. Operator (C# Reference) 

The dot operator (.) is used for member access. The dot operator specifies a member of a type or namespace. For example, the dot operator is used to access specific methods within the .NET Framework class libraries:

// The class Console in namespace System:
System.Console.WriteLine("hello"); 

Remarks

For example, consider the following class:

class Simple 
{
    public int a;
    public void b()
    {
    }
}
Simple s = new Simple();

The variable s has two members, a and b; to access them, use the dot operator:

s.a = 6;   // assign to field a;
s.b();     // invoke member function b;

The dot is also used to form qualified names, which are names that specify the namespace or interface, for example, to which they belong.

// The class Console in namespace System:
System.Console.WriteLine("hello");

The using directive makes some name qualification optional:

using System;
// ...
System.Console.WriteLine("hello");
Console.WriteLine("hello");   // same thing

But when an identifier is ambiguous, it must be qualified:

using System;
// A namespace containing another Console class:
using OtherSystem; 
// ...
// Must qualify Console: 
System.Console.WriteLine( "hello" );

C# Language Specification

For more information, see the following sections in the C# Language Specification:

• 7.5.4 member access

See Also

Reference

C# Operators

Concepts

C# Programming Guide

Other Resources

C# Reference