How to extend a listbox in VC++ - visual-studio-2010

Question

I tried to extend a listbox by adding a couple functions. I get an error ( error C2144: syntax error : 'Extended_ListBox' should be preceded by ':'). Would anyone please teach me how to fix it? I went to the line which VC++ said there was the error, but I had no clue why the constructor had an error.
using namespace System;
using namespace System::ComponentModel;
using namespace System::Collections;
using namespace System::Windows::Forms;
using namespace System::Data;
using namespace System::Drawing;
using namespace System::Collections;
using namespace System::Collections::Generic;
#include <stdio.h>
#include <stdlib.h>
#using <mscorlib.dll>
public ref class Extended_ListBox: public ListBox{
public Extended_ListBox(array<String ^> ^ textLineArray, int counter){
textLineArray_store = gcnew array<String ^>(counter);
for (int i=0; i<counter; i++){
this->Items->Add(textLineArray[i]);
textLineArray_store[i] = textLineArray[i];
}
this->FormattingEnabled = true;
this->Size = System::Drawing::Size(380, 225);
this->TabIndex = 0;
this->SelectedIndexChanged += gcnew System::EventHandler(this, &Extended_ListBox::listBox1_SelectedIndexChanged);
}
public Extended_ListBox(){
this->FormattingEnabled = true;
this->Size = System::Drawing::Size(380, 225);
this->TabIndex = 0;
this->SelectedIndexChanged += gcnew System::EventHandler(this, &Extended_ListBox::listBox1_SelectedIndexChanged);
}
private: System::Void listBox1_SelectedIndexChanged(System::Object^ sender, System::EventArgs^ e) {
int index=this->SelectedIndex;
tempstring = textLineArray_store[index];
}
private: array<String ^> ^ textLineArray_store;
private: String ^tempstring;
public: String ^GetSelectedString(){
return tempstring;
}
public: void ListBox_Update(array <String ^> ^ textLineArray, int counter){
textLineArray_store = gcnew array<String ^>(counter);
for (int i=0; i<counter; i++){
this->Items->Add(textLineArray[i]);
textLineArray_store[i] = textLineArray[i];
}
}
};

Answer 1

In C++/CLI, you specify the access modifier (public, private, etc.) differently than in, say, C# or Java.
Instead, you just write one line (note the colon, which is required):
public:
and all the following members are public. So insert that line before your constructors and remove the public keyword before the constructors. Like that:
public ref class Extended_ListBox: public ListBox{
public:
Extended_ListBox(array<String ^> ^ textLineArray, int counter){
// constructor code
}
Extended_ListBox(){
// default constructor code
}
// other public members
// ...
private:
// private members
// ...
}
Similar to the members below the constructors in your current example, except that you don't have to explicitly restate public: or private: if the next member has the same visibility.