Convert a 'System::String ^' to 'const char *' in vc++

问题:

How can I convert a 'System::String ^' to 'const char *' in vc++?

My code:

String ^Result1= "C:/Users/Dev/Desktop/imag.jpg";

IplImage *img1 = cvLoadImage(Result1, 1);

if I do like above it will generate following error.

error C2664: 'cvLoadImage' : cannot convert parameter 1 from 'System::String ^' to 'const char *'

Please help me.

回答1:

It's like this: How to convert from System::String* to Char* in Visual C++

System::String ^ str = "Hello world\n";  //method 1 pin_ptr<const wchar_t> str1 = PtrToStringChars(str); wprintf(str1);    //method 2 char* str2 = (char*)Marshal::StringToHGlobalAnsi(str).ToPointer(); printf(str2); Marshal::FreeHGlobal((IntPtr)str2);  //method 3 CString str3(str);  wprintf(str3);  //method 4 #if _MSC_VER > 1499 // Visual C++ 2008 only marshal_context ^ context = gcnew marshal_context(); const char* str4 = context->marshal_as<const char*>(str); puts(str4); delete context; #endif 

回答2:

This is work for me.

void MarshalString ( String ^ s, string& os ) {     using namespace Runtime::InteropServices;     const char* chars =        (const char*)(Marshal::StringToHGlobalAnsi(s)).ToPointer();     os = chars;     Marshal::FreeHGlobal(IntPtr((void*)chars)); } 

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