我需要得到作为变量存储的第一个下拉框的结果，并用它代替第二个下拉框中的示例名称。
基本上，第二个框中的select查询需要针对slq\u示例中的主数据库运行，一旦做出选择，第一个下拉框就会生成这个slq\u示例。
我试过几种不同的方法，但似乎都做不好。有什么建议吗？
提前谢谢！

# first DROPDOWN Box

$label = New-Object System.Windows.Forms.Label
$label.Location = New-Object System.Drawing.Point(10,20)
$label.Size = New-Object System.Drawing.Size(280,20)
$label.Text = 'SQL Server Name'
$form.Controls.Add($label)
$DropDownBox = New-Object System.Windows.Forms.ComboBox
$DropDownBox.Location = New-Object System.Drawing.Size(10,40)
$DropDownBox.Size = New-Object System.Drawing.Size(260,20)
$DropDownBox.DropDownHeight = 200
$Form.Controls.Add($DropDownBox)
$wksList= invoke-sqlcmd -query "select * from VIEW_NAME
order by instance_name" -database DATABASE_NAME -serverinstance INSTANCE_NAME
foreach ($wks in $wksList) {
                      $DropDownBox.Items.Add($wks.Instance_Name)
                              } #end foreach

# end first DROPDOWN box

# second DROPDOWN Box

$label2 = New-Object System.Windows.Forms.Label
$label2.Location = New-Object System.Drawing.Point(10,90)
$label2.Size = New-Object System.Drawing.Size(280,20)
$label2.Text = 'Database Name'
$form.Controls.Add($label2)
$DropDownBox2 = New-Object System.Windows.Forms.ComboBox
$DropDownBox2.Location = New-Object System.Drawing.Size(10,110)
$DropDownBox2.Size = New-Object System.Drawing.Size(260,20)
$DropDownBox2.DropDownHeight = 200
$Form.Controls.Add($DropDownBox2)
$wksList2= invoke-sqlcmd -query "select name from sys.databases
where database_id>4
order by name" -database MASTER -serverinstance INSTANCE_NAME
foreach ($wks in $wksList2) {
                     $DropDownBox2.Items.Add($wks.name)
                            } #end foreach

# end second DROPDOWN box

试图在下面发布当前代码….把编辑搞砸了：-（，包括jonathan建议的更改。。。将不得不开始新的职位…..抱歉！！！！！！！！！！！！
正如我在给jonathan的评论中提到的，这似乎是对的，但是传递给-serverinstance的任何值似乎都不起作用。它“尝试”连接，但powershell生成一个错误，说明它无法连接到服务器。
附加说明-通过添加get variable命令，我确定传递给instancename的值实际上是空的。
99.9%。。。有什么想法吗？再次提前感谢。
通过将$instancename=$dropdownbox.selecteditem命令移动到第二个下拉框下，流程的aprt现在似乎可以正常工作。我从第一个下拉列表中选择一个服务器，单击按钮，然后将正确的数据库列表填充到第二个下拉列表中。
但是，现在进程底部的$dbname=$dropdownbox2.text语句失败，为db name提供了一个空值。因此，没有备份。
还在玩变奏曲，但如果有人看到我错过了什么，告诉我。
我假设我需要添加第二个按钮并单击action，以将box 2的结果设置为db变量，但是我在放置方面遇到了问题。
是的，…代码输入正确。。。。
这是一个似乎可行的版本，除了将第二个组合框中的值向下传递到底部的$dbname。。。。。

Add-Type -AssemblyName System.Windows.Forms
Add-Type -AssemblyName System.Drawing
Add-Type -AssemblyName Microsoft.VisualBasic

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

$image = [System.Drawing.Image]::Fromfile('Path to image')    
$pictureBox = new-object Windows.Forms.PictureBox  #--instantiates a PictureBox
$pictureBox.width=420
$pictureBox.height=420
$pictureBox.top=20
$pictureBox.left=350
$pictureBox.Image=$image

# $form.Font = New-Object System.Drawing.Font("Lucida Console",11,[System.Drawing.FontStyle]::Regular)

$form = New-Object System.Windows.Forms.Form
$form.Text = 'MSSQL DATABASE BACKUP UTILITY'
$form.Size = New-Object System.Drawing.Size(800,500)
$form.Font = New-Object System.Drawing.Font("Times New Roman",11,[System.Drawing.FontStyle]::Regular)
$form.StartPosition = 'CenterScreen'
$form.Controls.add($pictureBox)

$okButton = New-Object System.Windows.Forms.Button
$okButton.Location = New-Object System.Drawing.Point(10,400)
$okButton.Size = New-Object System.Drawing.Size(75,23)
$okButton.Text = 'OK'
$okButton.DialogResult = [System.Windows.Forms.DialogResult]::OK
$form.AcceptButton = $okButton
$form.Controls.Add($okButton)

# first DROPDOWN Box

$label = New-Object System.Windows.Forms.Label
$label.Location = New-Object System.Drawing.Point(10,20)
$label.Size = New-Object System.Drawing.Size(280,20)
$label.Text = 'SQL Instance Name'
$form.Controls.Add($label)

$DropDownBox = New-Object System.Windows.Forms.ComboBox
$DropDownBox.Location = New-Object System.Drawing.Size(10,40)
$DropDownBox.Size = New-Object System.Drawing.Size(260,20)
$DropDownBox.DropDownHeight = 200
$Form.Controls.Add($DropDownBox)

$wksList= invoke-sqlcmd -query "select * from VIEW NAME
    order by instance_name" -database DBA -serverinstance INSTANCE_NAME

foreach ($wks in $wksList)
    { $DropDownBox.Items.Add($wks.Instance_Name) }

$Button = New-Object System.Windows.Forms.Button
$Button.Location = New-Object System.Drawing.Size(10,80)
$Button.Size = New-Object System.Drawing.Size(120,23)
$Button.Text = "Set Instance"

$Form.Controls.Add($Button)

# Add Button event

 $Button.Add_Click(
{   
    #second DROPDOWN Box
    $InstanceName = $DropDownBox.SelectedItem
    $label2 = New-Object System.Windows.Forms.Label
    $label2.Location = New-Object System.Drawing.Point(10,120)
   $label2.Size = New-Object System.Drawing.Size(280,20)
    $label2.Text = 'Database Name'
    $form.Controls.Add($label2)

    $DropDownBox2 = New-Object System.Windows.Forms.ComboBox
    $DropDownBox2.Location = New-Object System.Drawing.Size(10,140)
    $DropDownBox2.Size = New-Object System.Drawing.Size(260,20)
    $DropDownBox2.DropDownHeight = 200
    $Form.Controls.Add($DropDownBox2)

    $wksList2= invoke-sqlcmd -query "select name from sys.databases
    where database_id>4
    order by name" -database MASTER -serverinstance $InstanceName

    foreach ($wks in $wksList2)
        { $DropDownBox2.Items.Add($wks.name) }

})

# end second DROPDOWN box

# third text box

$label3 = New-Object System.Windows.Forms.Label
$label3.Location = New-Object System.Drawing.Point(10,220)
$label3.Size = New-Object System.Drawing.Size(280,20)
$label3.Text = 'Desired Backup Location'
$form.Controls.Add($label3)

$textBox3 = New-Object System.Windows.Forms.TextBox
$textBox3.Location = New-Object System.Drawing.Point(10,240)
$textBox3.Size = New-Object System.Drawing.Size(260,20)
$form.Controls.Add($textBox3)

# end third text box

# fourth text box

$label4 = New-Object System.Windows.Forms.Label
$label4.Location = New-Object System.Drawing.Point(10,280)
$label4.Size = New-Object System.Drawing.Size(280,20)
$label4.Text = 'Desired Backup Name'
$form.Controls.Add($label4)

$textBox4 = New-Object System.Windows.Forms.TextBox
$textBox4.Location = New-Object System.Drawing.Point(10,300)
$textBox4.Size = New-Object System.Drawing.Size(260,20)
$form.Controls.Add($textBox4)

# end fourth text box

# fifth text box

$label5 = New-Object System.Windows.Forms.Label
$label5.Location = New-Object System.Drawing.Point(10,340)
$label5.Size = New-Object System.Drawing.Size(280,20)
$label5.Text = 'Your Email Address'
$form.Controls.Add($label5)

$textBox5 = New-Object System.Windows.Forms.TextBox
$textBox5.Location = New-Object System.Drawing.Point(10,360)
$textBox5.Size = New-Object System.Drawing.Size(260,20)
$form.Controls.Add($textBox5)

# end fifth text box

$form.Topmost = $true

$form.Add_Shown({$DropDownBox.Select()})
$result = $form.ShowDialog()

if ($result -eq [System.Windows.Forms.DialogResult]::OK)
{
$Server = $DropDownBox.text
$DBName = $DropDownBox2.text
$SharedFolder = $textBox3.text
$BUName = $textBox4.text
$mail = $textBox5.text

Get-Variable

   <#$Date = Get-Date -format yyyyMMdd#>
Backup-SqlDatabase  -ServerInstance $server `
                    -Database $DBName `
                    -CopyOnly `
                    -CompressionOption on `
                    -BackupFile "$($SharedFolder)\$DBName-$BUName.bak" `
                    -BackupAction Database `
                    -checksum

# SMPT Section

$From = "SUPPORT EMAIL"
$To = $mail
$Subject = "RECENT MSSQL BACKUP REQUEST"
$Body = "Your MSSQL database backup from $server, $DBName, has been backed up to $SharedFolder. Please check the directory path you specified for your backup. If you have any problems, fwd this email to SUPPORT EMAIL for assistance."
$PSEmailServer = "SMTP SERVER"

Send-MailMessage -From $From -To $To -Subject $Subject -Body $Body -SmtpServer $PSEmailserver