WPF - command via events

Question

I have handle the TextChanged event via Command.

<TextBox Text="{Binding ConnectionString, Mode=TwoWay}" xmlns:i="http://schemas.microsoft.com/expression/2010/interactivity">
                <i:Interaction.Triggers>
                    <i:EventTrigger EventName="TextChanged">
                        <i:InvokeCommandAction Command="{Binding Path=SomeCommand, Mode=OneWay}"/>
                    </i:EventTrigger>
                </i:Interaction.Triggers>
            </TextBox>

My references:

- Microsoft.Expression.Interactions
- Systsem.Windwos.Interactivity

Exception:

A first chance exception of type 'System.Windows.Markup.XamlParseException' occurred in PresentationFramework.dll

Additional information: Could not load file or assembly 'System.Windows.Interactivity, PublicKeyToken=31bf3856ad364e35' or one of its dependencies. The system cannot find the file specified.

Theodosius Von Richthofen · Answer 1 · 2014-12-05T14:14:30.043

Does this work for you?

XAML-

<Window x:Class="garbage.MainWindow"
    xmlns="http://schemas.microsoft.com/winfx/2006/xaml/presentation"
    xmlns:i="http://schemas.microsoft.com/expression/2010/interactivity"
    xmlns:x="http://schemas.microsoft.com/winfx/2006/xaml"
    Title="MainWindow" Height="350" Width="525">
<Grid>
    <TextBox Text="{Binding ConnectionString, Mode=TwoWay}" xmlns:i="clr-namespace:System.Windows.Interactivity;assembly=System.Windows.Interactivity">
        <i:Interaction.Triggers>
            <i:EventTrigger EventName="TextChanged">
                <i:InvokeCommandAction Command="{Binding Path=SomeCommand, Mode=OneWay}"/>
            </i:EventTrigger>
        </i:Interaction.Triggers>
    </TextBox>
</Grid>

Code behind

    using System;
using System.Collections.Generic;
using System.Linq;
using System.Text;
using System.Threading.Tasks;
using System.Windows;
using System.Windows.Controls;
using System.Windows.Data;
using System.Windows.Documents;
using System.Windows.Input;
using System.Windows.Media;
using System.Windows.Media.Imaging;
using System.Windows.Navigation;
using System.Windows.Shapes;

namespace garbage
{
    public partial class MainWindow : Window
    {
        public MainWindow()
        {
            InitializeComponent();
            DataContext = this;
            SomeCommand = new RelayCommand(SomeCommandExecute, CanExecute);
        }

        private ICommand someCommand;
        public ICommand SomeCommand
        {
            get
            {
                return someCommand;
            }
            set
            {
                someCommand = value;
            }
        }

        public void SomeCommandExecute(object something)
        {
            MessageBox.Show("Success");
        }

        private bool CanExecute(object thing)
        { return true; }

    }
}

RelayCommand.cs

    using System;
using System.Collections.Generic;
using System.Linq;
using System.Text;
using System.Threading.Tasks;
using System.Windows.Input;

namespace garbage
{
    public class RelayCommand : ICommand
    {
        private Action<object> execute;

        private Predicate<object> canExecute;

        private event EventHandler CanExecuteChangedInternal;

        public RelayCommand(Action<object> execute)
            : this(execute, DefaultCanExecute)
        {
        }

        public RelayCommand(Action<object> execute, Predicate<object> canExecute)
        {
            if (execute == null)
            {
                throw new ArgumentNullException("execute");
            }

            if (canExecute == null)
            {
                throw new ArgumentNullException("canExecute");
            }

            this.execute = execute;
            this.canExecute = canExecute;
        }

        public event EventHandler CanExecuteChanged
        {
            add
            {
                CommandManager.RequerySuggested += value;
                this.CanExecuteChangedInternal += value;
            }

            remove
            {
                CommandManager.RequerySuggested -= value;
                this.CanExecuteChangedInternal -= value;
            }
        }

        public bool CanExecute(object parameter)
        {
            return this.canExecute != null && this.canExecute(parameter);
        }

        public void Execute(object parameter)
        {
            this.execute(parameter);
        }

        public void OnCanExecuteChanged()
        {
            EventHandler handler = this.CanExecuteChangedInternal;
            if (handler != null)
            {
                //DispatcherHelper.BeginInvokeOnUIThread(() => handler.Invoke(this, EventArgs.Empty));
                handler.Invoke(this, EventArgs.Empty);
            }
        }

        public void Destroy()
        {
            this.canExecute = _ => false;
            this.execute = _ => { return; };
        }

        private static bool DefaultCanExecute(object parameter)
        {
            return true;
        }
    }
}

"'Expression.Blend.Sdk 1.0.2' already installed." TargetFramework: .NET framework 4.5 — WymyslonyNick, Dec 04 '14 at 13:47
check my edit, your xaml is incorrectly referencing it in the xmlns:i part — Theodosius Von Richthofen, Dec 04 '14 at 14:29
Is not working. 1 error: Error 1 Cannot add instance of type 'EventTrigger' to a collection of type 'TriggerCollection'. Only items of type 'T' are allowed. — WymyslonyNick, Dec 05 '14 at 07:28
see me edited answer. don't need any reference to Microsoft.Expression.Interactions. i used your original i: reference, in fact, either one works. i don't know if you're using RelayCommand or what, shouldn't matter. i don't see any errors about EventTrigger, so you must have something wrong. — Theodosius Von Richthofen, Dec 05 '14 at 14:16

WPF - command via events

1 Answers1