Drag and drop rectangle in C#
I want to know how to draw rectangle in C# and make it dragged and dropped in the page here my code to draw it but I cannot drag or drop it.
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.Bu开发者_开发知识库tton != 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();
}
}
You're pretty close, you just need to initialize the rectangle better and adjust the rectangle size in the Move event:
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();
}
}
}
You could try the approach in this article: http://beta.codeproject.com/KB/GDI-plus/flickerFreeDrawing.aspx
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