.NET Framework Object.ToString() virtual method


Example

Everything in .NET is an object, hence every type has ToString() method defined in Object class which can be overridden. Default implementation of this method just returns the name of the type:

public class Foo
{
}

var foo = new Foo();
Console.WriteLine(foo); // outputs Foo

ToString() is implicitly called when concatinating value with a string:

public class Foo
{
    public override string ToString()
    {
        return "I am Foo";
    }
}

var foo = new Foo();
Console.WriteLine("I am bar and "+foo);// outputs I am bar and I am Foo

The result of this method is also extensively used by debugging tools. If, for some reason, you do not want to override this method, but want to customize how debugger shows the value of your type, use DebuggerDisplay Attribute (MSDN):

// [DebuggerDisplay("Person = FN {FirstName}, LN {LastName}")]
[DebuggerDisplay("Person = FN {"+nameof(Person.FirstName)+"}, LN {"+nameof(Person.LastName)+"}")]
public class Person
{
    public string FirstName { get; set; }
    public string LastName { get; set;}
    // ...
}