A class can be defined over multiple source files. All of the source files are combined into one class when the application is compiled.

• It is declared using the partial keyword.
• All of the source files must use the partial keyword.
• All the files must have the same access modifier, e.g. public, private, etc.
• If any file is declared abstract, the whole class becomes abstract.

Example

namespace MyConsoleApp
{
    public partial class Student
    {
        public void AttendClass()
        { 
        }
    }

    public partial class Student
    {
        public void DoHomework()
        {
        }
    }
}