Part 3: Initialising objects

Consider the following simple class definition:

//Simple client class used to demonstate //C#3 object initialisation class Client {     //Read-write property for the client's name     public string Name { get; set; }     //Read-write property for the client's age     public int Age { get; set; }     //Read-write property for the client's height     public double Height { get; set; }     //Read only property that is True for existing     //clients and False for new clients     public bool IsCurrent { get; private set; } }

A constructor has not been explicitly created for this class so the compiler will generate a default, parameterless one for us. This means that an object can be created and properties assigned inthe way that we are currently used to with C#2

//Create a client object using the default constructor Client firstClient = new Client(); //Assign values to the class properties that have public set methods firstClient.Name = "David"; firstClient.Age = 32; firstClient.Height = 124;

However, with C#3, we are now able to create an object using any of the following methods:

//Construct the object by supplying the client Name Client secondClient =     new Client { Name = "Matthew" }; //Construct the object by supplying //the client Name & Age Client thirdClient =      new Client { Name = "Sarah", Age = 21 }; //Construct the object by supplying //the client Name & Height Client fourthClient =     new Client { Name = "Daniel", Height = 131 }; //Construct the object by supplying //the client Height only Client fifthClient = new Client { Height = 108 };

This is essentially identical to creating a client object with the default constructor and then calling each property set method as appropriate. Looking at the disassembled code shows us what isactually happening for these client objects.

Client <>g__initLocal0 = new Client(); <>g__initLocal0.Name = "Matthew"; Client secondClient = <>g__initLocal0; Client <>g__initLocal1 = new Client(); <>g__initLocal1.Name = "Sarah"; <>g__initLocal1.Age = 0x15; Client thirdClient =<>g__initLocal1; Client <>g__initLocal2 = new Client(); <>g__initLocal2.Name = "Daniel"; <>g__initLocal2.Height = 131.0; Client fourthClient = <>g__initLocal2; Client <>g__initLocal3 = new Client(); <>g__initLocal3.Height = 108.0; Client fifthClient = <>g__initLocal3;

As the code above shows, each client is constructed using the default constructor and then the property set methods are called as necessary. Of course, we cannot specify a value for IsCurrent when creating a client object because the set property is marked private (as shown in the first code snippet). Trying to do so will generate a compile time error of something like: The property orindexer ‘Blog.Client.IsCurrent’ cannot be used in this context because the set accessor is inaccessible.

Part 4: Implicit types