在C中拖放矩形＃

Question

我想知道如何在C＃中繪製矩形，並將其拖放到頁面中的這裏我的代碼來繪製它，但我不能拖放它。

public partial class Form1 : Form 
{ 
    public bool drag = false; 
    int cur_x, cur_y; 
    Rectangle rec = new Rectangle(10, 10, 100, 100); 
    public Form1() 
    { 
     InitializeComponent(); 
    } 

    protected override void OnPaint(PaintEventArgs r) 
    { 
     base.OnPaint(r); 
     Graphics g = r.Graphics; 
     //g.DrawRectangle(Pens.Black, rec); 
     g.FillRectangle(Brushes.Aquamarine, rec); 

    } 
    private void recmousedown(object sender, MouseEventArgs m) 
    { 
     if (m.Button != MouseButtons.Left) 
      return; 
     rec = new Rectangle(m.X, m.Y,100,100); 

     drag = true; 
     cur_x = m.X; 
     cur_y = m.Y; 
    } 

    private void recmousemove(object sender, MouseEventArgs m) 
    { 
     if (m.Button != MouseButtons.Left) 
      return; 

     rec.X = m.X; 
     rec.Y = m.Y; 
     Invalidate(); 
    } 
} 

Answer 1

你可以嘗試本文中的方法：http://beta.codeproject.com/KB/GDI-plus/flickerFreeDrawing.aspx

Answer 2

你很接近，你只需要初始化矩形更好，調整Move事件矩形大小：

public partial class Form1 : Form { 
    public Form1() { 
     InitializeComponent(); 
     this.DoubleBuffered = true; 
    } 
    Rectangle rec = new Rectangle(0, 0, 0, 0); 

    protected override void OnPaint(PaintEventArgs e) { 
     e.Graphics.FillRectangle(Brushes.Aquamarine, rec); 
    } 
    protected override void OnMouseDown(MouseEventArgs e) { 
     if (e.Button == MouseButtons.Left) { 
     rec = new Rectangle(e.X, e.Y, 0, 0); 
     Invalidate(); 
     } 
    } 
    protected override void OnMouseMove(MouseEventArgs e) { 
     if (e.Button == MouseButtons.Left) { 
     rec.Width = e.X - rec.X; 
     rec.Height = e.Y - rec.Y; 
     Invalidate(); 
     } 
    } 
    }