Inherited class needs parameter for base class constructor

Question

I made 2 managed classes in C++ clr, and I have a constructor on the base class. The derived class is inheriting from the base one, and I believe that since my constructor on the parent class has parameters not equal to void, that when I call it to be inherited it needs a parameter for the constructor. I believe this because when I stop inheriting, the error goes away. I can't just put (parameter) after inheriting it, so my question is how do I get it to be inherited without asking for a parameter for the constructor.

Here is my full error:

Severity    Code    Description Project File    Line    Suppression State
Error   C2512   'ConnectDB': no appropriate default constructor available   Credit Card Storage System  C:\Users\dehla\Desktop\Visual Studio Projects\C++\Credit Card Validator\Query.h 26  

Here is my Header File:

#ifndef DATA_BASE
#define DATA_BASE

using namespace System;
using namespace System::Data::SqlClient;

ref class ConnectDB{
protected:
    SqlConnection^ cnn;
    String^ sql_file;
    bool state;

public:
    ConnectDB(System::String^ in_file);
    bool ConnectDataBase();
    ~ConnectDB(void);
};

ref class Query : public ConnectDB{
private:
public:
    
};

#endif 

Here is my cpp file:

#include "Query.h"

ConnectDB::ConnectDB(System::String^ in_file){
    sql_file = System::IO::File::ReadAllText(in_file);
}

bool ConnectDB::ConnectDataBase() {
    String^ connectionString = "Data Source=WIN-50GP30FGO75;Initial Catalog=Demodb;User ID=sa;Password=demol23";
    SqlConnection^ cnn = gcnew SqlConnection(connectionString);
    cnn->Open();

    state = true;
    return true;
}

ConnectDB::~ConnectDB() {
    cnn->Close();
}

Answer 1

Your subclass doesn't need a constructor with arguments, but all constructors need to call the base class constructor properly.

As the base class doesn't have a default constructor, you need to do something like this:

class Query : public ConnectDB{
private:
public:
    Query(): ConnectDB("") { ... }
    
};

The thing is, unless you want to hardcode the value input to ConnectDB, your base class probably needs a constructor with a string parameter so you can forward it to ConnectDB's constructor.