Form.Invalidate : Form « System.Windows.Forms « C# / C Sharp by API

1. C# / C Sharp by API
2. System.Windows.Forms
3. Form

Form.Invalidate

   

using System;
using System.Drawing;
using System.Windows.Forms;

public class PaintInvalidate : Form
{
  private Button btn;

  public PaintInvalidate()
  {
    Size = new Size(300,200);

    btn = new Button();
    btn.Parent = this;
    btn.Location = new Point(25,25);
    btn.Text = "Update";
    btn.Click += new System.EventHandler(btn_Click);
  }

  static void Main() 
  {
    Application.Run(new PaintInvalidate());
  }

  protected override void OnPaint(PaintEventArgs e)
  {
    base.OnPaint(e);
    Graphics g = e.Graphics;
    String str = "\nThe time is " + DateTime.Now.ToLongTimeString();
    g.DrawString(str, Font, Brushes.Black, 50, 75);
  }

  private void btn_Click(object sender, EventArgs e)
  {
    Invalidate();
  }
}

   
    
    
  

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