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I wanna provide a MC++ lib for C# user. One function is: bool ReadString(string str)
I must write it in MC++ for some former code ReadBuffer.
I write it like something below, but failed in get the StringBuilder or String's char buffer. The marshal must be something wrong, can't pass the compiler.
bool ReadString(String * &str)
{
void * pBuffer;
int num;
ReadBuffer(&pBuffer, num);
StringBuilder* sb = new StringBuilder(64*1024);
MultiByteToWideChar(0,0,pBuffer, num, [MarshalAs(UnmanagedType.LPWStr)]sb, 64*1024);
str = sb->ToString();
}
Can anything lend me a hand?
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I think this would be better asked in the MC++ forum. 
I don't know whether it's just the light but I swear the database server gives me dirty looks everytime I wander past.
-Chris Maunder
Microsoft has reinvented the wheel, this time they made it round.
-Peterchen on VS.NET
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novachen wrote:
I wanna provide a MC++ lib for C# user. One function is: bool ReadString(string str)
Do you mind if I ask why you are writing a library in MC++ to read a string. This can easily be done in C#, especially if other parts of the project will be written in C#. Could you provide further info?
Nick Parker
Not everything that can be counted counts, and not everything that counts can be counted. - Albert Einstein
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Nick Parker wrote:
Do you mind if I ask why you are writing a library in MC++ to read a string.
In fact, the function is provided for a gzip lib. My ReadString's function is extract the text from the gz file. And because the dotnet use the Unicode char, i have to transform single byte into unicode (double bytes form). So the win32 api is used. When use the API, the address of buffer must provided, so i need some marshal on the String or StringBuilder.
Did i say it clearly now  ?
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novachen wrote:
Did i say it clearly now
yep - I knew I had an article bookmarked for something like this. Check out Mixing Managed and Unmanaged code[^]. Hope this helps.
Nick Parker
Not everything that can be counted counts, and not everything that counts can be counted. - Albert Einstein
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i had host a email web service on a win2000 server. one of the parameter of the web service method call is "string filename". this "filename" will passed into
System.Web.Mail.MailAttachment class constructor to send email.
now, i have another standalone application which run on win98 computer. my standalone application want to send a image file which located in win98 computer.
can i just call the web service ws.SendMail("yccheok@yahoo.com", "c:\live.jpg"); without first explicit transfer the image file to win2000 server?
thank you.
regards
yccheok
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No, you can't do that. What you can do however is use the new Web Services Development Kit and read this article on DIME[^] to do what you want.
I don't know whether it's just the light but I swear the database server gives me dirty looks everytime I wander past.
-Chris Maunder
Microsoft has reinvented the wheel, this time they made it round.
-Peterchen on VS.NET
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previously, i had an application that use a COM object to grap image from web cam. i try to enhance my application by using the Windows Media Encoder 9 Series SDK to do live video streaming.
i realize that whenever i stop my image capturing thread and run WM live video streaming thread, my application has no problem at all the access the web cam device. however, whenever i try to stop WM live video streaming thread, the COM object unable the use the web cam device. it seems that the camera device still hold by the WM thread. the WM thread goes like this......
-----------------------------------------------------------------------
public void StartWM()
{
if(WMThread != null)
{
if(WMThread.IsAlive)
{
StopWM();
}
}
if(cameraThread != null)
{
if(cameraThread.IsAlive)
{
StopCamera();
}
}
WMThread = new Thread(new ThreadStart(_StartWM));
WMThread.Priority = ThreadPriority.Lowest;
WMThread.Start();
}
public void StopCamera()
{
if(cameraThread != null)
{
cameraThread.Abort();
while(cameraThread.IsAlive);
cameraThread = null;
}
}
public void StopWM()
{
if(WMThread != null)
{
WMThread.Abort();
while(WMThread.IsAlive);
WMThread = null;
}
if(Encoder != null)
{
Encoder.Stop();
//HOW TO MAKE SURE ENCODER
//IS COMPLETELY RELEASE ITS //WEB CAM DEVIDE HANDLE
//BEFORE IT PROCEEDS TO
//NEXT //STATEMET???????
//while(Encoder.IsAlive); <-
//- of course this
//wont work
Encoder = null;
}
}
private void _StartWM()
{
try
{
// Create WMEncoderApp and WMEncoder objects.
if(Encoder == null)
{
Encoder = new WMEncoder();
}
//encoder initialize
//code goes here for live
//video
//broadcasting
//Start the encoding
//process.
Encoder.PrepareToEncode(true);
Encoder.SynchronizeOperation = false;
Encoder.Start();
}
catch(Exception ex){}
}
-----------------------------------------------------------------------
whenever i wish to start the camera thread, i must first make sure the wm thread first release its handle to web cam. hence, i used to call StartCamera.
public void StartCamera()
{
if(WMThread != null)
{
if(WMThread.IsAlive)
{
StopWM();
}
}
if(cameraThread != null)
{
if(cameraThread.IsAlive)
{
StopCamera();
}
}
cameraThread = new Thread(new ThreadStart(_StartCamera));
cameraThread.Priority = ThreadPriority.Lowest;
cameraThread.Start();
}
-----------------------------------------------------------------------
inside _StartCamera, i will construct a camera COM object and capture image using that COM object. however, the COM object unable the use the web cam device whenever it wants to grap image 
i suspect that the web cam is still hold by encoder. how can i make sure web cam is released by encoder after i call Encoder.Stop()?
thank you.
regards
yccheok
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i had build a light weighted http server and recently realize that there is some bugs inside.
in my constructor, i initialize the TcpListener and the thread for receiving incoming request as follow:
----------------------------------
myListener = new TcpListener(port);
myListener.Start();
//start the thread which calls the method 'StartListen'
myThread = new Thread(new ThreadStart(StartListen));
myThread.Start() ;
----------------------------------
in my StartListen
----------------------------------
while(isRunnable)
{
//Accept a new connection
Socket mySocket = myListener.AcceptSocket() ;
if(mySocket.Connected)
{
//make a byte array and receive data from the client
Byte[] bReceive = new Byte[1024] ;
int i = mySocket.Receive(bReceive,bReceive.Length,0); //BUGS??
// rest of the code goes here
----------------------------------
sometimes, when i use a web broswer making an HTTP/GET request, my web broswer takes 5 minutes to download the contents from the computer that run light weighted server(LWS) and still get no responde. it seems that it can establish a TCP/IP connection to the LWS but get no response from the LWS.
finally, i realize that LWS will halt at the line.
-----------------------------------
int i = mySocket.Receive(bReceive,bReceive.Length,0); //BUGS??
-----------------------------------
this happen "sometimes". where "sometimes" LWS works fine and "sometimes" LWS dont :P
can anyone point me out how can i solve this problem? thank you in advance.
regards
yccheok
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hi, all
How to invoke DLL in C#?
thanks very much
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This column should help:
http://msdn.microsoft.com/library/default.asp?url=/library/en-us/dncscol/html/csharp09192002.asp
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I'm having a problem double buffering my form. I use
<br />
SetStyle(ControlStyles.UserPaint, true); <br />
SetStyle(ControlStyles.AllPaintingInWmPaint, true);<br />
SetStyle(ControlStyles.DoubleBuffer, true);<br />
and the last line gives me a System.ArgumentException. The additional info is Invalid argument used... I checked out the MSDN and it says to use them like this. They are inside the Form() constructor. Anybody have any clue why this is happening?
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public Form1()
{<font color="green">
<code>InitializeComponent();</code>
<font color="green">
<code>SetStyle(ControlStyles.UserPaint, true);
SetStyle(ControlStyles.AllPaintingInWmPaint, true);
SetStyle(ControlStyles.DoubleBuffer, true);</code>
}
This code itself does not cause a compile time error, as I placed the code inside a blank application itself and it compiles fine, you may have other issues inside your constructor.
Nick Parker
Not everything that can be counted counts, and not everything that counts can be counted. - Albert Einstein
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I figured it out  I was looping the call to the OnPaint() and inside I used a graphics object. I mistakenly Dispose()'ed of the PaintEvenArg instead of the graphics object.. I guess it doesn't like that because I took the call to Dispose() out and it works fine now
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You have to do it like this:
SetStyle(ControlStyles.UserPaint | ControlStyles.AllPaintingInWmPaint | ControlStyles.DoubleBuffer, true);
Each successive call to SetStyle eleminates the previous setting and changes it to the new one. So, essentially, your just calling SetStyle(ControlStyles.DoubleBuffer). Because double buffering has to be used in conjunction with UserPaint and AllPaintingInWmPaint, you get the error Invalid Argument Used. Using a bitwise or, you combine the values of all three into one setting.
Hope this helps.
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Hi!
I'm looking for some samples how to write an IRC client in C#.
Have someone any samples?
thx!
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Hi,
I've have a tree view control that displays a scene graph (a collection of polygons, materials etc). I would like each type of object to have it's own context menu, for example, if the user right clicks on a node, it should check the 'Tag' property of the node, and if it is of a certain type it should show a certain context menu. Do I have to create a class derived from TreeView for this, or can I do it another way?
Dave Kerr
focus_business@hotmail.com
www.focus.esmartweb.com
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Heck, I'm still trying to set up the djgpp thingy so I can do the "hello world " thing.
A lot of basic and a bit of pascal. None of which works in windows.
I need a plotter driver to run a home made plotter. It's a simple one run from the
printer port. Nothing fancy at all. A lot of other "hobby" folks would like to get it too.
I woulldn't mind trying to write it myself as a excuse to learn more about C.
Anybody interested in helping?
I made the interface boards and they work fine in dos mode with,yeck, basic.
Steppers are 400 steps per rotation 119 in.oz.
No, I don't realy expect anybody to come up for air on this.
Thanks anyway.
GaryR
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I would start simpl (Hello World), then work your way up to the Plotter Driver. When you have questions, this is a good place to post your problems. Have fun!
Joan
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Thanks Joan for the fast reply. Simple is the key word for sure.
It toke for ever to find the most basic starting level info on working with the printer and con ports.
For others that read this looking for the same. A lot of surplus electroics places have a book,
Controling the World with Your PC by Paul Burgsman. It costs like $35 and is well worth it. It has a disc
with excutables as well as hard copy in basic,pascal, and c. This is in dos mode not windows.
I want to take it into windows. No, I don't have VB, only wish I did.
Between the book and this forum, I don't expect many problems. The chore will be getting it into a GUI
so somebody other than myself can easly use it. I'm thinking cheap shareware or freeware.
At the moment the most popular method is to use the hp7475a driver and plott to file, them use a dos
program to print the plt file on the homemade plotter through the paralle (printer) port.
The mechanics and electronics were easy, that I have a degree in. Programing for windows
will be........interesting.
GaryR
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How to create an image list from a resoruce biutmap.
It's along the lines Bitmap.FromResource, and Imagelist.Images.AddStrip, but I'm lacking some syntax here.
Also, I can add a "resource template" to the project, but the "Resource View" tab remains empty. What's that?
If I could find a souvenir / just to prove the world was here [sighist]
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Here is one way to do it. First, make sure your image resource is marked as "Embedded Resource".
Assembly thisAssembly = Assembly.GetAssembly(Type.GetType("Sample.Namespace.SomeForm"));
Stream bmpStream = thisAssembly.GetManifestResourceStream(Sample.Namespace.ResourceName");
Bitmap bmp = new Bitmap(bmpStream);
ImageList.Images.AddString(bmp);
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Hi,
I've been having loads of problems with collections in C#. Up to now, my main class in my program has stored large amounts of data (vertices, polygons etc) in ArrayList's. I'd like to be able to use the Collection Editor from the properties window though, and to do that I realise I need a specific collection for each object. However, I've tried deriving from CollectionBase, and half the function's I've used with ArrayList don't work, then I tried deriving from ArrayList and the program crashed.
I'd really like to just derive from ArrayList and make the collection type specific, can I do this? Or do I have to derive from CollectionBase, and if so, what code must I implement to make it work like ArrayList? I know where to go from there, using custom collection editors, but first I need my custom collection!
Any Ideas?
Dave Kerr
focus_business@hotmail.com
www.focus.esmartweb.com
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