C#扩展方法

2020-03-14 15:51:14

EKsumic

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Deconstruct这个方法可以是扩展方法。

扩展方法

① 定义一个静态类，类名随便。

② 写一个static void Deconstruct方法，并且第一个参数必须是this关键词开头。

③然后接类名+参数，接out参数。

④使用的时候，直接可以在被扩展的类的实例中点出这个扩展方法。

举例：

public class Rectangle
{
public readonly float Width;

public readonly float Height;
public Rectangle(float width, float height)
{
Width = width;
Height = height;
}
}
public static class Extensions
{
public static void Deconstruct(this Rectangle rect,out float width,out float height)
{
width = rect.Width+19;
height = rect.Height-2;
}
}
class Program
{
static void Main(string[] args)
{
var rect = new Rectangle(3, 4);
rect.Deconstruct(out var TestPara1, out var TestPara2);
Console.WriteLine(TestPara1 + " "+ TestPara2);
Console.ReadKey();
}
}

输出：

22 2

完整写法：

public class Rectangle
{
public readonly float Width;

public readonly float Height;
public Rectangle(float width, float height)
{
Width = width;
Height = height;
}
}
public static class Extensions
{
public static void Deconstruct(this Rectangle rect,out float width,out float height)
{
width = rect.Width+19;
height = rect.Height-2;
}
}
class Program
{
static void Main(string[] args)
{
var rect = new Rectangle(3, 4);
Extensions.Deconstruct(rect,out var width,out var height);
Console.WriteLine(width + " "+ height);
Console.ReadKey();
}
}