ScrollBar Value changed event handler : ScrollBar « GUI Windows Forms « C# / CSharp Tutorial






ScrollBar Value changed event handler
using System;
using System.Drawing;
using System.Windows.Forms;

public class ScrollBarsControlPictureBox : Form
{
  Panel pnl;
  PictureBox pb;
  HScrollBar hbar;
  VScrollBar vbar;
  Image img;

  public ScrollBarsControlPictureBox()
  {
    Size = new Size(480,300);

    img = Image.FromFile("YourFile.gif");

    pnl = new Panel();
    pnl.Parent = this;
    pnl.Size = new Size(400,200);
    pnl.Location = new Point(10,10);
    pnl.BorderStyle = BorderStyle.FixedSingle;

    pb = new PictureBox();
    pb.Parent = pnl;
    pb.Size = new Size(img.Size.Width, img.Size.Height);
    pb.Location = new Point((pnl.Size.Width / 2) - (pb.Size.Width / 2),
                (pnl.Size.Height / 2) - (pb.Size.Height / 2));
    pb.SizeMode = PictureBoxSizeMode.CenterImage;
    pb.Image = img;

    hbar = new HScrollBar();
    hbar.Parent = this;
    hbar.Location = new Point(pnl.Left, pnl.Bottom + 25);
    hbar.Size = new Size(pnl.Width, 25);
    hbar.Minimum = 0;
    hbar.Maximum = 100;
    hbar.SmallChange = 1;
    hbar.LargeChange = 10;
    hbar.Value = (hbar.Maximum - hbar.Minimum) / 2;
    hbar.ValueChanged += new EventHandler(hbar_OnValueChanged);

    vbar = new VScrollBar();
    vbar.Parent = this;
    vbar.Location = new Point(pnl.Right + 25, pnl.Top);
    vbar.Size = new Size(25, pnl.Height);
    vbar.Minimum = 0;
    vbar.Maximum = 100;
    vbar.SmallChange = 1;
    vbar.LargeChange = 10;
    vbar.Value = (vbar.Maximum - vbar.Minimum) / 2;
    vbar.ValueChanged += new EventHandler(vbar_OnValueChanged);

  }

  private void hbar_OnValueChanged(object sender, EventArgs e)
  {
    pb.Location = new Point((pnl.Size.Width - img.Size.Width) * (hbar.Value) / (hbar.Maximum - hbar.LargeChange + 1), pb.Top);
  }

  private void vbar_OnValueChanged(object sender, EventArgs e)
  {
    pb.Location = new Point(pb.Left, (pnl.Size.Height - img.Size.Height) * vbar.Value / (vbar.Maximum - vbar.LargeChange + 1));
  }

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








23.24.ScrollBar
23.24.1.Use ScrollBar to control PictureUse ScrollBar to control Picture
23.24.2.ScrollBar Value changed event handlerScrollBar Value changed event handler
23.24.3.ScrollBar Large/Small RangeScrollBar Large/Small Range