C# TrackBar.SmallChange属性代码示例

//引入命名空间
using System;
using System.Drawing;
using System.Windows.Forms;

public class Form1 : System.Windows.Forms.Form
{
    private System.Windows.Forms.TrackBar trackBar1;
    private System.Windows.Forms.TextBox textBox1;

    [STAThread]
    static void Main() 
    {
        Application.Run(new Form1());
    }

    public Form1()
    {
        this.textBox1 = new System.Windows.Forms.TextBox();
        this.trackBar1 = new System.Windows.Forms.TrackBar();

        // TextBox for TrackBar.Value update.
        this.textBox1.Location = new System.Drawing.Point(240, 16);
        this.textBox1.Size = new System.Drawing.Size(48, 20);

        // Set up how the form should be displayed and add the controls to the form.
        this.ClientSize = new System.Drawing.Size(296, 62);
        this.Controls.AddRange(new System.Windows.Forms.Control[] {this.textBox1,this.trackBar1});
        this.Text = "TrackBar Example";

        // Set up the TrackBar.
        this.trackBar1.Location = new System.Drawing.Point(8, 8);
        this.trackBar1.Size = new System.Drawing.Size(224, 45);
        this.trackBar1.Scroll += new System.EventHandler(this.trackBar1_Scroll);

        // The Maximum property sets the value of the track bar when
        // the slider is all the way to the right.
        trackBar1.Maximum = 30;
        
        // The TickFrequency property establishes how many positions
        // are between each tick-mark.
        trackBar1.TickFrequency = 5;

        // The LargeChange property sets how many positions to move
        // if the bar is clicked on either side of the slider.
        trackBar1.LargeChange = 3;

        // The SmallChange property sets how many positions to move
        // if the keyboard arrows are used to move the slider.
        trackBar1.SmallChange = 2;
    }

    private void trackBar1_Scroll(object sender, System.EventArgs e)
    {
        // Display the trackbar value in the text box.
        textBox1.Text = "" + trackBar1.Value;
    }
}

//引入命名空间
using System;
using System.Drawing;
using System.Windows.Forms;

public class TrackBars : Form
{
  Panel pnl;
  PictureBox pb;
  TrackBar htbar;
  TrackBar vtbar;

  public TrackBars()
  {
    Size = new Size(500,520);

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

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

    pb = new PictureBox();
    pb.Parent = pnl;
    pb.Size = new Size(200, 200);
    pb.Location = new Point((pnl.Size.Width / 2) - (pb.Size.Width / 2),
                (pnl.Size.Height / 2) - (pb.Size.Height /2));
    pb.BorderStyle = BorderStyle.FixedSingle;
    pb.SizeMode = PictureBoxSizeMode.StretchImage;
    pb.Image = img;

    htbar = new TrackBar();
    htbar.Parent = this;
    htbar.Orientation = Orientation.Horizontal;
    htbar.Size = new Size(pnl.Width, 10);
    htbar.Location = new Point(pnl.Left, pnl.Bottom + 25);
    htbar.TickStyle = TickStyle.BottomRight;
    htbar.TickFrequency = 25;
    htbar.Minimum = 25;
    htbar.Maximum = 400;
    htbar.SmallChange = 10;
    htbar.LargeChange = 25;
    htbar.BackColor = Color.Yellow;
    htbar.Value = pb.Width;
    htbar.ValueChanged += new EventHandler(htbar_OnValueChanged);

    vtbar = new TrackBar();
    vtbar.Parent = this;
    vtbar.Orientation = Orientation.Vertical;
    vtbar.Size = new Size(25, pnl.Height);  
    vtbar.Location = new Point(pnl.Right + 25, pnl.Top);
    vtbar.TickStyle = TickStyle.Both;
    vtbar.SetRange(25,400);
    vtbar.SmallChange = 10;
    vtbar.LargeChange = 50;
    vtbar.TickFrequency = vtbar.Maximum / 20;
    vtbar.BackColor = Color.Pink;
    vtbar.Value = pb.Height;
    vtbar.ValueChanged += new EventHandler(vtbar_OnValueChanged);

  }

  private void htbar_OnValueChanged(object sender, EventArgs e)
  {
    pb.Size = new Size(htbar.Value, pb.Height);
  }

  private void vtbar_OnValueChanged(object sender, EventArgs e)
  {
    pb.Size = new Size(pb.Width, vtbar.Value);
  }

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