Command not executing when clicking a button - wpf

Question

How should the collection be bound to Listview and have the button execute the command to add a single user to the collection.
View Model Code:
public class ViewModelBase : INotifyPropertyChanged
{
public event PropertyChangedEventHandler PropertyChanged;
public void OnPropertyChanged(string name)
{
if (PropertyChanged != null)
PropertyChanged(this, new PropertyChangedEventArgs(name));
}
}
public class UserViewModel : ViewModelBase
{
private ObservableCollection<User> _UsersList;
private User _user;
public UserViewModel()
{
_user = new User();
_UsersList = new ObservableCollection<User>();
_UsersList.CollectionChanged += _UsersList_CollectionChanged;
}
private void _UsersList_CollectionChanged(object sender, System.Collections.Specialized.NotifyCollectionChangedEventArgs e)
{
}
public ObservableCollection<User> Users
{
get { return _UsersList; }
set
{
_UsersList = value;
OnPropertyChanged("Users");
}
}
public User User
{
get
{
return _user;
}
set
{
_user = value;
OnPropertyChanged("User");
}
}
private ICommand mUpdater;
public ICommand UpdateCommand
{
get
{
if (mUpdater == null)
mUpdater = new Updater(this);
return mUpdater;
}
//set
//{
// mUpdater = value;
//}
}
private void Submit()
{
Users.Add(User);
User = new User();
}
private class Updater : ICommand
{
#region ICommand Members
UserViewModel _obj;
public Updater(UserViewModel obj)
{
_obj = obj;
}
public bool CanExecute(object parameter)
{
return true;
}
public event EventHandler CanExecuteChanged
{
add { CommandManager.RequerySuggested += value; }
remove { CommandManager.RequerySuggested -= value; }
}
public void Execute(object parameter)
{
_obj.Submit();
}
}
View Xaml:
<ListView Name="UserGrid"
Grid.Row="1"
Margin="4,178,12,13"
ItemsSource="{Binding Users}" >
<ListView.View>
<GridView x:Name="grdTest">
<GridViewColumn Header="UserId"
DisplayMemberBinding="{Binding UserId}"
Width="50"/>
</GridView>
</ListView.View>
</ListView>
<TextBlock Grid.Row="0"
Grid.Column="0"
Text="Name"
HorizontalAlignment="Center"/>
<TextBox Grid.Row="0"
Grid.Column="1"
Width="100"
HorizontalAlignment="Center"
Text="{Binding User.UserId, Mode=TwoWay}"/>
<Button Content="Update"
Grid.Row="1"
Height="23"
HorizontalAlignment="Left"
Margin="310,40,0,0"
Name="btnUpdate"
VerticalAlignment="Top"
Width="141"
Command="{Binding Path=UpdateCommad}" />

Answer 1

The error is in the binding of the button to the command:
Command="{Binding Path=UpdateCommad}" />
It should be:
Command="{Binding Path=UpdateCommand}" />
To find errors like this always read the Debug Output. In this case it quickly showed:
System.Windows.Data Error: 40 : BindingExpression path error:
'UpdateCommad' property not found on 'object' ''UserViewModel'
To prevent this from happening at all you could use Xaml code completion by setting the design-time DataContext type:
<Window x:Class="TestWpfApplication.MainWindow"
xmlns="http://schemas.microsoft.com/winfx/2006/xaml/presentation"
xmlns:x="http://schemas.microsoft.com/winfx/2006/xaml"
xmlns:d="http://schemas.microsoft.com/expression/blend/2008"
xmlns:mc="http://schemas.openxmlformats.org/markup-compatibility/2006"
xmlns:local="clr-namespace:TestWpfApplication"
mc:Ignorable="d"
Title="MainWindow"
Height="350"
Width="525"
d:DataContext="{d:DesignInstance Type=local:UserViewModel}">
After setting this you will have code-completion in Xaml: just start typing the binding path and it will offer valid options.