WPF >MVVM Basic quick start tutorial C#
In MVVM (Model-View-ViewModel)
- model knows nothing
- view model knows only about model
- view knows only about view model
Project structure
Project.cs
using System.ComponentModel;
namespace MVVM
{
public class Project : INotifyPropertyChanged
{
private string projectCode;
private string projectDescription;
public string ProjectCode
{
get
{
return projectCode;
}
set
{
projectCode = value;
OnPropertyChanged("ProjectCode");
}
}
public string ProjectDescription
{
get
{
return projectDescription;
}
set
{
projectDescription = value;
OnPropertyChanged("ProjectDescription");
}
}
#region
INotifyPropertyChanged Members
public event PropertyChangedEventHandler PropertyChanged;
private void OnPropertyChanged(string propertyName)
{
if (PropertyChanged != null)
{
PropertyChanged(this, new PropertyChangedEventArgs(propertyName));
}
}
#endregion
}
}
Projects.xaml
<Window x:Name="ProjectsWindow" x:Class="MVVM.View.Projects"
xmlns="http://schemas.microsoft.com/winfx/2006/xaml/presentation"
xmlns:x="http://schemas.microsoft.com/winfx/2006/xaml"
Title="Projects" Height="300" Width="300" Loaded="ProjectsWindow_Loaded">
<Grid>
<Grid.RowDefinitions>
<RowDefinition Height="Auto"/>
<RowDefinition Height="*"/>
<RowDefinition Height="Auto"/>
</Grid.RowDefinitions>
<Button Content="Save" Grid.Row="0" HorizontalAlignment="Left" Name="btnUpdate"
VerticalAlignment="Top"
Command="{Binding Path=SaveCommand}" />
<ListView Name="ProjectList"
Grid.Row="1" ItemsSource="{Binding Projects}" >
<ListView.View>
<GridView x:Name="grdProject">
<GridViewColumn Header="Code" DisplayMemberBinding="{Binding ProjectCode}" Width="Auto" />
<GridViewColumn Header="Description" DisplayMemberBinding="{Binding ProjectDescription}" Width="Auto" />
</GridView>
</ListView.View>
</ListView>
</Grid>
</Window>
Projects.xaml.cs
using System.Windows;
namespace MVVM.View
{
/// <summary>
/// Interaction logic for Projects.xaml
/// </summary>
public partial class Projects : Window
{
public Projects()
{
InitializeComponent();
}
private void ProjectsWindow_Loaded(object sender, RoutedEventArgs e)
{
ProjectViewModel projectViewModel = new ProjectViewModel();
DataContext = projectViewModel;
}
}
}
ProjectViewModel.cs
using System;
using System.Collections.Generic;
using System.Windows.Input;
namespace MVVM
{
public class ProjectViewModel
{
RelayCommand saveCommand;
private IList<Project> projectList;
public ProjectViewModel()
{
projectList = new List<Project>
{
new Project{ProjectCode="P1", ProjectDescription="Project1"},
new Project{ProjectCode="P2", ProjectDescription="Project2"}
};
}
public IList<Project> Projects
{
get { return projectList; }
set { projectList = value; }
}
public ICommand SaveCommand
{
get
{
if (saveCommand == null)
{
saveCommand = new RelayCommand(
param => this.Save(),
param => this.CanSave
);
}
return saveCommand;
}
}
public void Save()
{
//
implement your Save function
}
bool CanSave
{
get { return true; }
}
}
}
RelayCommand.cs
using System;
using System.Diagnostics;
using System.Windows.Input;
namespace MVVM
{
/// <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
Fields
readonly Action<object> _execute;
readonly Predicate<object> _canExecute;
#endregion // Fields
#region
Constructors
/// <summary>
/// Creates a new command that can always execute.
/// </summary>
/// <param
name="execute">The execution logic.</param>
public RelayCommand(Action<object> execute)
: this(execute, null)
{
}
/// <summary>
/// Creates a new command.
/// </summary>
/// <param
name="execute">The execution logic.</param>
/// <param name="canExecute">The execution status logic.</param>
public RelayCommand(Action<object> execute, Predicate<object> canExecute)
{
if (execute == null)
throw new ArgumentNullException("execute");
_execute = execute;
_canExecute = canExecute;
}
#endregion // Constructors
#region
ICommand Members
[DebuggerStepThrough]
public bool CanExecute(object parameter)
{
return _canExecute == null ? true : _canExecute(parameter);
}
public event EventHandler CanExecuteChanged
{
add { CommandManager.RequerySuggested += value; }
remove { CommandManager.RequerySuggested -= value; }
}
public void Execute(object parameter)
{
_execute(parameter);
}
#endregion // ICommand Members
}
}
App.xaml
<Application x:Class="MVVM.App"
xmlns="http://schemas.microsoft.com/winfx/2006/xaml/presentation"
xmlns:x="http://schemas.microsoft.com/winfx/2006/xaml"
StartupUri="View/Projects.xaml">
<Application.Resources>
</Application.Resources>
</Application>
Run the application
