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MouseEventArgs Class

Provides data for the MouseUp, MouseDown, and MouseMove events.

Namespace:  System.Windows.Forms
Assembly:  System.Windows.Forms (in System.Windows.Forms.dll)
[ComVisibleAttribute(true)]
public class MouseEventArgs : EventArgs

The MouseDown event occurs when the user presses the mouse button while the pointer is over a control. The MouseUp event occurs when the user releases the mouse button while the pointer remains over the control. The MouseMove event occurs when the user moves the mouse pointer over a control. A MouseEventArgs specifies which mouse button is pressed, how many times the mouse button was pressed and released, the coordinates of the mouse, and the amount the mouse wheel moved.

It is possible to receive a MouseDown event without a corresponding MouseUp, if the user switches focus to another application before releasing the mouse button.

These three events exist for the Control, AxHost, and NotifyIcon classes.

For information about the event model, see Events and Delegates.

The following code examples handles the MouseDown event on a TextBox control so that clicking the right mouse button selects all of the text in the control. This example requires that you have a form with a TextBox control named textBox1.

private void Form1_Load(object sender, EventArgs e)
{
    // This line suppresses the default context menu for the TextBox control. 
    textBox1.ContextMenu = new ContextMenu();
    textBox1.MouseDown += new MouseEventHandler(textBox1_MouseDown);
}

void textBox1_MouseDown(object sender, System.Windows.Forms.MouseEventArgs e)
{
    if (e.Button == MouseButtons.Right)
    {
        textBox1.Select(0, textBox1.Text.Length);
    }
}

The following code example uses the Location property to track left mouse clicks and draw a series of straight line segments in response to user input. The example does not redraw the lines if you hide the form and then redisplay it; this code has been omitted for simplicity.

Point firstPoint;
Boolean haveFirstPoint;

public void EnableDrawing()
{
    this.MouseDown += new MouseEventHandler(Form1_MouseDownDrawing);
}

void Form1_MouseDownDrawing(object sender, System.Windows.Forms.MouseEventArgs e)
{
    if (haveFirstPoint)
    {
        Graphics g = this.CreateGraphics();
        g.DrawLine(Pens.Black, firstPoint, e.Location);
        haveFirstPoint = false;
    }
    else
    {
        firstPoint = e.Location;
        haveFirstPoint = true;
    }
}

The following code example uses the X and Y properties to display the current position of the mouse pointer in a ToolTip window.

ToolTip trackTip;

private void TrackCoordinates()
{
    trackTip = new ToolTip();
    this.MouseMove += new MouseEventHandler(Form1_MouseMove);
}

void Form1_MouseMove(object sender, System.Windows.Forms.MouseEventArgs e)
{
    String tipText = String.Format("({0}, {1})", e.X, e.Y);
    trackTip.Show(tipText, this, e.Location);
}
Any public static (Shared in Visual Basic) members of this type are thread safe. Any instance members are not guaranteed to be thread safe.

Windows 7, Windows Vista, Windows XP SP2, Windows XP Media Center Edition, Windows XP Professional x64 Edition, Windows XP Starter Edition, Windows Server 2008 R2, Windows Server 2008, Windows Server 2003, Windows Server 2000 SP4, Windows Millennium Edition, Windows 98, Windows CE, Windows Mobile for Pocket PC

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

.NET Framework

Supported in: 3.5, 3.0, 2.0, 1.1, 1.0

.NET Compact Framework

Supported in: 3.5, 2.0, 1.0
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