如何区分单击和双击（Windows 窗体 .NET）

项目
10/13/2023

通常情况下，一次单击会启动一个用户界面操作，而一次双击则会扩展该操作。例如，一次单击通常可选择一个项，而双击则可编辑所选的项。但是，Windows 窗体 Click 事件无法轻松应用于单击和双击执行多个不兼容操作的方案，因为绑定到 Click 或 MouseClick 事件的操作会在操作绑定到 DoubleClick 或 MouseDoubleClick 事件之前执行。本主题演示此问题的两种解决方案。

重要

面向 .NET 7 和 .NET 6 的桌面指南文档正在撰写中。

一种解决方案是处理双击事件，并回滚单击事件处理过程中的操作。在极少数情况下，可能需要通过处理 MouseDown 事件并使用 SystemInformation 类的 DoubleClickTime 和 DoubleClickSize 属性来模拟单击和双击行为。度量点击之间的时间，如果在达到 DoubleClickTime 值之前发生第二次单击，并且单击发生在由 DoubleClickSize 定义的矩形范围内，请执行双击操作；否则，请执行单击操作。

回滚单击操作

请确保你正在使用的控件具有标准双击行为。如果不具有标准双击行为，请启用具有 SetStyle 方法的控件。处理双击事件，并回滚单击操作以及双击操作。下面的代码示例演示了如何在启用了双击的情况下创建自定义按钮，以及如何回滚双击事件处理代码中的单击操作。

此代码示例使用可启用双击的新按钮控件：

public partial class DoubleClickButton : Button
{
    public DoubleClickButton()
    {
        // Set the style so a double click event occurs.
        SetStyle(ControlStyles.StandardClick | ControlStyles.StandardDoubleClick, true);
    }
}

Public Class DoubleClickButton : Inherits Button

    Public Sub New()
        SetStyle(ControlStyles.StandardClick Or ControlStyles.StandardDoubleClick, True)
    End Sub

End Class

下面的代码演示了窗体如何通过单击或双击新按钮控件来更改边框样式：

public partial class Form1 : Form
{
    private FormBorderStyle _initialStyle;
    private bool _isDoubleClicking;

    public Form1()
    {
        InitializeComponent();
    }

    private void Form1_Load(object sender, EventArgs e)
    {
        _initialStyle = this.FormBorderStyle;

        var button1 = new DoubleClickButton();
        button1.Location = new Point(50, 50);
        button1.Size = new Size(200, 23);
        button1.Text = "Click or Double Click";
        button1.Click += Button1_Click;
        button1.DoubleClick += Button1_DoubleClick;

        Controls.Add(button1);
    }

    private void Button1_DoubleClick(object sender, EventArgs e)
    {
        // This flag prevents the click handler logic from running
        // A double click raises the click event twice.
        _isDoubleClicking = true;
        FormBorderStyle = _initialStyle;
    }

    private void Button1_Click(object sender, EventArgs e)
    {
        if (_isDoubleClicking)
            _isDoubleClicking = false;
        else
            FormBorderStyle = FormBorderStyle.FixedToolWindow;
    }
}

Partial Public Class Form1

    Private _initialStyle As FormBorderStyle
    Private _isDoubleClicking As Boolean

    Public Sub New()
        InitializeComponent()
    End Sub

    Private Sub Form1_Load(sender As Object, e As EventArgs) Handles MyBase.Load
        Dim button1 As New DoubleClickButton

        _initialStyle = FormBorderStyle

        button1.Location = New Point(50, 50)
        button1.Size = New Size(200, 23)
        button1.Text = "Click or Double Click"

        AddHandler button1.Click, AddressOf Button1_Click
        AddHandler button1.DoubleClick, AddressOf Button1_DoubleClick

        Controls.Add(button1)

    End Sub

    Private Sub Button1_DoubleClick(sender As Object, e As EventArgs)
        ' This flag prevents the click handler logic from running
        ' A double click raises the click event twice.
        _isDoubleClicking = True
        FormBorderStyle = _initialStyle
    End Sub

    Private Sub Button1_Click(sender As Object, e As EventArgs)
        If _isDoubleClicking Then
            _isDoubleClicking = False
        Else
            FormBorderStyle = FormBorderStyle.FixedToolWindow
        End If
    End Sub
End Class

区分点击

请使用 SystemInformation 属性和 Timer 组件来处理 MouseDown 事件和确定点击之间的位置和时间跨度。根据是否发生单击或双击执行相应的操作。下面的代码示例演示如何实现这一点。

using System;
using System.Collections.Generic;
using System.ComponentModel;
using System.Drawing;
using System.Windows.Forms;

namespace project
{
    public partial class Form2 : Form
    {
        private DateTime _lastClick;
        private bool _inDoubleClick;
        private Rectangle _doubleClickArea;
        private TimeSpan _doubleClickMaxTime;
        private Action _doubleClickAction;
        private Action _singleClickAction;
        private Timer _clickTimer;

        public Form2()
        {
            InitializeComponent();
            _doubleClickMaxTime = TimeSpan.FromMilliseconds(SystemInformation.DoubleClickTime);

            _clickTimer = new Timer();
            _clickTimer.Interval = SystemInformation.DoubleClickTime;
            _clickTimer.Tick += ClickTimer_Tick;

            _singleClickAction = () => MessageBox.Show("Single clicked");
            _doubleClickAction = () => MessageBox.Show("Double clicked");
        }

        private void Form2_MouseDown(object sender, MouseEventArgs e)
        {
            if (_inDoubleClick)
            {
                _inDoubleClick = false;

                TimeSpan length = DateTime.Now - _lastClick;

                // If double click is valid, respond
                if (_doubleClickArea.Contains(e.Location) && length < _doubleClickMaxTime)
                {
                    _clickTimer.Stop();
                    _doubleClickAction();
                }

                return;
            }

            // Double click was invalid, restart 
            _clickTimer.Stop();
            _clickTimer.Start();
            _lastClick = DateTime.Now;
            _inDoubleClick = true;
            _doubleClickArea = new Rectangle(e.Location - (SystemInformation.DoubleClickSize / 2), 
                                             SystemInformation.DoubleClickSize);
        }

        private void ClickTimer_Tick(object sender, EventArgs e)
        {
            // Clear double click watcher and timer
            _inDoubleClick = false;
            _clickTimer.Stop();

            _singleClickAction();
        }
    }
}

Imports System.Drawing
Imports System.Windows.Forms

Public Class Form2
    Private _lastClick As Date
    Private _inDoubleClick As Boolean
    Private _doubleClickArea As Rectangle
    Private _doubleClickMaxTime As TimeSpan
    Private _singleClickAction As Action
    Private _doubleClickAction As Action
    Private WithEvents _clickTimer As Timer

    Private Sub Form2_Load(sender As Object, e As EventArgs) Handles MyBase.Load
        _doubleClickMaxTime = TimeSpan.FromMilliseconds(SystemInformation.DoubleClickTime)

        _clickTimer = New Timer()
        _clickTimer.Interval = SystemInformation.DoubleClickTime

        _singleClickAction = Sub()
                                 MessageBox.Show("Single click")
                             End Sub

        _doubleClickAction = Sub()
                                 MessageBox.Show("Double click")
                             End Sub
    End Sub

    Private Sub Form2_MouseDown(sender As Object, e As MouseEventArgs) Handles MyBase.MouseDown
        If _inDoubleClick Then

            _inDoubleClick = False

            Dim length As TimeSpan = Date.Now - _lastClick

            ' If double click is valid, respond
            If _doubleClickArea.Contains(e.Location) And length < _doubleClickMaxTime Then
                _clickTimer.Stop()
                Call _doubleClickAction()
            End If

            Return
        End If

        ' Double click was invalid, restart 
        _clickTimer.Stop()
        _clickTimer.Start()
        _lastClick = Date.Now
        _inDoubleClick = True
        _doubleClickArea = New Rectangle(e.Location - (SystemInformation.DoubleClickSize / 2),
                                         SystemInformation.DoubleClickSize)
    End Sub

    Private Sub SingleClickTimer_Tick(sender As Object, e As EventArgs) Handles _clickTimer.Tick
        ' Clear double click watcher and timer
        _inDoubleClick = False
        _clickTimer.Stop()

        Call _singleClickAction()
    End Sub

End Class

如何区分单击和双击（Windows 窗体 .NET）

回滚单击操作

区分点击

另请参阅

反馈

其他资源