Pass C# string to eVC DLL

[devgrt]

I have an eVC DLL that I call from C#. I want to pass a C# string to the dll
and then copy that string's data into a char buffer as shown below. It
fails. Could anyone help me fix this code to what it should be. Thank you!

eVC DLL:
int mydll(LPSTR s)
{
char data[40];
strcpy(data, s);
}

C# calling the DLL:
[DllImport("MyCProcess.dll")]
public static extern int mydll(string s);
int r = mydll("teststring");

 

[Paul G. Tobey [eMVP]]

Fails how? C# strings, it should be clear, are always Unicode, not ASCII.
If you're counting on the string to consist of 8-bit characters, you're
wrong and it's probably showing you just the first character.

Paul T.

 

[Chris Tacke, MVP]

CE is unicode, so you shouldn't be using char, but instead either wchar_t or
the TCHAR macro, along with the right copy function.

-Chris

 

[jakubbukaj]

Try this:
[DllImport("MyCProcess.dll")]
public static extern int mydll([Out] StringBuilder s);