Understanding Commands in WPF: A Cleaner Alternative to Button Click Events

Many WPF developers start by using Button Click events for handling user actions. At first, this seems simple and straightforward. But very soon, the code-behind file becomes huge , and maintaining it turns into a challenge. One big problem arises: when the logic changes, the button does not enable or disable automatically , and testing button click logic becomes very difficult. So the big question is: Is there a better way to handle button actions in WPF? The answer is Commands . In this post, we’ll learn how to use Commands in WPF with a simple, practical example. We’ll cover: What a Command is How it works Why using Commands is better than Click events How buttons can automatically enable or disable based on conditions What is a Command in WPF? In WPF, a Command acts as a middle layer between the UI and your logic. Instead of the button directly calling a method, it triggers a Command , and the Command decides: What code should run Whether the button s...

How to Enable/Disable Button on Validation using DelegateCommand of Prism


 MainWindow.xaml

 <Window x:Class="Wpf.Views.MainWindow"
             xmlns="http://schemas.microsoft.com/winfx/2006/xaml/presentation"
             xmlns:x="http://schemas.microsoft.com/winfx/2006/xaml"
             xmlns:d="http://schemas.microsoft.com/expression/blend/2008"
             xmlns:mc="http://schemas.openxmlformats.org/markup-compatibility/2006"
             xmlns:local="clr-namespace:Wpf"
             mc:Ignorable="d">
     <Window.Resources>
         <ControlTemplate  x:Key="TextBoxErrorStyle">
             <StackPanel Orientation="Horizontal">
                 <AdornedElementPlaceholder x:Name="ErrorHolder" >
                     <Border BorderBrush="red" BorderThickness="1" />
                 </AdornedElementPlaceholder>
                 <TextBlock  Text="{Binding [0].ErrorContent}" VerticalAlignment="Center" HorizontalAlignment="Right" Foreground="Red"/>

             </StackPanel>
         </ControlTemplate>

     </Window.Resources>
     <StackPanel Orientation="Vertical" HorizontalAlignment="Left" >
         <TextBox Height="30" Width="200" Text="{Binding Text,Mode=TwoWay,NotifyOnValidationError=True,
                  ValidatesOnDataErrors=True,UpdateSourceTrigger=PropertyChanged}"
                  Validation.ErrorTemplate="{StaticResource TextBoxErrorStyle}" Margin="5" />
         <Button Content="Click Here" Command="{Binding ClickCommand}" Margin="10" Width="100"/>
     </StackPanel>
 </Window>


 MainWindow.xaml.cs

 public partial class MainWindow : Window
     {
       
         public MainWindow()
         {
             InitializeComponent();
             DataContext= new MainWindowViewModel();
         
         }
       
     }

MainWindowViewModel.cs


 using Prism.Commands;
 using Prism.Mvvm;

 public class MainWindowViewModel : BindableBase, IDataErrorInfo
     {
         private string _text = string.Empty;

         public string Text
         {
             get
             {
                 return _text;
             }
             set
             {
                 SetProperty(ref _text, value);
                 ClickCommand.RaiseCanExecuteChanged();

             }
         }
       
         public string Error => string.Empty;

         public string this[string columnName]
         {
             get
             {

                 if (columnName == "Text")
                 {
                     if (string.IsNullOrEmpty(Text?.Trim()))
                         return "Text should not be empty";
                 }
                 return string.Empty;
             }

         }
       
         private DelegateCommand _clickCommand;
       
         public DelegateCommand ClickCommand
         {
             get
             {
                 return _clickCommand = _clickCommand ?? new DelegateCommand(Click, () => !string.IsNullOrEmpty(_text));
             }

         }
       
         private void Click()
         {
             //code
         }
     }

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