1. What are the ways to initialize objects?
2. What are the ways to initialize nested members?
3. What are the ways to initialize lists and arrays?
Example 1:
public class Test
{
public Test() { }
public Test(bool param1, int param2)
{
Property1 = param1;
Property2 = param2;
}
public bool Property1 { set; get; }
public int Property2 { set; get; }
public string Property3 { set; get; }
public override string ToString()
{
return Property1.ToString() + Property2.ToString() + Property3;
}
}
class Program
{
static void Main(string[] args)
{
var test = new Test { Property1 = true, Property2 = 3 };
var test2 = new Test(false, 1) { Property3 = "Test" };
}
}
In first case the default constructor is called and properties are initilized by specified values. In second case the specific construcor is called and property is initilized by a value.
Example 2:
public class Point
{
public int X { set; get; }
public int Y { set; get; }
}
public class Rectangle
{
public Point TopLeft { set; get; }
public Point BottomRight { set; get; }
}
var rect = new Rectangle { TopLeft = new Point { X = 0, Y = 0 }, BottomRight = new Point() { X = 10, Y = 10 } };
It is possible to initialize nested members using object initialization expressions.
Example 3:
public class Rectangle
{
Point topLeft = new Point { X = 0, Y = 0 };
Point bottomRight = new Point { X = 10, Y = 10 };
public Point TopLeft { set { topLeft = value; } get { return topLeft; } }
public Point BottomRight { set { bottomRight = value; } get { return bottomRight; } }
}
var rect = new Rectangle { TopLeft = { X = 0, Y = 0 }, BottomRight = { X = 10, Y = 10 } };
In case of nested members are already initialized we can skip the new operator.
Example 4:
static void Main(string[] args)
{
List<int> integers = new List<int> { 1, 3, 9, 18 };
List<Test> list = new List<Test>{
new Test(){ Property2 = 0 },
new Test(){ Property2 = 1 },
new Test(){ Property2 = 2 }
};
Trace.WriteLine("———————————–");
ArrayList arrayListOfInts = new ArrayList() { 1, 3, 9, 18 };
ArrayList arrayListOfTests = new ArrayList()
{
new Test(){ Property2 = 0 },
new Test(){ Property2 = 1 },
new Test(){ Property2 = 2 }
};
list.ForEach(el => Trace.WriteLine(el));
foreach (var el in arrayListOfTests)
{
Trace.WriteLine(el);
}
}
As we can add constants to lists and arrays, we can add initialized objects there by using object initialization expressions.
Grigory's space 