根据我上面的评论,您可以利用RelayCommand
它来执行这种操作,因为它具有CanExecute
自行评估的功能,因此不需要NotifyPropertyChanged
事件来启用/禁用Button
这是一个完整的例子,展示了这个工作,因为它可能有点难以解释
xml:
<Window x:Class="WpfApplication8.MainWindow"
xmlns="http://schemas.microsoft.com/winfx/2006/xaml/presentation"
xmlns:x="http://schemas.microsoft.com/winfx/2006/xaml"
Title="MainWindow" Height="315" Width="258" Name="UI">
<Grid DataContext="{Binding ElementName=UI}">
<DataGrid Name="dataGrid" CanUserAddRows="False" CanUserReorderColumns="False" HeadersVisibility="Column" AutoGenerateColumns="False" ItemsSource="{Binding Activities}" SelectedItem="{Binding SelectedActivity, Mode=TwoWay}" Margin="10,10,10,37" >
<DataGrid.Columns>
<DataGridTextColumn Header="Column1" Binding="{Binding Column1}" />
<DataGridTemplateColumn Header="Enabled">
<DataGridTemplateColumn.CellTemplate>
<DataTemplate>
<CheckBox HorizontalAlignment="Center" VerticalAlignment="Center" IsChecked="{Binding Enabled, UpdateSourceTrigger=PropertyChanged}"/>
</DataTemplate>
</DataGridTemplateColumn.CellTemplate>
</DataGridTemplateColumn>
</DataGrid.Columns>
</DataGrid>
<Button Command="{Binding MyButtonCommand}" Content="Is any checked & is any 'Item6' " Margin="10,0,9,10" Height="22" VerticalAlignment="Bottom"/>
</Grid>
</Window>
代码:
namespace WpfApplication8
{
/// <summary>
/// Interaction logic for MainWindow.xaml
/// </summary>
public partial class MainWindow : Window
{
private ObservableCollection<TestObject> myVar = new ObservableCollection<TestObject>();
public MainWindow()
{
MyButtonCommand = new RelayCommand(ExecuteButtonAction, CanButtonExecute);
InitializeComponent();
for (int i = 0; i < 100; i++)
{
Activities.Add(new TestObject { Column1 = "Item" + i, Enabled = false });
}
}
public ICommand MyButtonCommand { get; set; }
public ObservableCollection<TestObject> Activities
{
get { return myVar; }
set { myVar = value; }
}
private bool CanButtonExecute()
{
return Activities.Any(x => x.Enabled) && Activities.Any(x => x.Column1 == "Item2");
}
private void ExecuteButtonAction()
{
// button clicked
}
}
public class TestObject : INotifyPropertyChanged
{
private string _column1;
private bool _enabled;
public string Column1
{
get { return _column1; }
set { _column1 = value; NotifyPropertyChanged(); }
}
public bool Enabled
{
get { return _enabled; }
set { _enabled = value; NotifyPropertyChanged(); }
}
public event PropertyChangedEventHandler PropertyChanged;
public void NotifyPropertyChanged([CallerMemberName]string propertyName = null)
{
if (PropertyChanged != null)
{
PropertyChanged(this, new PropertyChangedEventArgs(propertyName));
}
}
}
public class RelayCommand : ICommand
{
private readonly Action _execute;
private readonly Func<bool> _canExecute;
/// <summary>
/// Creates a new command that can always execute.
/// </summary>
/// <param name="execute">The execution logic.</param>
public RelayCommand(Action 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 execute, Func<bool> canExecute)
{
if (execute == null)
throw new ArgumentNullException("execute");
_execute = execute;
_canExecute = canExecute;
}
[DebuggerStepThrough]
public bool CanExecute(object parameter)
{
return _canExecute == null ? true : _canExecute();
}
public event EventHandler CanExecuteChanged
{
add
{
if (_canExecute != null)
{
CommandManager.RequerySuggested += value;
}
}
remove
{
if (_canExecute != null)
{
CommandManager.RequerySuggested -= value;
}
}
}
public void Execute(object parameter)
{
_execute();
}
}
}
结果:(是否检查了任何项目并且是任何项目“Item6”)