Hi,
I have tried the second approach.. passing a byte[] in to my C dll(eVC).
please go thorough my code..
----------- My managed code ----------------
char[] buf = new char[bufferSize+1];
byte[] buffer = Encoding.ASCII.GetBytes(buf); // or can I just send a
byte[]. I mean
// byte[]
buffer = new byte[100].
// byte[]
result = GetString(buffer).
byte[] result = GetString(buffer); // method in my DLL.
string s = Encoding.ASCII.GetString(result,0,result.Length);
------------- My unmanaged code in C dll --------------------
char* GetString(char* buffer) // NotSupportedException is occurring here.
{
strcpy(buffer, string);
return buffer;
}
When I run this code.. I am getting "NotSupportedException" at the function
GetString. I'm not sure that how to receive byte[] in
C dll in EVC. How to resolve this problem.
My doubt is, what is a good practice for sending byte[] to C dll and how do
we can we manipulate this buffer in unmanaged code.
Where can I get detailed information about the translation between any two
string representations in .NET Compact Framework/.NET Framework.
Kindly let me know.
Cheers,
Naveen.
"Alex Feinman [MVP]" wrote:
> Well, the easiest thing to do would be using Unicode in your C++ module. As
> for conversions, there are several ways to approach this:
>
> StringBuilder sb = new StringBuilder();
> int pos = 0;
> byte ch = Marshal.ReadByte( m.LParam, pos++ );
> while( ch != 0 )
> {
> sb.Append(ch);
> ch = Marshal.ReadByte( m.LParam, pos++ );
> }
>
> Of course you will need to guarantee that the trailing zero is there - you
> cannot catch unmanaged exception from the managed code.
> Ideally, you would want to pass string length as wParam.
>
> Even better way to handle this would be to use message as the signal for the
> application to make a call into the DLL passing a byte buffer, which DLL
> will fill with the string. Then you would use Encoding.ASCII.GetString to
> convert the buffer contents to string
>
> --
> Alex Feinman
> ---
> Visit http://www.opennetcf.org
> "Naveen Mukkelli" <(E-Mail Removed)> wrote in
> message news:102455B5-B56D-45C9-87DF-(E-Mail Removed)...
> > Hi,
> >
> > I need to send a string from my DLL( in eVC 4.0)
> > to a C# application.
> >
> > I have declared the string as "char *someString".
> > for example,
> >
> > ********code in my DLL*******
> >
> > char *someString;
> > someString = (GetString)(...); // GetString is a pointer to a function in
> > a
> > // third party DLL. This
> > function returns a char *.
> >
> > SendMessage(,, (LPARAM)someString);
> >
> > ***********code in my DLL ends****************
> >
> > ######## code in my C# application########
> > unsafe
> > {
> > string str = new string((char *)m.LParam.ToPointer());
> > }
> > MessageBox.Show(str);
> >
> > ######## code in my C# application ends here ########
> >
> > in my C# application, MessageBox is
> > showing some symbols rather than the actual string. I presume that
> > the string which is sent by the DLL might be in UNICODE.
> >
> > I want to display the actual string, How can I do this.
> >
> > Kindly let me know.
> >
> > Cheers,
> >
> > Naveen.
> >
>
>
>
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