char* to a string in C#

Question

I\'m calling a function from a native DLL which returns a char* pointer, how can I convert the returned pointer to a string ? I tried :

char* c = f         


        

Answer 1

public static void Main(string[] args)
        {
            var charArray = new[] {'t', 'e', 's', 't'};
            fixed (char* charPointer = charArray)
            {
                var charString = new string(charPointer);
            }
        }

Answer 2

Your example isn't completely clear, but your comment suggests you're calling into a c++ dll from c#. You need to return a bstr, not a char * or a string.

I'd start with this question/answer, which I used when I had to perform this operation:

How to return text from Native (C++) code

Answer 3

Update your P/Invoke declaration of your external function as such:

[DllImport ( "MyDll.dll", CharSet = CharSet.Ansi, EntryPoint = "Func" )]
[return : MarshalAs( UnmanagedType.LPStr )]
string Func ( ... );

This way you won't have to do extra work after you get the pointer.

Answer 4

Perhaps the native DLL is actually returning an ANSI string instead of a Unicode string. In that case, call Marshal.PtrToStringAnsi:

using System.Runtime.InteropServices;
...
string s = Marshal.PtrToStringAnsi((IntPtr)c);