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Control.MouseDown Event

Occurs when the mouse pointer is over the control and a mouse button is pressed.

Namespace:  System.Windows.Forms
Assembly:  System.Windows.Forms (in System.Windows.Forms.dll)
public event MouseEventHandler MouseDown

Mouse events occur in the following order:

  1. MouseEnter

  2. MouseMove

  3. MouseHover / MouseDown / MouseWheel

  4. MouseUp

  5. MouseLeave

NoteNote

The following events are not raised for the TabControl class unless there is at least one TabPage in the TabControl.TabPages collection: Click, DoubleClick, MouseDown, MouseUp, MouseHover, MouseEnter, MouseLeave and MouseMove. If there is at least one TabPage in the collection, and the user interacts with the tab control's header (where the TabPage names appear), the TabControl raises the appropriate event. However, if the user interaction is within the client area of the tab page, the TabPage raises the appropriate event.

For more information about handling events, see Consuming Events.

The following code example demonstrates using different mouse events to draw the path of the mouse on a Panel. A line segment is added to the GraphicsPath for each MouseMove and MouseDown events that occur. To update the graphics, the Invalidate method is called for the Panel on each MouseDown and MouseUp event. In addition, the graphic path is scrolled up or down when the MouseWheel event occurs. Additional mouse events, like MouseHover, are identified on screen as well. Also displayed on the screen is additional information about the mouse from the SystemInformation class.

using System;
using System.Drawing;
using System.Windows.Forms;

namespace MouseEvent
{
    public class Form1 : System.Windows.Forms.Form
    {
        private System.Windows.Forms.Panel panel1;
        private System.Windows.Forms.Label label1;
        private System.Windows.Forms.Label label2;
        private System.Windows.Forms.Label label3;
        private System.Windows.Forms.Label label4;
        private System.Windows.Forms.Label label5;
        private System.Windows.Forms.Label label6;
        private System.Windows.Forms.Label label7;
        private System.Windows.Forms.Label label8;
        private System.Windows.Forms.Label label9;
        private System.Windows.Forms.Button clearButton;
        private System.Drawing.Drawing2D.GraphicsPath mousePath;
        private System.Windows.Forms.GroupBox groupBox1;

        private int fontSize = 20;        

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

        public Form1()
        {            
            mousePath = new System.Drawing.Drawing2D.GraphicsPath();

            this.panel1 = new System.Windows.Forms.Panel();
            this.label1 = new System.Windows.Forms.Label();
            this.clearButton = new System.Windows.Forms.Button();
            this.label2 = new System.Windows.Forms.Label();
            this.label3 = new System.Windows.Forms.Label();
            this.label4 = new System.Windows.Forms.Label();
            this.label5 = new System.Windows.Forms.Label();
            this.label6 = new System.Windows.Forms.Label();
            this.label7 = new System.Windows.Forms.Label();
            this.label8 = new System.Windows.Forms.Label();
            this.label9 = new System.Windows.Forms.Label();
            this.groupBox1 = new System.Windows.Forms.GroupBox();

            // Mouse Events Label 
            this.label1.Location = new System.Drawing.Point(24, 504);
            this.label1.Size = new System.Drawing.Size(392, 23);
            // DoubleClickSize Label 
            this.label2.AutoSize = true;
            this.label2.Location = new System.Drawing.Point(24, 48);
            this.label2.Size = new System.Drawing.Size(35, 13);
            // DoubleClickTime Label 
            this.label3.AutoSize = true;
            this.label3.Location = new System.Drawing.Point(24, 72);
            this.label3.Size = new System.Drawing.Size(35, 13);
            // MousePresent Label 
            this.label4.AutoSize = true;
            this.label4.Location = new System.Drawing.Point(24, 96);
            this.label4.Size = new System.Drawing.Size(35, 13);
            // MouseButtons Label 
            this.label5.AutoSize = true;
            this.label5.Location = new System.Drawing.Point(24, 120);
            this.label5.Size = new System.Drawing.Size(35, 13);
            // MouseButtonsSwapped Label 
            this.label6.AutoSize = true;
            this.label6.Location = new System.Drawing.Point(320, 48);
            this.label6.Size = new System.Drawing.Size(35, 13);
            // MouseWheelPresent Label 
            this.label7.AutoSize = true;
            this.label7.Location = new System.Drawing.Point(320, 72);
            this.label7.Size = new System.Drawing.Size(35, 13);
            // MouseWheelScrollLines Label 
            this.label8.AutoSize = true;
            this.label8.Location = new System.Drawing.Point(320, 96);
            this.label8.Size = new System.Drawing.Size(35, 13);
            // NativeMouseWheelSupport Label 
            this.label9.AutoSize = true;
            this.label9.Location = new System.Drawing.Point(320, 120);
            this.label9.Size = new System.Drawing.Size(35, 13);

            // Mouse Panel 
            this.panel1.Anchor = ((System.Windows.Forms.AnchorStyles.Top | System.Windows.Forms.AnchorStyles.Left) 
                | System.Windows.Forms.AnchorStyles.Right);
            this.panel1.BackColor = System.Drawing.SystemColors.ControlDark;
            this.panel1.Location = new System.Drawing.Point(16, 160);
            this.panel1.Size = new System.Drawing.Size(664, 320);
            this.panel1.MouseUp += new System.Windows.Forms.MouseEventHandler(this.panel1_MouseUp);
            this.panel1.Paint += new System.Windows.Forms.PaintEventHandler(this.panel1_Paint);
            this.panel1.MouseEnter += new System.EventHandler(this.panel1_MouseEnter);
            this.panel1.MouseHover += new System.EventHandler(this.panel1_MouseHover);
            this.panel1.MouseMove += new System.Windows.Forms.MouseEventHandler(this.panel1_MouseMove);
            this.panel1.MouseLeave += new System.EventHandler(this.panel1_MouseLeave);
            this.panel1.MouseDown += new System.Windows.Forms.MouseEventHandler(this.panel1_MouseDown);
            this.panel1.MouseWheel += new System.Windows.Forms.MouseEventHandler(this.panel1_MouseWheel);

            // Clear Button 
            this.clearButton.Anchor = (System.Windows.Forms.AnchorStyles.Top | System.Windows.Forms.AnchorStyles.Right);
            this.clearButton.Location = new System.Drawing.Point(592, 504);
            this.clearButton.TabIndex = 1;
            this.clearButton.Text = "Clear";
            this.clearButton.Click += new System.EventHandler(this.clearButton_Click);

            // GroupBox 
            this.groupBox1.Anchor = ((System.Windows.Forms.AnchorStyles.Top | System.Windows.Forms.AnchorStyles.Left) 
                | System.Windows.Forms.AnchorStyles.Right);
            this.groupBox1.Location = new System.Drawing.Point(16, 24);
            this.groupBox1.Size = new System.Drawing.Size(664, 128);
            this.groupBox1.Text = "System.Windows.Forms.SystemInformation";

            // Set up how the form should be displayed and add the controls to the form. 
            this.ClientSize = new System.Drawing.Size(696, 534);
            this.Controls.AddRange(new System.Windows.Forms.Control[] {
                                        this.label9,this.label8,this.label7,this.label6,
                                        this.label5,this.label4,this.label3,this.label2,
                                        this.clearButton,this.panel1,this.label1,this.groupBox1});
            this.Text = "Mouse Event Example";

            // Displays information about the system mouse.
            label2.Text = "SystemInformation.DoubleClickSize: " + SystemInformation.DoubleClickSize.ToString();
            label3.Text = "SystemInformation.DoubleClickTime: " + SystemInformation.DoubleClickTime.ToString();
            label4.Text = "SystemInformation.MousePresent: " + SystemInformation.MousePresent.ToString();
            label5.Text = "SystemInformation.MouseButtons: " + SystemInformation.MouseButtons.ToString();
            label6.Text = "SystemInformation.MouseButtonsSwapped: " + SystemInformation.MouseButtonsSwapped.ToString();
            label7.Text = "SystemInformation.MouseWheelPresent: " + SystemInformation.MouseWheelPresent.ToString();
            label8.Text = "SystemInformation.MouseWheelScrollLines: " + SystemInformation.MouseWheelScrollLines.ToString();
            label9.Text = "SystemInformation.NativeMouseWheelSupport: " + SystemInformation.NativeMouseWheelSupport.ToString();

        }

        private void panel1_MouseDown(object sender, System.Windows.Forms.MouseEventArgs e) 
        {
            // Update the mouse path with the mouse information
            Point mouseDownLocation = new Point(e.X, e.Y);

            string eventString = null;
            switch (e.Button) {
                case MouseButtons.Left:
                    eventString = "L";
                    break;
                case MouseButtons.Right:
                    eventString = "R";
                    break;
                case MouseButtons.Middle:
                    eventString = "M";
                    break;
                case MouseButtons.XButton1:
                    eventString = "X1";
                    break;
                case MouseButtons.XButton2:
                    eventString = "X2";
                    break;
                case MouseButtons.None:
                default:
                    break;
            }

            if (eventString != null) 
            {
                mousePath.AddString(eventString, FontFamily.GenericSerif, (int)FontStyle.Bold, fontSize, mouseDownLocation, StringFormat.GenericDefault);
            }
            else 
            {
                mousePath.AddLine(mouseDownLocation,mouseDownLocation);
            }
            panel1.Focus();
            panel1.Invalidate();
        }

        private void panel1_MouseEnter(object sender, System.EventArgs e) 
        {
            // Update the mouse event label to indicate the MouseEnter event occurred.
            label1.Text = sender.GetType().ToString() + ": MouseEnter";
        }

        private void panel1_MouseHover(object sender, System.EventArgs e) 
        {
            // Update the mouse event label to indicate the MouseHover event occurred.
            label1.Text = sender.GetType().ToString() + ": MouseHover";
        }

        private void panel1_MouseLeave(object sender, System.EventArgs e) 
        {
            // Update the mouse event label to indicate the MouseLeave event occurred.
            label1.Text = sender.GetType().ToString() + ": MouseLeave";
        }

        private void panel1_MouseMove(object sender, System.Windows.Forms.MouseEventArgs e)
        {
            // Update the mouse path that is drawn onto the Panel. 
            int mouseX = e.X;
            int mouseY = e.Y;

            mousePath.AddLine(mouseX,mouseY,mouseX,mouseY);
        }

        private void panel1_MouseWheel(object sender, System.Windows.Forms.MouseEventArgs e)
        {
            // Update the drawing based upon the mouse wheel scrolling. 

            int numberOfTextLinesToMove = e.Delta * SystemInformation.MouseWheelScrollLines / 120;
            int numberOfPixelsToMove = numberOfTextLinesToMove * fontSize;

            if (numberOfPixelsToMove != 0) {
                System.Drawing.Drawing2D.Matrix translateMatrix = new  System.Drawing.Drawing2D.Matrix();
                translateMatrix.Translate(0, numberOfPixelsToMove);
                mousePath.Transform(translateMatrix);
            }
            panel1.Invalidate();
        }
        private void panel1_MouseUp(object sender, System.Windows.Forms.MouseEventArgs e) 
        {
            Point mouseUpLocation = new System.Drawing.Point(e.X, e.Y);

            // Show the number of clicks in the path graphic. 
            int numberOfClicks = e.Clicks;
            mousePath.AddString("    " + numberOfClicks.ToString(), 
                        FontFamily.GenericSerif, (int)FontStyle.Bold, 
                        fontSize, mouseUpLocation, StringFormat.GenericDefault);

            panel1.Invalidate();
        }

        private void panel1_Paint(object sender, System.Windows.Forms.PaintEventArgs e) 
        {    
            // Perform the painting of the Panel.
            e.Graphics.DrawPath(System.Drawing.Pens.DarkRed, mousePath);
        }

        private void clearButton_Click(object sender, System.EventArgs e)
        {
            // Clear the Panel display.
            mousePath.Dispose();
            mousePath = new System.Drawing.Drawing2D.GraphicsPath();
            panel1.Invalidate();
        }
    }
}

.NET Framework

Supported in: 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 Phone 8.1, Windows Phone 8, 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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