CODEWITHSUNDEEP
visual-c++c++-cli
user1873073
user1873073

Reputation: 3670

How do you convert a string to a System::Object?

I have my string:

myFunc(std::string text) {}

and I want to convert it into a System::Object. Something like...

array<Object^>^ inArgs = gcnew array<Object^>(2);
const char* ms;         
ms = text.c_str();
inArgs[1] = *ms;

Except when I try to get the string out it only gives me the first character.

...it doesn't have to be an std::string. a string of any type will do. im doing a cross thread update and trying to pass a string.

Upvotes: 0

Views: 3065

Answers (2)

Hans Passant
Hans Passant

Reputation: 942177

System::String has a constructor that accepts a const char*. You don't sound picky about the proper code page conversion so it will probably be fine:

  std::string test("hello world");
  auto managed = gcnew String(test.c_str());
  Console::WriteLine(managed);

Upvotes: 3

user1873073
user1873073

Reputation: 3670

This code is probably far from the right way. I just emulated what I do in C# for cross thread updates. The actual answer came from the comments.

init form, setup delegates, start the second thread:

public ref class Form_1 : public System::Windows::Forms::Form
{
    public:
        CL* c;
        delegate System::Void CrossThreadUpdate(Object^ obj);
        CrossThreadUpdate^ crossThreadUpdate;
        void update(Object^ obj);
        Thread^ t;
        void updateTextArea(String^ text);
        void initCL();

        Form_1(void)
        {
            InitializeComponent();
            crossThreadUpdate = gcnew CrossThreadUpdate(this, &Form_1::update);
            t = gcnew Thread(gcnew ThreadStart(this, &Form_1::initCL));
            t->Start();
            //
            //TODO: Add the constructor code here
            //
        }

thread does its thing and then lets us know its done

void Form_1::initCL() 
{
    c = new CL();
    updateTextArea("CL READY");
}

update the form 

void Form_1::update(Object^ obj) {
        array<Object^>^ arr = (array<Object^>^)obj;
        int^ op = safe_cast<int^>(arr[0]);

        switch(*op)
        {
            case 1:
                String^ text = safe_cast<String^>(arr[1]);
                wstring stringConvert = L"";
                MarshalString(text, stringConvert);
                wcout << stringConvert << endl;
                this->textBox1->Text += text + "\r\n";
                break;
        }
    }

    void Form_1::updateTextArea(String^ text) {
        array<Object^>^ args = gcnew array<Object^>(1);
        array<Object^>^ inArgs = gcnew array<Object^>(2);
        inArgs[0] = 1;
        inArgs[1] = text;
        args[0] = inArgs;
        this->Invoke(crossThreadUpdate, args);
    }

Upvotes: 0

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