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by dkt

Windows Forms is a Maintenance Risk

People say that WPF is a pretty big change from the Windows Forms technology of yesteryear, but there are also people who have invested considerable time and money into Windows Forms solutions that aren’t eager to rewrite their apps yet again. I can understand that—it takes time to develop things, and rewriting things for the sake of using the latest and greatest is not usually something that keeps projects on time and on budget.

But any new development should definitely be written in WPF.

Here’s a snippet of Windows Forms code that keeps a TextBox on the screen synchronized with a Quantity field on an Order object:

MyEditor.cs 
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public class MyEditor : UserControl
{
    private System.Windows.Forms.TextBox quantityTextBox;
 
    public MyEditor()
    {
        InitializeComponent();
    }
 
    private void InitializeComponent()
    {
        quantityTextBox = new System.Windows.Forms.TextBox();
        quantityTextBox.TextChanged += new System.EventHandler(quantityTextBox_TextChanged);
        // ...more auto-generated noise
    }
 
    public void SetOrder(Order order)
    {
        _order = order;
        _order.PropertyChanged += order_PropertyChanged;
        quantityTextBox.Text = _order.Quantity.ToString();
    }
 
    private void quantityTextBox_TextChanged(object sender, EventArgs e)
    {
        long qty;
        if (long.TryParse(quantityTextBox.Text, out qty))
        {
            _order.Quantity = qty;
            quantityTextBox.BackColor = Color.White;
        }
        else
        {
            quantityTextBox.BackColor = Color.Pink;
        }
    }
 
    private void order_PropertyChanged(object sender, PropertyChangedEventArgs e)
    {
        if (e.PropertyName == "Quantity")
        {
            quantityTextBox.Text = _order.Quantity.ToString();
        }
    }
}

And in WPF:

MyEditor.xaml 
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<UserControl x:Class="MyEditor"
                         xmlns="http://schemas.microsoft.com/winfx/2006/xaml/presentation"
                         xmlns:x="http://schemas.microsoft.com/winfx/2006/xaml">
    <TextBox Text="{Binding Path=Quantity}"/>
</UserControl>
MyEditor.xaml.cs 
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public partial class MyEditor
{
    public MyEditor()
    {
        InitializeComponent();
    }
 
    public void SetOrder(Order order)
    {
        this.DataContext = order;
    }
}

Which one would you rather maintain? —DKT