Powershell Windows Form Multilevel Combo Box

问题

I have a windows form built in powershell thats designed to give 3 comboboxes:

CB1: Displays 5 Job descriptions

CB2: When any option from CB1 is selected its matched using $ComboBox1_SelectedIndexChanged and then a switch statement

CB3: When any option from CB2 is selected its matched using $ComboBox2_SelectedIndexChanged and then a switch statement

In this image, i have selected "Commercial Directorate" and its showing me the first match in the list "branch property trusts"

enter image description here

The issue with this is 2 fold.

1. i dont want it to show anything in this second combo box until i select one (stops users assuming defaults)

2. I have to click off the result and then back on it to have it display a result in the final combo box, in this example it shows "Result 1,2,3 correctly".

example

Further questions:

1. i cant use the sort property on the combobox as its referencing a datasource, can i sort the data another way ? (A-Z)

2. If i populate all 3 boxes, can i get the form to reset the 2nd and 3rd combo boxes to blank if i select a different option in CBO1? (essentially reset form)

     $initialForm = New-Object System.Windows.Forms.Form
   $initialForm.Size = New-Object System.Drawing.Size(300,300)
   
   $descriptions = @("Select Item","Commercial Directorate","DG Directorate","Financial Directorate","Fundraising Directorate","HR Directorate")
   
   $ComboBox1_SelectedIndexChanged=
       {
           Switch ($comboBox1.text)
          {
               "Commercial Directorate"
               {
                   $envnames = @("Branch Property Trusts Programme")
               }
               "DG Directorate"
               {
                   $envnames = @("Director General","Governance & Administration")
               }
   
               default
               {
                   $envnames = @()
               }
           }
   $comboBox2.Remove_SelectedIndexChanged($ComboBox2_SelectedIndexChanged)
   $comboBox2.DataSource = $envnames
   $ComboBox2.add_SelectedIndexChanged($ComboBox2_SelectedIndexChanged)
       }
   
   
   $ComboBox2_SelectedIndexChanged=
       {
           Switch ($comboBox2.text)
          {
               "Branch Property Trusts Programme"
               {
                   $envnames2 = @("Result1","Result2","Result3")
               }
               "Director General"
               {
                   $envnames2 = @("Result4","Result5")
               }
   
               default
               {
                   $envnames2 = @()
               }
           }
   $comboBox3.Remove_SelectedIndexChanged($ComboBox2_SelectedIndexChanged)
   $comboBox3.DataSource = $envnames2
   $ComboBox3.add_SelectedIndexChanged($ComboBox2_SelectedIndexChanged)
       }
   
   
   
   
   
   $comboBox1 = New-Object System.Windows.Forms.ComboBox
   $comboBox1.Location = New-Object System.Drawing.Point(25, 90)
   $comboBox1.Size = New-Object System.Drawing.Size(180, 20)
   $comboBox1.DataSource = $descriptions
   $ComboBox1.add_SelectedIndexChanged($ComboBox1_SelectedIndexChanged)
   
   $comboBox2 = New-Object System.Windows.Forms.ComboBox
   $comboBox2.Location = New-Object System.Drawing.Point(25, 120)
   $comboBox2.Size = New-Object System.Drawing.Size(180, 20)
   $ComboBox2.add_SelectedIndexChanged($ComboBox2_SelectedIndexChanged)
   
   $comboBox3 = New-Object System.Windows.Forms.ComboBox
   $comboBox3.Location = New-Object System.Drawing.Point(25, 150)
   $comboBox3.Size = New-Object System.Drawing.Size(180, 20)
   
   
   $initialForm.Controls.Add($comboBox1)
   $initialForm.Controls.Add($comboBox2)
   $initialForm.Controls.Add($comboBox3)
   $initialForm.ShowDialog()  
   

回答1:

1. After setting the Datasource you can do:

   $combobox2.Text=""
   

2. 1. solves this problem too

Further questions:

1. You can just sort your datasource like this:

   $envnames = $envnames | sort
   

   This has to be done after assigning the values to the variable but before setting it as a datasource for your combobox.

2. To reset your other Comboboxes you could just set the Datasource to an empty array at the beginning of your $combobox1_selectedindexchanged block:

   $ComboBox1_SelectedIndexChanged=
   {
       $comboBox2.DataSource=@()
       $combobox2.Text = ""
       $combobox3.DataSource=@()
       $combobox3.Text = ""
   ....
   }
   

Note that i dont work with windows forms so thats just what i hacked together in 2 minutes, might not be the optimal solution

来源：https://stackoverflow.com/questions/36329829/powershell-windows-form-multilevel-combo-box