Code' section there's a library that I think does this. IIRC, it's called Genghis.

FileSize

kavehdr8-Nov-02 12:08

kavehdr

8-Nov-02 12:08

Hi, Does anyone know here how to make a file with C# that has a wrong size. Say 10TB, but a single file that actually only takes a few bytes on the drive?

Thanks

K.D.

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