如何知道用户单击了“ X”或“关闭”按钮？

在MSDN中，我发现CloseReason.UserClosing知道用户已决定关闭表单，但是我想单击X按钮或单击关闭按钮都是一样的。那么如何在我的代码中区分这两者呢？

谢谢大家

假设您要使用WinForms，则可以使用FormClosing（）事件。每当关闭表单时都会触发FormClosing（）事件。

要检测用户是单击X还是单击CloseButton，可以通过sender对象获得它。尝试将发送方转换为Button控件，例如，验证其名称为“ CloseButton”。

private void Form1_FormClosing(object sender, FormClosingEventArgs e) {
    if (string.Equals((sender as Button).Name, @"CloseButton"))
        // Do something proper to CloseButton.
    else
        // Then assume that X has been clicked and act accordingly.
}

否则，我从来不需要区分是单击X还是单击CloseButton，因为我想对FormClosing事件执行特定的操作，例如在关闭MDIContainerForm之前关闭所有MdiChildren或对未保存的更改进行事件检查。在我看来，在这种情况下，我们不需要区别于两个按钮。

用ALT+ 关闭F4也会触发FormClosing（）事件，因为它将向窗体发送一条消息，要求关闭。您可以通过设置

FormClosingEventArgs.Cancel = true. 

在我们的示例中，这将转化为

e.Cancel = true.

注意FormClosing（）和FormClosed（）事件之间的区别。

当表单收到要关闭的消息，并在关闭消息之前验证它是否有事时，就会发生FormClosing。

FormClosed发生在窗体实际关闭时，因此在窗体关闭之后。

这有帮助吗？

CloseReason您在MSDN上找到的枚举仅用于检查用户是否关闭了该应用程序，或者是由于关闭而导致的，还是由任务管理器关闭了等等。

您可以根据原因执行不同的操作，例如：

void Form_FormClosing(object sender, FormClosingEventArgs e)
{
    if(e.CloseReason == CloseReason.UserClosing)
        // Prompt user to save his data

    if(e.CloseReason == CloseReason.WindowsShutDown)
        // Autosave and clear up ressources
}

但是，就像您猜到的那样，单击x按钮，或右键单击任务栏，然后单击“关闭”，或按Alt F4等等之间没有什么区别。所有这些都是有CloseReason.UserClosing原因的。

“ X”按钮注册为，DialogResult.Cancel因此另一个选择是评估DialogResult。

如果表单上有多个按钮，则可能已经将不同的DialogResults与每个按钮相关联，这将为您提供分辨每个按钮之间差异的方法。

（实施例：btnSubmit.DialogResult = DialogResult.OK，btnClose.DialogResult = Dialogresult.Abort）

    public Form1()
    {
        InitializeComponent();

        this.FormClosing += Form1_FormClosing;
    }

    /// <summary>
    /// Override the Close Form event
    /// Do something
    /// </summary>
    /// <param name="sender"></param>
    /// <param name="e"></param>
    private void Form1_FormClosing(Object sender, FormClosingEventArgs e)
    {
        //In case windows is trying to shut down, don't hold the process up
        if (e.CloseReason == CloseReason.WindowsShutDown) return;

        if (this.DialogResult == DialogResult.Cancel)
        {
            // Assume that X has been clicked and act accordingly.
            // Confirm user wants to close
            switch (MessageBox.Show(this, "Are you sure?", "Do you still want ... ?", MessageBoxButtons.YesNo, MessageBoxIcon.Question))
            {
                //Stay on this form
                case DialogResult.No:
                    e.Cancel = true;
                    break;
                default:
                    break;
            }
        }
    }

如何检测是否通过单击X按钮或通过调用Close()代码关闭了表单？

您不能依赖于表单关闭事件args的关闭原因，因为如果用户单击标题栏上的X按钮或使用Alt + F4关闭该表单或使用系统菜单关闭该表单或通过调用Close()方法关闭该表单，则全部在上述情况下，关闭原因将由用户关闭这是不希望的结果。

要区分是通过X按钮还是通过Close方法关闭表单，可以使用以下任一选项：

• 处理WM_SYSCOMMAND并检查SC_CLOSE并设置标志。
• 检查StackTrace以查看是否有任何框架包含Close方法调用。

示例1-句柄 WM_SYSCOMMAND

public bool ClosedByXButtonOrAltF4 {get; private set;}
private const int SC_CLOSE = 0xF060;
private const int WM_SYSCOMMAND = 0x0112;
protected override void WndProc(ref Message msg)
{
    if (msg.Msg == WM_SYSCOMMAND && msg.WParam.ToInt32() == SC_CLOSE)
        ClosedByXButtonOrAltF4 = true;
    base.WndProc(ref msg);
}
protected override void OnShown(EventArgs e)
{
    ClosedByXButtonOrAltF4 = false;
}   
protected override void OnFormClosing(FormClosingEventArgs e)
{
    if (ClosedByXButtonOrAltF4)
        MessageBox.Show("Closed by X or Alt+F4");
    else
        MessageBox.Show("Closed by calling Close()");
}

示例2-检查StackTrace

protected override void OnFormClosing(FormClosingEventArgs e)
{
    if (new StackTrace().GetFrames().Any(x => x.GetMethod().Name == "Close"))
        MessageBox.Show("Closed by calling Close()");
    else
        MessageBox.Show("Closed by X or Alt+F4");
}

它确定是否关闭了表单（如果您的应用程序未附加到特定表单）何时关闭应用程序。

    private void MyForm_FormClosed(object sender, FormClosedEventArgs e)
    {
        if (Application.OpenForms.Count == 0) Application.Exit();
    }

我总是在我的应用程序中使用Form Close方法，该方法从退出按钮，alt + f4或启动了另一个关闭表单事件中捕获alt + x 。mstrClsTitle = "grmRexcel"在这种情况下，我所有的类都具有定义为“私有”字符串的类名，一个调用“表单关闭方法”的Exit方法和一个“表单关闭方法”。我也有一个关于表单关闭方法的声明-this.FormClosing = My Form Closing Form Closing method name。

此代码：

namespace Rexcel_II
{
    public partial class frmRexcel : Form
    {
        private string mstrClsTitle = "frmRexcel";

        public frmRexcel()
        {
            InitializeComponent();

            this.FormClosing += frmRexcel_FormClosing;
        }

        /// <summary>
        /// Handles the Button Exit Event executed by the Exit Button Click
        /// or Alt + x
        /// 
        /// </summary>
        /// <param name="sender"></param>
        /// <param name="e"></param>
        private void btnExit_Click(object sender, EventArgs e)
        {            
            this.Close();        
        }


        /// <summary>
        /// Handles the Form Closing event
        /// 
        /// </summary>
        /// <param name="sender"></param>
        /// <param name="e"></param>
        private void frmRexcel_FormClosing(object sender, FormClosingEventArgs e)
        {

            // ---- If windows is shutting down, 
            // ---- I don't want to hold up the process
            if (e.CloseReason == CloseReason.WindowsShutDown) return;
            {

                // ---- Ok, Windows is not shutting down so
                // ---- either btnExit or Alt + x or Alt + f4 has been clicked or
                // ---- another form closing event was intiated
                //      *)  Confirm user wants to close the application
                switch (MessageBox.Show(this, 
                                    "Are you sure you want to close the Application?",
                                    mstrClsTitle + ".frmRexcel_FormClosing",
                                    MessageBoxButtons.YesNo, MessageBoxIcon.Question))
                {

                    // ---- *)  if No keep the application alive 
                    //----  *)  else close the application
                    case DialogResult.No:
                        e.Cancel = true;
                        break;
                    default:
                        break;
                }
            }
        }
    }
}

您可以尝试从设计中添加事件处理程序，如下所示：在设计视图中打开表单，打开属性窗口或按F4，单击事件工具栏按钮以查看Form对象上的事件，在“行为”组中找到FormClosing事件，然后双击它。参考：https : //social.msdn.microsoft.com/Forums/vstudio/en-US/9bdee708-db4b-4e46-a99c-99726fa25cfb/how-do-i-add-formclosing-event?forum=csharpgeneral

if (this.DialogResult == DialogResult.Cancel)
        {

        }
        else
        {
            switch (e.CloseReason)
            {
                case CloseReason.UserClosing:
                    e.Cancel = true;
                    break;
            }
        }

当用户单击表单上的“ X”或关闭按钮时是否执行条件。当用户单击Alt + f4出于任何其他目的时，可以使用else

namespace Test
{
    public partial class Member : Form
    {
        public Member()
        {
            InitializeComponent();
        }

        private bool xClicked = true;

        private void btnClose_Click(object sender, EventArgs e)
        {
            xClicked = false;
            Close();
        }

        private void Member_FormClosing(object sender, FormClosingEventArgs e)
        {
            if (xClicked)
            {
                // user click the X
            } 
            else 
            {
                // user click the close button
            }
        }
    }
}

我同意DialogResult-Solution作为更直接的解决方案。

但是，在VB.NET中，必须进行类型转换才能获得CloseReason-Property

    Private Sub MyForm_Closing(sender As Object, e As CancelEventArgs) Handles Me.Closing

        Dim eCast As System.Windows.Forms.FormClosingEventArgs
        eCast = TryCast(e, System.Windows.Forms.FormClosingEventArgs)
        If eCast.CloseReason = Windows.Forms.CloseReason.None Then
            MsgBox("Button Pressed")
        Else
            MsgBox("ALT+F4 or [x] or other reason")
        End If

    End Sub

我还必须在窗体的“ InitializeComponent（）”方法中注册关闭函数：

private void InitializeComponent() {
// ...
this.FormClosing += FrmMain_FormClosing;
// ...
}

我的“ FormClosing”函数看起来类似于给定的答案（https://stackoverflow.com/a/2683846/3323790）：

private void FrmMain_FormClosing(object sender, FormClosingEventArgs e) {
    if (e.CloseReason == CloseReason.UserClosing){
        MessageBox.Show("Closed by User", "UserClosing");
    }

    if (e.CloseReason == CloseReason.WindowsShutDown){
        MessageBox.Show("Closed by Windows shutdown", "WindowsShutDown");
    }
}

还有一件事要提到：还有一个“ FormClosed”函数，发生在“ FormClosing”之后。要使用此功能，请如下所示进行注册：

this.FormClosed += MainPage_FormClosed;

private void MainPage_FormClosing(object sender, FormClosingEventArgs e)
{
// your code after the form is closed
}

我已经做了这样的事情。

private void Form_FormClosing(object sender, FormClosingEventArgs e)
    {
        if ((sender as Form).ActiveControl is Button)
        {
            //CloseButton
        }
        else
        {
            //The X has been clicked
        }
    }