PowerShell: Understanding Windows Forms Data Binding

Technorati Tags: Powerhell Windows Forms

A simple example of a data bound form

I decided that it was time to post a cleaned up example of how to do data binding with PowerShell Forms.  I pulled up an old demo and set it up to use an XML extract from the NorthWind demo database.  For a demo I though that it would be better if the example could be run on any system so I have converted the form to load its data set from the XML extract.

In this post I will just point out the features and show a couple of images as well as a link to the code.

 

 

The form is intentionally simple and the colors were only changed to highlight the elements.

Features:

• ‘Select Customer” is a live search box that autocompletes against the dataset.  Code (cost 2 line)
  
• The two text box are populated with values from the selected grid row.  (code cosr one line per textbox)
  
• Top navigation bar actively moves through the data set with the buttons. (code cost 3 lines.

• Nav bar allows deleting and editing.  (code cost nothing)
  
• Double clicking launches edit form.  (code cost 1 line)

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• Edit Form doubles as a “new” record editor by adding one code line to the main form.
  
• Save and cancel for edits take about 4 lines.
  
• Main form detects data changes and prompts for saving.

Scripts:

The scripts are available in a Zip.  A Sapien PowerShell Studio Project is included and a PS1 file that runs without the project.
Three files are included for the forms in Demo-FormXmlDataBinding.zip

1. Demo-FormXmlDataBinding PSS folder
   
2. Standalone folder
   1. Demo-FormXmlDataBinding.ps1 –- the main file
      
   2. northwind.xml – the data set.
   
   
   
   
3. The project folder is included as Demo-FormXmlDataBinding
   1. PowerShell Studio project files

Download:

Demo-FormXmlDataBinding.zip

Small code footprint:

For all of its functionality the main form contains fewer than 50 lines of code

PowerShell active code:

# Set up the form objects and bind

$customerBindingSource = New-Object System.Windows.Forms.BindingSource

$nav = New-Object System.Windows.Forms.BindingNavigator($true)

$ds = New-Object System.Data.DataSet

# configure navigator$formXMLDataBindingExample.Controls.Add($nav)

$nav.BackColor = 'LightBlue'$nav.ShowItemToolTips = $true

$nav.Dock = 'top'$nav.BindingSource = $customerBindingSource

$formXMLDataBindingExample_Load={
    
    # We are loading only one table.  It is  possible to 
    # load many related tables as a relationship and they
    # will all be synchronized
    $ds.ReadXml($northwindXml)

    # We can set events on the dataset
    $ds.Tables['Customer'].add_RowChanged({ $script:modified = $true;Write-Host 'Row Changed' })
    
    # Assign the DataSet as the DataSource for the BindingSource.
    $customerBindingSource.DataSource = $ds.Tables["Customer"]
    
    # Bind to the controls.
    $textboxContactName.DataBindings.Add((New-Object System.Windows.Forms.Binding('Text', $customerBindingSource, 'ContactName', $true)))
    $textboxPhone.DataBindings.Add((New-Object System.Windows.Forms.Binding('Text', $customerBindingSource, 'Phone', $true)))
    $dgvCustomerTable.DataSource = $customerBindingSource
    $cbCompany.DataSource = $customerBindingSource
    $cbCompany.DisplayMember = 'CompanyName'
}


$dgvCustomerTable_MouseDoubleClick=[System.Windows.Forms.MouseEventHandler]{
    
    # show child form with current row data
    Show-DataChild_psf ([System.Data.DataRowView]$customerBindingSource.Current)
}

$formXMLDataBindingExample_FormClosing=[System.Windows.Forms.FormClosingEventHandler]{
    
    if($modified){
        $answer = [System.Windows.Forms.MessageBox]::Show('Do you want to save your changes and close this form?','Data has changed','YesNoCancel')
        $_.Cancel = switch ($answer){
            Yes {$ds.AcceptChanges()}
            No {$false}
            Cancel {$true}
        }
    }
    
}

Code discussion:

I will post a second and maybe third blog with a more detailed discussion of how this code works and how data binding works in Windows Forms.  Grab the RSS/Atom link and stay tuned for more.

Posts in this article:

PowerShell: Understanding Windows Forms Data Binding
PowerShell:Understanding Windows Forms Data Binding 2

Extra
Binding SQlServer Data to WinForms with PowerShell