icommand

I'm developing a WPF application with the MVVM pattern, RelayCommand, etc. I read a lot on this question but I am not clear as to: All I want to do is move a shape, like an ellipse, for example, and capture its final position, to put in the database. But I can't bind events (MouseLetButtonDown, MouseLeftButtonUp and MouseMove) to commands. I've read about attached behaviours , but I need the arguments of the events (MouseButtonEventArgs and MouseEventArgs) to retrieve the position. Solution? Rick Sladkey When writing an MVVM graphical application, it is tempting to try to send all the events

There is a lot of effort in the Silverlight community to keep a XAML's code behind file as free of code as possible. What is the real motivation behind this? For example, what is the advantage of using a command instead of an event handler? If I have <Button x:Name="SaveButton" Content="Save" Click="SaveButton_Click" /> ... private void SaveButton_Click(object sender, RoutedEventArgs e) { _myViewModel.SaveChanges(); } Then why is this prefered? <Button x:Name="SaveButton" Content="Save" Command="{Binding SaveCommand}" /> Where obviously the SaveCommand in my view model is effectively going to

I try to do something like this: <DataGrid Name="myGrid" ItemSource="{Binding Path=MyCollection}"> <DataGrid.ContextMenu> <ContextMenu> <MenuItem Command="{Binding RemoveRow}" CommandParameter="{Binding ElementName=myGrid, Path=SelectedItem}"> </ContextMenu> </DataGridContextMenu> </DataGrid> but I got null always (I tried also SelectedIndex and SelectedValue) if I pass the following parameter to the execution code, it works: <MenuItem Command="{Binding RemoveRow}" CommandParameter="1"> Try something like this in your CommandParameter, <DataGrid.ContextMenu> <ContextMenu> <MenuItem Header=

Sometimes we used complex ways so many times, we forgot the simplest ways to do the task. I know how to do command binding, but i always use same approach. Create a class that implements ICommand interface and from the view model i create new instance of that class and binding works like a charm. This is the code that i used for command binding public partial class MainWindow : Window { public MainWindow() { InitializeComponent(); DataContext = this; testCommand = new MeCommand(processor); } ICommand testCommand; public ICommand test { get { return testCommand; } } public void processor() {

Let's have a button Command property bound to a custom command. When should I implement ICommand and when derive from RoutedCommand ? I see that RoutedCommand implements ICommand . In which case could I need to iplement an ICommand ? What about MVVM model? Which one suits better for this purpose? Richard McGuire As you have noticed the RoutedCommand class is an implementation of the ICommand interface, its main distinction if that its function is similar to that of a RoutedEvent : The Execute and CanExecute methods on a RoutedCommand do not contain the application logic for the command as is

I'm having some difficulty with Context Menu commands on my View Model. I'm implementing the ICommand interface for each command within the View Model, then creating a ContextMenu within the resources of the View (MainWindow), and using a CommandReference from the MVVMToolkit to access the current DataContext (ViewModel) Commands. When I debug the application, it appears that the CanExecute method on the command is not being called except at the creation of the window, therefore my Context MenuItems are not being enabled or disabled as I would have expected. I've cooked up a simple sample (