strings in DLL calls

[Gian]

i need to call a function of a C DLL. the function is declared as _EXTERN int __stdcall MyFunction(HWND hWndParent, LPTSTR lpszRow1, LPTSTR lpszRow2, LPTSTR lpszRow3); so i've defined in my c# code [DllImport("library.dll", CharSet=CharSet.Auto)] protected static extern Int32 MyFunction(int hWndParent, StringBuilder lpszRow1, StringBuilder lpszRow2, StringBuilder lpszRow3); in the C/C++ code i have to pass 3 strings of 42 chars (8-bit each) and the function fills the tree with some names. in c# i've created 3 StringBuilder variables and initialized to 42 of both length and max capacity. When i call the function the strings are written but the problem is that each char of the StringBuilder is of 16-bit so 2 characters are in one. Is there a way to extract each single char or to define a StringBuilder of 8-bit elements? I've tried to use string and LPTStr parameters for the function but the DLL doesnt seem to copy anything in my strings. Gianmaria

[Gian]

i've resolved changing CharSet=CharSet.Auto to CharSet=CharSet.Ansi in the function definition :)