/V2/trunk/RI/Desktop/StockTraderRI.Infrastructure/Behaviors/ReturnCommandBehavior.cs

//===================================================================================

// Microsoft patterns & practices

// Composite Application Guidance for Windows Presentation Foundation and Silverlight

//===================================================================================

// Copyright (c) Microsoft Corporation.  All rights reserved.

// THIS CODE AND INFORMATION IS PROVIDED "AS IS" WITHOUT WARRANTY

// OF ANY KIND, EITHER EXPRESSED OR IMPLIED, INCLUDING BUT NOT

// LIMITED TO THE IMPLIED WARRANTIES OF MERCHANTABILITY AND

// FITNESS FOR A PARTICULAR PURPOSE.

//===================================================================================

// The example companies, organizations, products, domain names,

// e-mail addresses, logos, people, places, and events depicted

// herein are fictitious.  No association with any real company,

// organization, product, domain name, email address, logo, person,

// places, or events is intended or should be inferred.

//===================================================================================

using System.Windows.Controls;

using System.Windows.Input;

using Microsoft.Practices.Composite.Presentation.Commands;



namespace StockTraderRI.Infrastructure.Behaviors

{

    /// <summary>

    /// Defines a behavior that executes a <see cref="ICommand"/> when the Return key is pressed inside a <see cref="TextBox"/>.

    /// </summary>

    /// <remarks>This behavior also supports setting a basic watermark on the <see cref="TextBox"/>.</remarks>

    public class ReturnCommandBehavior : CommandBehaviorBase<TextBox>

    {

        /// <summary>

        /// Initializes a new instance of <see cref="ReturnCommandBehavior"/>.

        /// </summary>

        /// <param name="textBox">The <see cref="TextBox"/> over which the <see cref="ICommand"/> will work.</param>

        public ReturnCommandBehavior(TextBox textBox)

            : base(textBox)

        {

            textBox.AcceptsReturn = false;

            textBox.KeyDown += (s, e) => this.KeyPressed(e.Key);

            textBox.GotFocus += (s, e) => this.GotFocus();

            textBox.LostFocus += (s, e) => this.LostFocus();

        }



        /// <summary>

        /// Gets or Sets the text which is set as water mark on the <see cref="TextBox"/>.

        /// </summary>

        public string DefaultTextAfterCommandExecution { get; set; }



        /// <summary>

        /// Executes the <see cref="ICommand"/> when <paramref name="key"/> is <see cref="Key.Enter"/>.

        /// </summary>

        /// <param name="key">The key pressed on the <see cref="TextBox"/>.</param>

        protected void KeyPressed(Key key)

        {

            if (key == Key.Enter && TargetObject != null)

            {

                this.CommandParameter = TargetObject.Text;

                ExecuteCommand();



                this.ResetText();

            }

        }



        private void GotFocus()

        {

            if (TargetObject != null && TargetObject.Text == this.DefaultTextAfterCommandExecution)

            {

                this.ResetText();

            }

        }



        private void ResetText()

        {

            TargetObject.Text = string.Empty;

        }



        private void LostFocus()

        {

            if (TargetObject != null && string.IsNullOrEmpty(TargetObject.Text) && this.DefaultTextAfterCommandExecution != null)

            {

                TargetObject.Text = this.DefaultTextAfterCommandExecution;

            }

        }

    }

}