silverlight mvvm sample

delegateCommand.cs:

using System;
using System.Net;
using System.Windows;
using System.Windows.Controls;
using System.Windows.Documents;
using System.Windows.Ink;
using System.Windows.Input;
using System.Windows.Media;
using System.Windows.Media.Animation;
using System.Windows.Shapes;
namespace SelfPro.Practice.SilverlightTest1.Common
{
 
     public class DelegateCommand : ICommand
    {
        private readonly Func<bool> _canExecute;
        private readonly Action _execute;
        public event EventHandler CanExecuteChanged;
        public DelegateCommand(Action execute)
            : this(execute,null)
        {
        }
        public DelegateCommand(Action execute,Func<bool> canExecute)
        {
            _execute = execute;
            _canExecute = canExecute;
        }
        public bool CanExecute(object o)
        {
            if (_canExecute == null)
            {
                return true;
            }
            return _canExecute();
        }
        public void Execute(object o)
        {
            _execute();
        }
        public void RaiseCanExecuteChanged()
        {
            if (CanExecuteChanged != null)
            {
                CanExecuteChanged(this,EventArgs.Empty);
            }
        }
    }
}

NotificationObject.cs:

 

using System;
using System.Net;
using System.Windows;
using System.Windows.Controls;
using System.Windows.Documents;
using System.Windows.Ink;
using System.Windows.Input;
using System.Windows.Media;
using System.Windows.Media.Animation;
using System.Windows.Shapes;
using System.ComponentModel;
namespace SelfPro.Practice.SilverlightTest1.Common
{
    public abstract class NotificationObject : INotifyPropertyChanged
    {
        public event PropertyChangedEventHandler PropertyChanged;
        protected virtual void RaisePropertyChanged(string propertyName)
        {
            PropertyChangedEventHandler handler = this.PropertyChanged;
            if (handler != null)
            {
                handler(this,new PropertyChangedEventArgs(propertyName));
            }
        }
        protected void RaisePropertyChanged(params string[] propertyNames)
        {
            if (propertyNames == null) throw new ArgumentNullException("propertyNames");
            foreach (var name in propertyNames)
            {
                this.RaisePropertyChanged(name);
            }
        }

    }
}

binding helper.cs:

using System;
using System.Net;
using System.Windows;
using System.Windows.Controls;
using System.Windows.Documents;
using System.Windows.Ink;
using System.Windows.Input;
using System.Windows.Media;
using System.Windows.Media.Animation;
using System.Windows.Shapes;
namespace SelfPro.Practice.SilverlightTest1.Common
{
    public class BindingHelper
    {
        public static bool GetUpdateSourceOnChange
          (DependencyObject obj)
        {
            return (bool)obj.GetValue(UpdateSourceOnChangeProperty);
        }
        public static void SetUpdateSourceOnChange
          (DependencyObject obj,bool value)
        {
            obj.SetValue(UpdateSourceOnChangeProperty,value);
        }
        // Using a DependencyProperty as the backing store for …
        public static readonly DependencyProperty
          UpdateSourceOnChangeProperty =
            DependencyProperty.Registerattached(
            "UpdateSourceOnChange",typeof(bool),typeof(BindingHelper),new PropertyMetadata(false,OnPropertyChanged));
        public static void OnPropertyChanged
          (DependencyObject obj,DependencyPropertyChangedEventArgs e)
        {
            var txt = obj as TextBox;
            if (txt == null)
                return;
            if ((bool)e.NewValue)
            {
                txt.TextChanged += OnTextChanged;
            }
            else
            {
                txt.TextChanged -= OnTextChanged;
            }
        }
       public static void OnTextChanged(object sender,TextChangedEventArgs e)
        {
            var txt = sender as TextBox;
            if (txt == null)
                return;
            var be = txt.GetBindingExpression(TextBox.TextProperty);
            if (be != null)
            {
                be.UpdateSource();
            }
        }
    }
}

mainwindowviewmodel.cs:

 

using System;
using System.Net;
using System.Windows;
using System.Windows.Controls;
using System.Windows.Documents;
using System.Windows.Ink;
using System.Windows.Input;
using System.Windows.Media;
using System.Windows.Media.Animation;
using System.Windows.Shapes;
using SelfPro.Practice.SilverlightTest1.Common;
namespace SelfPro.Practice.SilverlightTest1.viewmodel
{
    public class MainPageviewmodel:NotificationObject
    {
        private string inputStr;
        public string InputStr
        {
            get { return inputStr; }
            set 
            {
                inputStr = value;
                RaisePropertyChanged("InputStr");
            }
        }
        public DelegateCommand CmdRun
        {
            get;
            private set;
        }
        public MainPageviewmodel()
        {
            CmdRun = new DelegateCommand(new Action(Run),new Func<bool>(CanRun));
            this.PropertyChanged += (s,e) => { CmdRun.RaiseCanExecuteChanged(); };
        }
        private void Run()
        {
            InputStr = "aaa";
        }
        private bool CanRun()
        {
            if (string.IsNullOrEmpty(inputStr))
                return false;
            return inputStr.Equals("aaaaa");
        }
 
  
    }
}

mainwindow.xaml:

<UserControl x:Class="SelfPro.Practice.SilverlightTest1.MainPage"
    xmlns="http://schemas.microsoft.com/winfx/2006/xaml/presentation"
    xmlns:x="http://schemas.microsoft.com/winfx/2006/xaml"
    xmlns:vm="clr-namespace:SelfPro.Practice.SilverlightTest1.viewmodel"
    xmlns:cm="clr-namespace:SelfPro.Practice.SilverlightTest1.Common"
    xmlns:vsm="clr-namespace:System.Windows;assembly=System.Windows"
    xmlns:d="http://schemas.microsoft.com/expression/blend/2008"
    xmlns:mc="http://schemas.openxmlformats.org/markup-compatibility/2006"
    mc:Ignorable="d"
    d:DesignHeight="300" d:DesignWidth="400"
    xmlns:toolkit="http://schemas.microsoft.com/winfx/2006/xaml/presentation/toolkit"
             >
    <UserControl.DataContext>
        <vm:MainPageviewmodel></vm:MainPageviewmodel>
    </UserControl.DataContext>
    <UserControl.Resources>
        <Style targettype="Button">
            <Setter Property="Background" Value="SkyBlue" />
            <Setter Property="Width" Value="80" />
            <Setter Property="Height" Value="24" />
        </Style>
    </UserControl.Resources>
    <Border BorderThickness="2" Margin="10" CornerRadius="10" Height="200">
        <Border.Background>
            <LinearGradientBrush>
                <GradientStop Color="Green" Offset="0" />
                <GradientStop Color="Wheat" Offset="1" />
            </LinearGradientBrush>
        </Border.Background>
        <Border.BorderBrush>
            <LinearGradientBrush>
                <GradientStop Color="SkyBlue" Offset="1" />
                <GradientStop Color="SkyBlue" Offset="0" />
            </LinearGradientBrush>
        </Border.BorderBrush>
        <StackPanel>
            <Button Width="100" Height="25" Content="click me" Command="{Binding CmdRun}" />
            <TextBox Text="{Binding InputStr,Mode=TwoWay}" Width="200" cm:BindingHelper.UpdateSourceOnChange="True" />
        </StackPanel>
    </Border>
 
 
</UserControl>