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TrackBar Class

Represents a standard Windows track bar.

For a list of all members of this type, see TrackBar Members.

System.Object
   System.MarshalByRefObject
      System.ComponentModel.Component
         System.Windows.Forms.Control
            System.Windows.Forms.TrackBar

[Visual Basic]
Public Class TrackBar
   Inherits Control
   Implements ISupportInitialize
[C#]
public class TrackBar : Control, ISupportInitialize
[C++]
public __gc class TrackBar : public Control, ISupportInitialize
[JScript]
public class TrackBar extends Control implements ISupportInitialize

Thread Safety

Any public static (Shared in Visual Basic) members of this type are thread safe. Any instance members are not guaranteed to be thread safe.

Remarks

The TrackBar is a scrollable control similar to the ScrollBar control. You can configure ranges through which the value of the Value property of a track bar scrolls by setting the Minimum property to specify the lower end of the range and the Maximum property to specify the upper end of the range.

The LargeChange property defines the increment to add or subtract from the Value property when clicks occur on either side of the slider. The track bar can be displayed horizontally or vertically.

You can use this control to input numeric data obtained through the Value property. You can display this numeric data in a control or use it in code.

Example

[Visual Basic, C#, C++] The following example displays a form containing a TrackBar control and a TextBox control. The example demonstrates setting the Maximum, TickFrequency, LargeChange, and SmallChange properties and handling the Scroll event. The TextBox contents are updated to the Value property value when the Scroll event occurs.

[Visual Basic] 
Imports System
Imports System.Drawing
Imports System.Windows.Forms

Public Class Form1
    Inherits System.Windows.Forms.Form

    Private WithEvents trackBar1 As System.Windows.Forms.TrackBar
    Private textBox1 As System.Windows.Forms.TextBox

    <System.STAThread()> _
    Public Shared Sub Main()
        System.Windows.Forms.Application.Run(New Form1)
    End Sub 'Main

    Public Sub New()
        Me.textBox1 = New System.Windows.Forms.TextBox
        Me.trackBar1 = New System.Windows.Forms.TrackBar

        ' TextBox for TrackBar.Value update.
        Me.textBox1.Location = New System.Drawing.Point(240, 16)
        Me.textBox1.Size = New System.Drawing.Size(48, 20)

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

        ' Set up the TrackBar.
        Me.trackBar1.Location = New System.Drawing.Point(8, 8)
        Me.trackBar1.Size = New System.Drawing.Size(224, 45)

        ' 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
    End Sub 'New

    Private Sub trackBar1_Scroll(ByVal sender As Object, _
                    ByVal e As System.EventArgs) Handles trackBar1.Scroll

        ' Display the trackbar value in the text box.
        textBox1.Text = trackBar1.Value
    End Sub 

End Class 'Form1

[C#] 
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;
    }
}

[C++] 

using namespace System;
using namespace System::Drawing;
using namespace System::Windows::Forms;

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

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

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

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

        // Set up the TrackBar.
        this->trackBar1->Location = System::Drawing::Point(8, 8);
        this->trackBar1->Size = System::Drawing::Size(224, 45);
        this->trackBar1->Scroll += new 
            System::EventHandler(this, &Form1::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 = String::Concat(S"", __box(trackBar1->Value));
    }
};

[STAThread]
int main() {
    Application::Run(new Form1());
}

[JScript] No example is available for JScript. To view a Visual Basic, C#, or C++ example, click the Language Filter button Language Filter in the upper-left corner of the page.

Requirements

Namespace: System.Windows.Forms

Platforms: Windows 98, Windows NT 4.0, Windows Millennium Edition, Windows 2000, Windows XP Home Edition, Windows XP Professional, Windows Server 2003 family, .NET Compact Framework

Assembly: System.Windows.Forms (in System.Windows.Forms.dll)

See Also

TrackBar Members | System.Windows.Forms Namespace

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