Forms 对动态生成的控件上的事件使用变量

我有一个函数

addtextbox

，它创建一个

TextBox

控件，并为它的事件处理程序分配一个块

我面临的问题是，该块可能是用全局名称空间调用的，而

Add TextBox

函数中声明的变量对其不可访问。我如何使它们易于访问

编辑：添加完整代码

Add-Type -AssemblyName System.Windows.Forms

Function Add-Control() {
    Param (
        [System.Windows.Forms.Form]$Form,
        [string]$ControlType,
        [System.Windows.Forms.Control]$AfterControl = $null,
        [int]$Padding = 0
    )

    $control = New-Object System.Windows.Forms.$ControlType

    $control.AutoSize = $true

    $x = 5
    $y = 5

    if ($AfterControl) {
        $y = $AfterControl.Location.Y + $AfterControl.Size.Height + $Padding
    }

    $control.Location = "5,$y"

    $form.Controls.Add($control)

    return $control
}

Function Add-TextBox() {
    Param (
        [System.Windows.Forms.Form]$Form,
        [string]$Placeholder = "",
        [System.Windows.Forms.Control]$AfterControl = $null,
        [int]$Padding = 0
    )

    $control = Add-Control -Form $Form -ControlType "TextBox" -AfterControl $AfterControl -Padding $Padding

    $control.Add_GotFocus({
        Write-Host "Placeholder is null: $($Placeholder -eq $null)"
        if ($this.Text -eq $Placeholder) {
            $this.ForeColor = "Black"
            $this.Text = ""
        }
    })

    $control.Add_LostFocus({
        if ($this.Text -eq "") {
            $this.ForeColor = "Darkgray"
            $this.Text = $Placeholder
        }
    })

    return $control
}

$form = New-Object system.Windows.Forms.Form

$textbox = Add-TextBox -Form $form -Placeholder "(XXXXXX, npr. 012345)"

$form.ShowDialog()

---

似乎我可以在脚本块上使用

.GetNewClosure（）

来捕获局部变量并保留它们

Add-Type -AssemblyName System.Windows.Forms

Function Add-Control() {
    Param (
        [System.Windows.Forms.Form]$Form,
        [string]$ControlType,
        [System.Windows.Forms.Control]$AfterControl = $null,
        [int]$Padding = 0
    )

    $control = New-Object System.Windows.Forms.$ControlType

    $control.AutoSize = $true

    $x = 5
    $y = 5

    if ($AfterControl) {
        $y = $AfterControl.Location.Y + $AfterControl.Size.Height + $Padding
    }

    $control.Location = "5,$y"

    $form.Controls.Add($control)

    return $control
}

Function Add-TextBox() {
    Param (
        [System.Windows.Forms.Form]$Form,
        [string]$Placeholder = "",
        [System.Windows.Forms.Control]$AfterControl = $null,
        [int]$Padding = 0
    )

    $control = Add-Control -Form $Form -ControlType "TextBox" -AfterControl $AfterControl -Padding $Padding

    $control.Add_GotFocus({
        if ($this.Text -eq $Placeholder) {
            $this.ForeColor = "Black"
            $this.Text = ""
        }
    }.GetNewClosure()) # Here...

    $control.Add_LostFocus({
        if ($this.Text -eq "") {
            $this.ForeColor = "Darkgray"
            $this.Text = $Placeholder
        }
    }.GetNewClosure()) # And here.

    return $control
}


$form = New-Object system.Windows.Forms.Form

$textbox = Add-TextBox -Form $form -Placeholder "(XXXXXX, npr. 012345)"

$form.ShowDialog()