检查在 Powershell 中关闭 Windows 窗体的原因

Question

想知道是否有办法检查关闭窗口的事件，几乎是点击右上角的红色 x 或者是否调用了 $form.Close()？

如果我的脚本中有$form.Add_Closing({})，每个人都会自动启动它，但我想知道关闭窗口的方式是什么。

Answer 1

FormClosing event 参数对象的 .CloseReason 属性不允许您区分已在表单上调用的 .Close() 方法和用户通过标题栏/窗口系统菜单/按 Alt+F4 - 所有这些情况同样导致.CloseReason property反映枚举值UserClosing。

但是，您可以通过检查调用堆栈以查找对 .Close() 方法的调用，从而在主题上调整 Reza Aghaei's helpful C# answer 中的技术：

using assembly System.Windows.Forms
using namespace System.Windows.Forms
using namespace System.Drawing

# Create a sample form.
$form = [Form] @{
    ClientSize      = [Point]::new(400,100)
    Text            = 'Closing Demo'
}    

# Create a button and add it to the form.
$form.Controls.AddRange(@(
    ($btnClose = [Button] @{
        Text              = 'Close'
        Location          = [Point]::new(160, 60)
    })
))

# Make the button call $form.Close() when clicked.
$btnClose.add_Click({
  $form.Close()
})

# The event handler called when the form is closing.
$form.add_Closing({
  # Look for a call to a `.Close()` method on the call stack.
  if ([System.Diagnostics.StackTrace]::new().GetFrames().GetMethod().Name -ccontains 'Close') {
    Write-Host 'Closed with .Close() method.'
  } else {
    Write-Host 'Closed via title bar / Alt+F4.'
  }
})

$null = $form.ShowDialog() # Show the form modally.
$form.Dispose()            # Dispose of the form.

如果您运行此代码并尝试各种关闭表单的方法，则会显示一条指示所使用方法的消息（.Close() 调用与标题栏/Alt+F4）。

注意：

• 通过分配给表单的.CancelButton 和.SubmitButton 属性但没有明确的$form.Close() 调用的按钮关闭表单仍会导致.Close() 在后台被调用。

• 代码需要 PowerShell v5+，但它可以适应早期版本。

Answer 2

检查调用堆栈工作正常，您可以依赖它。

为了完整起见，特别是对于您找到 C# 示例并希望在 PowerShell 中以简单的方式使用它的情况，我将分享一个示例，展示如何处理 WM_SYSCOMMAND，如我的linked post，在 PowerShell 中。

using assembly System.Windows.Forms
using namespace System.Windows.Forms
using namespace System.Drawing

# Create the C# derived Form
$assemblies = "System.Windows.Forms", "System.Drawing"
$code = @'
using System;
using System.Windows.Forms;
public class MyForm:Form
{
    public bool ClosedByXButtonOrAltF4 { get; private set;}
    public const int SC_CLOSE = 0xF060;
    public 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;
    }    
}
'@
Add-Type -ReferencedAssemblies $assemblies -TypeDefinition $code -Language CSharp   

# Create an instance of MyForm.
$form = [MyForm] @{
    ClientSize      = [Point]::new(400,100)
    Text            = "Closing Demo"
}    

# Create a button and add it to the form.
$form.Controls.AddRange(@(
    ($btnClose = [Button] @{
        Text              = "Close"
        Location          = New-Object System.Drawing.Point 160, 60
    })
))

# Make the button call $form.Close() when clicked.
$btnClose.add_Click({
  $form.Close()
})

# The event handler called when the form is closing.
$form.add_Closing({
  if ($form.ClosedByXButtonOrAltF4) {
    Write-Host 'Closed via title bar / Alt+F4.'
  } else {
    Write-Host 'Closed with .Close() method.'
  }
})

$null = $form.ShowDialog()
$form.Dispose()