在 MouseDown 事件中区分单击和双击

区分鼠标单击和双击事件

处理 MouseDown 事件并确定单击位置和两次单击间的时间间隔，
方法是使用适当的 SystemInformation 属性和 Timer 组件。
根据发生的是单击还是双击，执行适当的操作。下面的代码示例阐释这是如何实现的。

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

namespace SingleVersusDoubleClick
{
class Form1 : Form
{
private Rectangle hitTestRectangle = new Rectangle();
private Rectangle doubleClickRectangle = new Rectangle();
private TextBox textBox1 = new TextBox();
private Timer doubleClickTimer = new Timer();
private ProgressBar doubleClickBar = new ProgressBar();
private Label label1 = new Label();
private Label label2 = new Label();
private bool isFirstClick = true ;
private bool isDoubleClick = false ;
private int milliseconds = 0 ;

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

public Form1()
{
label1.Location = new Point( 30 , 5 );
label1.Size = new Size( 100 , 15 );
label1.Text = " Hit test rectangle: " ;

label2.Location = new Point( 30 , 70 );
label2.Size = new Size( 100 , 15 );
label2.Text = " Double click timer: " ;

hitTestRectangle.Location = new Point( 30 , 20 );
hitTestRectangle.Size = new Size( 100 , 40 );

doubleClickTimer.Interval = 100 ;
doubleClickTimer.Tick +=
new EventHandler(doubleClickTimer_Tick);

doubleClickBar.Location = new Point( 30 , 85 );
doubleClickBar.Minimum = 0 ;
doubleClickBar.Maximum = SystemInformation.DoubleClickTime;

textBox1.Location = new Point( 30 , 120 );
textBox1.Size = new Size( 200 , 100 );
textBox1.AutoSize = false ;
textBox1.Multiline = true ;

this .Paint += new PaintEventHandler(Form1_Paint);
this .MouseDown += new MouseEventHandler(Form1_MouseDown);
this .Controls.AddRange( new Control[] { doubleClickBar, textBox1,
label1, label2 });
}

// Detect a valid single click or double click.
void Form1_MouseDown( object sender, MouseEventArgs e)
{
// Verify that the mouse click is in the main hit
// test rectangle.
if ( ! hitTestRectangle.Contains(e.Location))
{
return ;
}

// This is the first mouse click.
if (isFirstClick)
{
isFirstClick = false ;

// Determine the location and size of the double click
// rectangle area to draw around the cursor point.
doubleClickRectangle = new Rectangle(
e.X - (SystemInformation.DoubleClickSize.Width / 2 ),
e.Y - (SystemInformation.DoubleClickSize.Height / 2 ),
SystemInformation.DoubleClickSize.Width,
SystemInformation.DoubleClickSize.Height);
Invalidate();

// Start the double click timer.
doubleClickTimer.Start();
}

// This is the second mouse click.
else
{
// Verify that the mouse click is within the double click
// rectangle and is within the system-defined double
// click period.
if (doubleClickRectangle.Contains(e.Location) &&
milliseconds < SystemInformation.DoubleClickTime)
{
isDoubleClick = true ;
}
}
}

void doubleClickTimer_Tick( object sender, EventArgs e)
{
milliseconds += 100 ;
doubleClickBar.Increment( 100 );

// The timer has reached the double click time limit.
if (milliseconds >= SystemInformation.DoubleClickTime)
{
doubleClickTimer.Stop();

if (isDoubleClick)
{
textBox1.AppendText( " Perform double click action " );
textBox1.AppendText(Environment.NewLine);
}
else
{
textBox1.AppendText( " Perform single click action " );
textBox1.AppendText(Environment.NewLine);
}

// Allow the MouseDown event handler to process clicks again.
isFirstClick = true ;
isDoubleClick = false ;
milliseconds = 0 ;
doubleClickBar.Value = 0 ;
}
}

// Paint the hit test and double click rectangles.
void Form1_Paint( object sender, PaintEventArgs e)
{
// Draw the border of the main hit test rectangle.
e.Graphics.DrawRectangle(Pens.Black, hitTestRectangle);

// Fill in the double click rectangle.
e.Graphics.FillRectangle(Brushes.Blue, doubleClickRectangle);
}
}
}

 

代码源于MSDN