Csharp/CSharp Tutorial/2D/Mouse Draw

Basic Paint Form: click mouse button to add the an Ellipse

<source lang="csharp">using System; using System.Drawing; using System.Collections; using System.ruponentModel; using System.Windows.Forms; using System.Data; using System.Drawing.Drawing2D; public class FormBasicPaintMouseClick : System.Windows.Forms.Form {

 private System.ruponentModel.Container components = null;
 private System.Windows.Forms.Button btnRenderedButton;
 private System.Windows.Forms.Button btnRenderToOtherButton;
 private ArrayList myPts = new ArrayList();
 public FormBasicPaintMouseClick()
 {
   InitializeComponent();
 }
 protected override void Dispose( bool disposing )
 {
   if( disposing )
   {
     if (components != null) 
     {
       components.Dispose();
     }
   }
   base.Dispose( disposing );
 }
 private void InitializeComponent()
 {
   this.btnRenderedButton = new System.Windows.Forms.Button();
   this.btnRenderToOtherButton = new System.Windows.Forms.Button();
   this.SuspendLayout();
   // 
   // btnRenderedButton
   // 
   this.btnRenderedButton.Location = new System.Drawing.Point(168, 120);
   this.btnRenderedButton.Name = "btnRenderedButton";
   this.btnRenderedButton.Size = new System.Drawing.Size(112, 136);
   this.btnRenderedButton.TabIndex = 0;
   this.btnRenderedButton.Text = "Click on other button!";
   // 
   // btnRenderToOtherButton
   // 
   this.btnRenderToOtherButton.Location = new System.Drawing.Point(168, 8);
   this.btnRenderToOtherButton.Name = "btnRenderToOtherButton";
   this.btnRenderToOtherButton.Size = new System.Drawing.Size(112, 56);
   this.btnRenderToOtherButton.TabIndex = 1;
   this.btnRenderToOtherButton.Text = "Render to button";
   // 
   // FormBasicPaintMouseClick
   // 
   this.AutoScaleBaseSize = new System.Drawing.Size(5, 13);
   this.ClientSize = new System.Drawing.Size(292, 273);
   this.Controls.Add(this.btnRenderToOtherButton);
   this.Controls.Add(this.btnRenderedButton);
   this.Name = "FormBasicPaintMouseClick";
   this.StartPosition = System.Windows.Forms.FormStartPosition.CenterScreen;
   this.Text = "Basic Paint Form";
   this.MouseDown += new System.Windows.Forms.MouseEventHandler(this.FormBasicPaintMouseClick_MouseDown);
   this.Paint += new System.Windows.Forms.PaintEventHandler(this.FormBasicPaintMouseClick_Paint);
   this.ResumeLayout(false);
 }
 [STAThread]
 static void Main() 
 {
   Application.Run(new FormBasicPaintMouseClick());
 }
 private void FormBasicPaintMouseClick_MouseDown(object sender, System.Windows.Forms.MouseEventArgs e)
 {
   myPts.Add(new Point(e.X, e.Y));
   Invalidate();
 }
 private void FormBasicPaintMouseClick_Paint(object sender, System.Windows.Forms.PaintEventArgs e)
 {
   Graphics g = e.Graphics;
   foreach(Point p in myPts)
     g.DrawEllipse(new Pen(Color.Green), p.X, p.Y, 10, 10);
 }

}</source>