我正在尝试使用paint方法在表单上绘制移动的矩形和圆形。一个按钮应该开始该过程。第二次按应结束程序。一旦变量是在开始时设置为True的全局布尔值。X1是全局int,在开始时设置为10。Up是一个全局布尔值,在启动时设置为true。
每次迭代时,X1变量都会不断增加,直到100,然后逐渐减少到10。
我观察到以下两个问题。
以下为代码:
private void Form1_Paint(object sender, PaintEventArgs e)
{
Pen red = new Pen(Color.Red,3);
Rectangle rect = new Rectangle(x1, x1, x1, x1);
Rectangle circle = new Rectangle(x1+10, x1 + 10, x1 + 50, x1 + 50);
//Graphics g = e.Graphics;
Graphics g = CreateGraphics();
g.DrawRectangle(red,rect);
g.DrawEllipse(red, circle);
red.Dispose();
g.Dispose();
}
private void button2_Click(object sender, EventArgs e)
{
if (once)
once = false;
else
Environment.Exit(0);
while (true)
{
if (up )
{
x1 += 10;
if (x1 > 100)
up = false;
}
else
{
x1 -= 10;
if (x1 <= 10)
up = true;
}
this.Invalidate();
Thread.Sleep(500);
}
}
这里是使用System.Windows.Forms.Timer
完成此任务的一种方法,请参见更改和注释:
private int x1 = 4;
System.Windows.Forms.Timer timer;
private bool once = true;
private bool up = false;
private void Form1_Paint(object sender, PaintEventArgs e)
{
// use e.Graphics
Graphics g = e.Graphics;
Pen red = new Pen(Color.Red, 3);
Rectangle rect = new Rectangle(x1, x1, x1, x1);
Rectangle circle = new Rectangle(x1 + 10, x1 + 10, x1 + 50, x1 + 50);
g.DrawRectangle(red, rect);
g.DrawEllipse(red, circle);
red.Dispose();
g.Dispose();
}
private void button2_Click(object sender, EventArgs e)
{
if (once)
{
once = false;
Init();
}
else
{
if (timer != null)
{
timer.Stop();
timer.Dispose();
timer = null;
}
// you can exit app...
Application.Exit();
}
}
private void Init()
{
if (timer == null)
{
timer = new Timer();
timer.Interval = 500;
timer.Tick += timer_tick;
}
timer.Start();
}
private void timer_tick(object sender, EventArgs e)
{
if (up)
{
x1 += 10;
if (x1 > 100)
up = false;
}
else
{
x1 -= 10;
if (x1 <= 10)
up = true;
}
this.Invalidate();
}