Classes in c# with constructor

Question

What does the end of the header mean?

MobilePhone(string phoneNumber, string name) : this(phoneNumber)
{
    this.name = name;
}

Answer 1

: this(phoneNumber) invokes another constructor overload that only accepts a phone number (or at least a string):

MobilePhone(string phoneNumber, string name) : this(phoneNumber)
{
    this.name = name;
}

//this one is invoked using 'this(phoneNumber)' above
MobilePhone(string phoneNumber)
{
    this.phoneNumber = name;
}

Answer 2

I guess you are referring to the : this(phoneNumber).

This is basically a second constructor call. It is called constructor chaining.

You basically have two constructors and one calls the second one for its contents.

//Constructor A gets called and calls constructor B
MobilePhone(string number, string name) : this(number) 
{
    this.name = name;
}

//This would be constructor B
MobilePhone(string number)
{
    this.number = number;
}

Answer 3

this(phoneNumber)

means 'before you call the below code, call the other MobilePhone constructor (which takes a single string parameter), passing in phoneNumber as the parameter to it'.