Question

I am calling function of the same class from constructor. But its giving me the error.

public class Connection
{
    public Connection()
    {
    }

    public Connection(string parameter) : this(GetConnection(parameter))
    {
    }

    private static string GetConnection(string parameter)
    {
        return parameter;
    }
}

But public Connection(string parameter) : this(GetConnection(parameter)) is giving me error.
The error is:

Constructor ‘Test.Connection.Connection(string)’ cannot call itself.

What is the error behind this. Is this type of calling possible??

Thanks!!!

`

Answer 1

You can call another constructor with this syntax (either this class constructor through this keyword, or one of the available base class constructors through base keyword). While you’re having a potential StackOverflowException here instead.

You can simply do this:

public class Connection
{
    public Connection()
    {
    }

    public Connection(string parameter)
        : this()
    {
        string connectionString = GetConnection(parameter);
    }
}

---

Off topic: the following potential StackOverflowException is already not identifiable by compiler (i.e. it’s compiled without errors and warnings), but only at runtime:

public class Connection
{
    public Connection()
        : this(GetConnectionString())
    {
    }

    public Connection(string parameter)
        : this()
    {
    }

    public static string GetConnectionString()
    {
        //...
    }
}

Please read Using Constructors (C# Programming Guide) for more info:

A constructor can invoke another constructor in the same object using
the this keyword. Like base, this can be used with or without
parameters, and any parameters in the constructor are available as
parameters to this, or as part of an expression.

Also see Calling base constructor in c#.