点击按钮更新PowerShell WinForm的DataGridView数据不生效问题咨询

• 变量作用域问题：PowerShell函数内默认定义的是局部变量，你在AddClient函数内直接给$tableData、$dataGridView赋值，修改的是函数内的局部变量，并不会影响界面上绑定的全局控件和数据源
• 错误重新实例化控件：你在刷新逻辑中重新创建了DataGridView实例，但没有将新实例添加到窗体控件集合中，界面始终显示的是初始化时创建的旧控件，变更自然不会呈现
• 数据源更新不符合WinForm绑定规范：直接替换数据源变量不会触发控件自动刷新，需要主动重置控件的DataSource属性
• 原有代码存在变量拼写错误：逻辑分支中使用了未定义的$Usernames变量，会导致新增逻辑异常

Add-Type -AssemblyName System.Windows.Forms
Add-Type -AssemblyName System.Data
Add-Type -AssemblyName System.Collections

$jsonDB = Get-Content 'C:\Support\HardwareCollection.json' -Raw | ConvertFrom-Json
$script:tableData = New-Object System.Collections.ArrayList
$tableData.AddRange($jsonDB)

$Form = New-Object System.Windows.Forms.Form 
$Form.Size = New-Object System.Drawing.Size(1050, 425) 
$Form.MaximizeBox = $False 
$Form.StartPosition = "CenterScreen" 
$Form.FormBorderStyle = 'Fixed3D' 
$Form.Text = "Hardware Collection"

$AddClientNButton = new-object System.Windows.Forms.Button
$AddClientNButton.Location = new-object system.drawing.size(61,90) 
$AddClientNButton.Size = new-object system.drawing.size(80,50)
$AddClientNButton.Text = "Add Client"
$AddClientNButton.Add_Click({AddClient}) 
$AddClientNButton.TabIndex = 10
$Form.Controls.Add($AddClientNButton)

$UserNametextBox = New-Object System.Windows.Forms.TextBox
$UserNametextBox.Location = New-Object System.Drawing.Point(1,1)
$UserNametextBox.Size = New-Object System.Drawing.Size(300,20)
$UserNametextBox.text="User Name"
$UserNametextBox.MaxLength = 6
$UserNametextBox.Add_Click({$this.SelectAll(); $this.Focus()})
$UserNametextBox.TabIndex = 0
$form.Controls.Add($UserNametextBox)

$script:dataGridView = New-Object System.Windows.Forms.DataGridView -Property @{
    Size = New-Object System.Drawing.Size(500, 200)
    Location = New-Object System.Drawing.Size(1, 150)
    ColumnHeadersVisible = $True
    DataSource = $tableData
    AutoSizeColumnsMode = 'AllCells'
    ColumnHeadersHeightSizeMode = 'AutoSize'
}

function AddClient
{
    $jsonDB = Get-Content 'C:\Support\HardwareCollection.json' -Raw | ConvertFrom-Json
    $Date = Get-Date -Format "MM/dd/yyyy HH:mm:ss K" 
    $Username = $UserNametextBox.text.Trim()

    if ([string]::IsNullOrEmpty($Username)) {
        return
    }

    $NewEntryItems = $null
    if($null -eq $jsonDB.username)
    {
        $NewEntryItems = $Username
    }
    else
    {
        if($jsonDB.username -notcontains $Username)
        {
            $NewEntryItems = $Username
        }
    }

    if ($null -ne $NewEntryItems) {
        $CollectionData = New-Object PSObject -Property @{
            Username = $Username
            Date = $Date
        }
        $jsonDB += $CollectionData
        $jsonDB | ConvertTo-Json -Compress | Set-Content 'C:\Support\HardwareCollection.json'
    }
    
    # 刷新DataGridView逻辑
    $newJson = Get-Content 'C:\Support\HardwareCollection.json' -Raw | ConvertFrom-Json
    $script:tableData.Clear()
    $script:tableData.AddRange($newJson)
    # 重置数据源触发刷新
    $script:dataGridView.DataSource = $null
    $script:dataGridView.DataSource = $script:tableData
}

$Form.Controls.Add($dataGridView)  
$Form.ShowDialog()

• 给全局使用的$tableData、$dataGridView添加script:作用域前缀，确保函数内可以修改到全局对象
• 删除了函数中重新实例化DataGridView的冗余逻辑，直接修改原有控件的数据源
• 修复了未定义变量的逻辑错误，新增了空值校验避免无效提交
• 刷新时先将数据源置空再重新赋值，强制触发DataGridView的界面刷新

内容的提问来源于stack exchange，提问作者Listor