我的问题是:为什么变量“_random”在行为被定义为静态/非静态时发生变化?为什么随机变量的行为在定义为静态或非静态时有所不同?
==>静态定义时:_random.nextDouble()返回真正的随机值。
==> when not:_random.nextDouble()返回几乎相同的值。
class Shape
{
protected Canvas _canvas;
protected UIElement _element;
static Random _random = new Random();
public Shape(Canvas canvas)
{
_canvas = canvas;
}
public void Draw()
{
double val1 = _canvas.ActualWidth * _random.NextDouble();
double val2 = _canvas.ActualHeight * _random.NextDouble();
_element.SetValue(Canvas.LeftProperty, val1);
_element.SetValue(Canvas.TopProperty, val2);
_canvas.Children.Add(_element);
}
}
public partial class MainWindow : Window
{
public MainWindow()
{
InitializeComponent();
}
private void MainWindow_Loaded(object sender, RoutedEventArgs e)
{
Shape s1 = new Circle(MemoCanvas);
for (int i = 0; i < 100; i++)
{
Shape shape1 = new Circle(MemoCanvas);
shape1.Draw();
Shape shape2 = new Square(MemoCanvas);
shape2.Draw();
}
}
}
注意:不知何故,我无法格式化我的帖子,对不起。
问候
查看[Random ctor](https://msdn.microsoft.com/en-us/library/h343ddh9(v = vs.110).aspx)页面上的注释:*默认种子值源自系统时钟并具有有限的分辨率。因此,通过对默认构造函数的调用而紧密连续创建的不同Random对象将具有相同的默认种子值,因此将产生相同的随机数集合。* – Clemens