Winform application Add data to list view after certain variable contains data

Question

Is it possible to add data to a listview after a certain variable contains data ?

I have a function, which gets info from ConfigMgr when I press on a button.

After I press on that button, some info will be stored in a variable called $Results. I want the winform listview to wait until the variable $Results contains data, and then load my function, that will add data to my listview - is that possible ?

It's working fine if I don't clear the variable $Results, and run the winform a second time, because then the variable $Results is not empty, by having$Form.Add_Shown( { $Form.Activate(); Results }) in my script

Is there an equivalent method to achieve what I want ?

This is my function:

Function Get-SKUNotExists {

#Get objects stored in $Results
$listview_NotExists_SKU_Results = $Results | Select-Object Name,ID



# Compile a list of the properties 
$listview_NotExists_SKU_Properties = $listview_NotExists_SKU_Results[0].psObject.Properties

# Create a column in the listView for each property
$listview_NotExists_SKU_Properties | ForEach-Object {
    $listview_NotExists_SKU.Columns.Add("$($_.Name)") 
}

# Looping through each object in the array, and add a row for each
ForEach ($listview_NotExists_SKU_Result in $listview_NotExists_SKU_Results) {

    # Create a listViewItem, and assign it it's first value
    $listview_NotExists_SKU_Item = New-Object System.Windows.Forms.ListViewItem($listview_NotExists_SKU_Result.Name)

    # For each properties, except for 'Id' that we've already used to create the ListViewItem,
    # find the column name, and extract the data for that property on the current object/Tasksequence
    $listview_NotExists_SKU_Result.psObject.Properties | Where-Object { $_.Name -ne "ID" } | ForEach-Object {
        $listview_NotExists_SKU_Item.SubItems.Add("$($listview_NotExists_SKU_Result.$($_.Name))") 
    }

    # Add the created listViewItem to the ListView control
    # (not adding 'Out-Null' at the end of the line will result in numbers outputred to the console)
    $listview_NotExists_SKU.items.Add($listview_NotExists_SKU_Item) 
}

# Resize all columns of the listView to fit their contents
$listview_NotExists_SKU.AutoResizeColumns("HeaderSize")

}

This is the button that generate data to $results:

# Adding another button control to Form
$button_whatif = New-Object System.Windows.Forms.Button
$button_whatif.Location = New-Object System.Drawing.Size(352, 954)
$button_whatif.Size = New-Object System.Drawing.Size(320, 32)
$button_whatif.TextAlign = "MiddleCenter"
$button_whatif.Text = “WhatIf”
$button_whatif.Add_Click( { $script:Results = Set-DynamicVariables -Manufacturer "$($listview_Vendor.SelectedItems)" -TSPackageID "$($ListView_Tasksequences.SelectedItems.SubItems[1].Text)" -WhatIf })
$Form.Controls.Add($button_whatif)

mklement0 · Accepted Answer · 2019-08-26T21:38:53.500

Simply call your list-populating function (Get-SKUNotExists) directly after assigning to $Results:

$button_whatif.Add_Click({ 
  $Results = Set-DynamicVariables -Manufacturer "$($listview_Vendor.SelectedItems)" -TSPackageID "$($ListView_Tasksequences.SelectedItems.SubItems[1].Text)" -WhatIf
  Get-SKUNotExists 
})

Note that I've removed the $scipt: scope specifier from $Results, since it is no longer needed, given that you're calling Get-SKUNotExists from the same scope, which means that the child scope that Get-SKUNotExists runs in implicitly sees it.

That said:

In general, if a value is directly available, it's more robust to pass it as a parameter (argument) rather than relying on PowerShell's dynamic scoping (where descendant scopes implicitly see variables from ancestral scopes, unless shadowed by local variables).
If values must be shared between multiple event handlers, storing them in the script scope ($script:...), or, more generally, the parent scope may be needed, after all - see this answer.

Winform application Add data to list view after certain variable contains data

1 Answers1