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TrackBar.ValueChanged Event

Occurs when the Value property of a track bar changes, either by movement of the scroll box or by manipulation in code.

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

public event EventHandler ValueChanged

You can use this event to update other controls when the value represented in the track bar changes.

For more information about handling events, see Consuming Events.

The following code example demonstrates how to use the TickStyle, Minimum, and Maximum members and how to handle the ValueChanged event. To run the example, paste the following code into a form that contains a TrackBar control name TrackBar1 and a TextBox control named TextBox1. Call the InitializeTrackBar method from the form's constructor or Load event-handling method.


	//Declare a new TrackBar object. 
	internal System.Windows.Forms.TrackBar TrackBar1;

	// Initalize the TrackBar and add it to the form. 
	private void InitializeTrackBar()
	{
		this.TrackBar1 = new System.Windows.Forms.TrackBar();
		TrackBar1.Location = new System.Drawing.Point(75, 30);

		// Set the TickStyle property so there are ticks on both sides 
		// of the TrackBar.
		TrackBar1.TickStyle = TickStyle.Both;

		// Set the minimum and maximum number of ticks.
		TrackBar1.Minimum = 10;
		TrackBar1.Maximum = 100;

		// Set the tick frequency to one tick every ten units.
		TrackBar1.TickFrequency = 10;

		// Associate the event-handling method with the  
		// ValueChanged event.
		TrackBar1.ValueChanged += 
			new System.EventHandler(TrackBar1_ValueChanged);
		this.Controls.Add(this.TrackBar1);
	}
	

	// Handle the TrackBar.ValueChanged event by calculating a value for 
	// TextBox1 based on the TrackBar value.   
	private void TrackBar1_ValueChanged(object sender, System.EventArgs e)
	{
		TextBox1.Text = (System.Math.Round(TrackBar1.Value/10.0)).ToString();
	}

.NET Framework

Supported in: 4.5.2, 4.5.1, 4.5, 4, 3.5, 3.0, 2.0, 1.1, 1.0

.NET Framework Client Profile

Supported in: 4, 3.5 SP1

Windows 8.1, Windows Server 2012 R2, Windows 8, Windows Server 2012, Windows 7, Windows Vista SP2, Windows Server 2008 (Server Core Role not supported), Windows Server 2008 R2 (Server Core Role supported with SP1 or later; Itanium not supported)

The .NET Framework does not support all versions of every platform. For a list of the supported versions, see .NET Framework System Requirements.

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