/V4/Quickstarts/MVVM/MVVM/ViewModels/OpenQuestionViewModel.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.ComponentModel;

using MVVM.Model;



namespace MVVM.ViewModels

{

    public class OpenQuestionViewModel : QuestionViewModel<OpenQuestion>

    {

        public OpenQuestionViewModel(OpenQuestion question)

            : base(question)

        {

        }



        public int AvailableLength

        {

            get

            {

                return this.Question.MaxLength - (this.Question.Response ?? string.Empty).Length;

            }

        }



        protected override void OnQuestionPropertyChanged(object sender, PropertyChangedEventArgs e)

        {

            if (e.PropertyName == "Response")

            {

                this.RaisePropertyChanged(() => this.AvailableLength);

                this.OnResponseChanged();

            }

        }

    }

}