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WPF/MVVM Quick Start Tutorial

, 10 Oct 2012
A quick example of MVVM in WPF
MvvmExample.zip
MvvmExample
Example1
Properties
Settings.settings
Example2
Properties
Settings.settings
Example3
Properties
Settings.settings
Example4
Properties
Settings.settings
Example5
Properties
Settings.settings
Example6
Properties
Settings.settings
MicroMvvm
Properties
MvvmExample.suo
//  Original author - Josh Smith - http://msdn.microsoft.com/en-us/magazine/dd419663.aspx#id0090030

using System;
using System.Diagnostics;
using System.Windows.Input;

namespace MicroMvvm
{
    /// <summary>
    /// A command whose sole purpose is to relay its functionality to other objects by invoking delegates. The default return value for the CanExecute method is 'true'.
    /// </summary>
    public class RelayCommand<T> : ICommand
    {

        #region Declarations

        readonly Predicate<T> _canExecute;
        readonly Action<T> _execute;

        #endregion

        #region Constructors

        /// <summary>
        /// Initializes a new instance of the <see cref="RelayCommand&lt;T&gt;"/> class and the command can always be executed.
        /// </summary>
        /// <param name="execute">The execution logic.</param>
        public RelayCommand(Action<T> execute)
            : this(execute, null)
        {
        }

        /// <summary>
        /// Initializes a new instance of the <see cref="RelayCommand&lt;T&gt;"/> class.
        /// </summary>
        /// <param name="execute">The execution logic.</param>
        /// <param name="canExecute">The execution status logic.</param>
        public RelayCommand(Action<T> execute, Predicate<T> canExecute)
        {

            if (execute == null)
                throw new ArgumentNullException("execute");
            _execute = execute;
            _canExecute = canExecute;
        }

        #endregion

        #region ICommand Members

        public event EventHandler CanExecuteChanged
        {
            add
            {

                if (_canExecute != null)
                    CommandManager.RequerySuggested += value;
            }
            remove
            {

                if (_canExecute != null)
                    CommandManager.RequerySuggested -= value;
            }
        }

        [DebuggerStepThrough]
        public Boolean CanExecute(Object parameter)
        {
            return _canExecute == null ? true : _canExecute((T)parameter);
        }

        public void Execute(Object parameter)
        {
            _execute((T)parameter);
        }

        #endregion
    }

    /// <summary>
    /// A command whose sole purpose is to relay its functionality to other objects by invoking delegates. The default return value for the CanExecute method is 'true'.
    /// </summary>
    public class RelayCommand : ICommand
    {

        #region Declarations

        readonly Func<Boolean> _canExecute;
        readonly Action _execute;

        #endregion

        #region Constructors

        /// <summary>
        /// Initializes a new instance of the <see cref="RelayCommand&lt;T&gt;"/> class and the command can always be executed.
        /// </summary>
        /// <param name="execute">The execution logic.</param>
        public RelayCommand(Action execute)
            : this(execute, null)
        {
        }

        /// <summary>
        /// Initializes a new instance of the <see cref="RelayCommand&lt;T&gt;"/> class.
        /// </summary>
        /// <param name="execute">The execution logic.</param>
        /// <param name="canExecute">The execution status logic.</param>
        public RelayCommand(Action execute, Func<Boolean> canExecute)
        {

            if (execute == null)
                throw new ArgumentNullException("execute");
            _execute = execute;
            _canExecute = canExecute;
        }

        #endregion

        #region ICommand Members

        public event EventHandler CanExecuteChanged
        {
            add
            {

                if (_canExecute != null)
                    CommandManager.RequerySuggested += value;
            }
            remove
            {

                if (_canExecute != null)
                    CommandManager.RequerySuggested -= value;
            }
        }

        [DebuggerStepThrough]
        public Boolean CanExecute(Object parameter)
        {
            return _canExecute == null ? true : _canExecute();
        }

        public void Execute(Object parameter)
        {
            _execute();
        }

        #endregion
    }
}

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This article, along with any associated source code and files, is licensed under The Code Project Open License (CPOL)

About the Author

Barry Lapthorn

United Kingdom United Kingdom
Jack of all trades.

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