Re: how to use dll(mfc) in web service - C# Discussion Boards

how to use dll(mfc) in web service

24-Feb-04 4:22

Besides what Mark said, you don't want your controls static. You actually attempted to fix the original problem in exactly the opposite way that the compiler error implied. You shouldn't make your instance members static, but make your instance qualifier for your static method a Type like Mark said.

Trying to add static controls to a form won't work. With some careful handling, you might be able to get it to work for one form, but additional instances of the form will throw exceptions or even kill your app because window handles (which back the controls in Windows Forms) cannot be shared by parent windows.

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wangxuefeng23-Feb-04 14:51

23-Feb-04 14:51

I create a mfc dll and there is an export function DoOCR(LPCTSTR infile,LPCTSTR outfile , LPCTSTR libpath).
infile and outfile is the path of input file and output file .
Now , I wanna use this dll in C# web service.
I am a beginner of c# and web service .how should i do ?
thank you!

Heath Stewart24-Feb-04 4:19

24-Feb-04 4:19

Languages targeting the CLR (i.e., ".NET Languages" like C#) can P/Invoke native functions (so this isn't web service-specific, to note).

For more information on P/Invoking native functions, see Consuming Unmanaged DLL Functions[^] in the .NET Framework SDK.

Your declaration would look something like this (but read the section above to understand what all this means):

[DllImport("yourmfc.dll", CharSet=CharSet.Auto)]
private static extern void DoOCR(string infile, string outfile, string libpath);

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wangxuefeng24-Feb-04 23:26

24-Feb-04 23:26

I have done it , but there is some problems.
I think it's the problem about privilege to read file and I have solve it by another method.
To my surprise , I can read some files and can't read the others . There is no difference between these files .
Can you tell me why it's so ? Thanks a lot.

Heath Stewart25-Feb-04 2:43

25-Feb-04 2:43

There's many things that could cause this. For one, ASP.NET runs as a particular user - ASPNET by default (a local account). Read more about the <processModel> section in the .NET Framework SDK. If this user doesn't have privileges to access the files in that directory (or an ACL is applied to the file itself), then they can't access it. ASP.NET does not run with administrative privileges and it'd be EXTREMELY stupid to do so, as it opens many possible exploits.

It could also be code access security, a feature of the CLR that grants permissions to an application based on evidence. There is more information on this in the .NET Framework SDK as well.

In either or none of these cases, the exception message - even a Win32 result code - should tell you what the problem is. If you don't see an exception in your page, look at the /trace.axd file (the log viewer in the root of your web application) if tracing is enabled.

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wangxuefeng25-Feb-04 13:36

25-Feb-04 13:36

thank you very much . I will try it right away.

wangxuefeng24-Feb-04 21:43

24-Feb-04 21:43

file processing

Rob Tomson23-Feb-04 12:47

Rob Tomson

23-Feb-04 12:47

i have an array of strings that represent filenames with the path. i want to find the last directory that is common between all the files.
ex:
c:\dir1\dir2\abc\abcd\file.ext
c:\dir1\dir2\abc\efgh\file.ext
c:\dir1\dir2\abc\efgh\123\file.ext
the last common directory would be c:\dir1\dir2\abc\

what would be the easiest way to go about this?

thanks,
Rob Tomson

--
There are 10 kinds of people. Those who understand binary and those who don't.

je_gonzalez23-Feb-04 15:27

je_gonzalez

23-Feb-04 15:27

The easiest way would be to post your question and have some write the code for you.

Here is the code:

private string FindSame(params string[] values)
{
// Default to nothing
string sAns = null;

// Start out before any valid value
int iSame = -1;

// Do we have any strings?
if (values.Length > 0)
{
// Setup for looping
bool bLoop = true;

// Holding area
char cChecking = ' ';
// Flag
bool bCheckingValid;

// Loop
while (bLoop)
{
// Move on to next character
iSame++;
// Reset flag
bCheckingValid = false;
//Loop thru the strings
for (int iValue = values.GetLowerBound(0); iValue <= values.GetUpperBound(0); iValue++)
{
// Reached the end?
if (iValue >= values[iValue].Length)
{
// No more soup for you
bLoop = false;
}
else
{
// Do we have something to compare against?
if (!bCheckingValid)
{
// Pick up comparison
cChecking = values[iValue][iSame];
// Flag that we got a value
bCheckingValid = true;
}
else
{
// Compare to string
if (cChecking != values[iValue][iSame])
{
// Mismatch!
bLoop = false;
}
}
}
}
}

// Get the string
sAns = values[values.GetLowerBound(0)].Substring(0, iSame);
}

// Return
return sAns;
}

and here is a sample call:

string sSame = this.FindSame(
@"c:\dir1\dir2\abc\abcd\file.ext",
@"c:\dir1\dir2\abc\efgh\file.ext",
@"c:\dir1\dir2\abc\efgh\123\file.ext");

Heath Stewart24-Feb-04 4:14

24-Feb-04 4:14

There are a few ways to better the performance, but that's an exercise for the original poster.

I just wanted to add that you should either use Char.ToLower before comparing, or something similar. Currently, the code won't recognize the following case (and similar cases): @"c:\dir1\file1.ext" and @"C:\DIR1\FILE2.ext" (even one difference in case would cause this to fail). Paths in Windows are case-insensitive.

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je_gonzalez24-Feb-04 5:04

je_gonzalez

24-Feb-04 5:04

Open Reply to your Private Reply:

I agree with you that a lot of people that are interested in becoming a programmer (and even many that "are") do noy belong in this field.

Like in any field, you need the drive to look for answers yourself and to read the manual (how old is RTFM now?) and to dig in deeper, and too many are plain too lazy to do so.

However, I have met many who do have the drive, and the ability is within them, they just lack that insight of thinking outside themselves, which may be (AND IT IS A BIG MAY BE) triggered by seeing a piece of code.

I do not know about you, you may have all the answers and need help from no one, but I have gotten great ideas from reading thru some of these boards (the latest example is the work by Tom Clements on menus here at CP, which gave me insight on how to solve a nasty problem I was facing), and provide the little assistance I humbly do to pay back into the system.

Once before I answered someone and it seemed to cause some problem with you, and I apologized, even when I felt that I had done nothing wrong. This time you are telling me not to help people out, and to that my answer is to go play with yourself. I do not believe that this board belongs to you, and if it does, publicly tell everyone so and I will happily go someplace else.

Rob Tomson24-Feb-04 17:45

Rob Tomson

24-Feb-04 17:45

Thank you very much. Sorry it took so long to reply but anyway...I took your basic idea and massaged it abit and came up with this:

<br />
private int FindCommonDirectory(string[] files)<br />
{<br />
	string path = "";<br />
	foreach (string file in files)<br />
	{<br />
		string filePath = file.Substring(0, file.LastIndexOf(dirSep) + 1);<br />
		if ("" == path) path = filePath;<br />
		else if (filePath == path){}<br />
		else if (!filePath.StartsWith(path))<br />
		{<br />
			for (int chr = 0; chr <= filePath.Length; chr++)<br />
			{<br />
				if (filePath[chr] != path[chr])<br />
				{<br />
					path = filePath.Substring(0, chr);<br />
					break;<br />
				}<br />
			}<br />
		}<br />
	}<br />
	return path.LastIndexOf(dirSep);<br />
}<br />

Basically what it does is gets the directory of the first item and then compares it to the rest of the items, char by char. Every time it finds a shorter directory it then uses that to compare with the rest.

Thanks again for your help,
Rob

--
There are 10 kinds of people. Those who understand binary and those who don't.

Re: how to clear a combobox?

je_gonzalez24-Feb-04 19:40

je_gonzalez

24-Feb-04 19:40

You're welcome. The idea was to give an example, and let you run with it.

Next, pass it forward, when you see a question that you have an answer for, give them a hand.

how to clear a combobox?

Anonymous23-Feb-04 11:56

Anonymous

23-Feb-04 11:56

hello

can anyone tell me how to clear
or reset to the default value of the
combo box in winforms?

Werdna23-Feb-04 14:27

Werdna

23-Feb-04 14:27

I'm not sure if you want to delete all items, or just reset the text.
To delete all items you do:
combobox.Items.Clear()
to set a value displayed:
combobox.Text = "text value";

How to get number of running threads?

CWIZO23-Feb-04 11:32

CWIZO

23-Feb-04 11:32

Hi,

how can I get the number of running threads on the machine. Not just the ones I have created but all threads.
I have googeled a little but didn't find anything useful ...

Q:What does the derived class in C# tell to it's parent?
A:All your base are belong to us!

Re: How to get number of running threads?

Heath Stewart24-Feb-04 4:03