MT4 build 600+ C# and DLL Strings
OK, solved!
I had to add MarshalAs directives to make it work again. Just like this:
public static bool testFunction([MarshalAs(UnmanagedType.LPWStr)] string testString)
{
writeToDebugFile(testString);
return true;
}
Quite simple in fact :)
I solved a similar problem, but with string return value.
For others:
[DllExport("getLastStatus", CallingConvention = CallingConvention.StdCall)]
[return: MarshalAs(UnmanagedType.LPWStr)]
public static string getLastStatus(int ECIndex) {
// ...
return "Your string";
}
I solved a similar problem, but with string return value.
For others:
[DllExport("getLastStatus", CallingConvention = CallingConvention.StdCall)]
[return: MarshalAs(UnmanagedType.LPWStr)]
public static string getLastStatus(int ECIndex) {
// ...
return "Your string";
}
I tried this approach to returning a String using DllExport and it did not free the memory. If you're doing this every tick in Strategy Tester, you'll notice. Maybe a bug in DllExport?
Anyway, the workaround is to do the following (as per https://www.mql5.com/en/articles/249)
[DllExport("GetCommandName", CallingConvention = CallingConvention.StdCall)]
public static void GetCommandName(Int64 ix, int id, [In, Out, MarshalAs(UnmanagedType.LPWStr)] StringBuilder commandName)
And the MQL:
string name = "";
GetCommandName(ix, requestId, name);
- Free trading apps
- Over 8,000 signals for copying
- Economic news for exploring financial markets
You agree to website policy and terms of use
Hello,
Prior to build 600, I wrote a C# DLL that worked perfectly but it seems that build 600 broked my EA calls.
The C# DLL define some functions like this (using RGiesecke library):
[DllExport("loadAllDatabase", CallingConvention = CallingConvention.StdCall)]
public static bool testFunction(string testString)
{
writeToDebugFile(testString);
return true;
}
On the EA side, something like this is written:
#import "myLibrary.dll"
bool testFunction(string connectionString);
testFunction("Test string");
I understand that build 600+ now uses Unicode string instead of ANSI ones, but I have to admit that don't have a clue how to handle this. :)
Does anybody know?
Thank you!