namespace Microsoft.Practices.Prism.Commands
{
    // Summary:
    //     An System.Windows.Input.ICommand whose delegates can be attached for Microsoft.Practices.Prism.Commands.DelegateCommand<T>.Execute(T)
    //     and Microsoft.Practices.Prism.Commands.DelegateCommand<T>.CanExecute(T).
    //      It also implements the Microsoft.Practices.Prism.IActiveAware interface,
    //     which is useful when registering this command in a Microsoft.Practices.Prism.Commands.CompositeCommand
    //     that monitors command's activity.
    //
    // Type parameters:
    //   T:
    //     Parameter type.
    //
    // Remarks:
    //     The constructor deliberately prevent the use of value types.  Because ICommand
    //     takes an object, having a value type for T would cause unexpected behavior
    //     when CanExecute(null) is called during XAML initialization for command bindings.
    //      Using default(T) was considered and rejected as a solution because the implementor
    //     would not be able to distinguish between a valid and defaulted values.
    //     Instead, callers should support a value type by using a nullable value type
    //     and checking the HasValue property before using the Value property.  public
    //     MyClass() { this.submitCommand = new DelegateCommand<int?>(this.Submit, this.CanSubmit);
    //     } private bool CanSubmit(int? customerId) { return (customerId.HasValue &&
    //     customers.Contains(customerId.Value)); }
    public class DelegateCommand<T> : DelegateCommandBase
    {
        // Summary:
        //     Initializes a new instance of Microsoft.Practices.Prism.Commands.DelegateCommand<T>.
        //
        // Parameters:
        //   executeMethod:
        //     Delegate to execute when Execute is called on the command. This can be null
        //     to just hook up a CanExecute delegate.
        //
        // Remarks:
        //     Microsoft.Practices.Prism.Commands.DelegateCommand<T>.CanExecute(T) will
        //     always return true.
        public DelegateCommand(Action<T> executeMethod);
        //
        // Summary:
        //     Initializes a new instance of Microsoft.Practices.Prism.Commands.DelegateCommand<T>.
        //
        // Parameters:
        //   executeMethod:
        //     Delegate to execute when Execute is called on the command. This can be null
        //     to just hook up a CanExecute delegate.
        //
        //   canExecuteMethod:
        //     Delegate to execute when CanExecute is called on the command. This can be
        //     null.
        //
        // Exceptions:
        //   System.ArgumentNullException:
        //     When both executeMethod and canExecuteMethod ar null.
        public DelegateCommand(Action<T> executeMethod, Func<T, bool> canExecuteMethod);

        // Summary:
        //     Determines if the command can execute by invoked the System.Func<T,TResult>
        //     provided during construction.
        //
        // Parameters:
        //   parameter:
        //     Data used by the command to determine if it can execute.
        //
        // Returns:
        //     true if this command can be executed; otherwise, false.
        public bool CanExecute(T parameter);
        //
        // Summary:
        //     Executes the command and invokes the System.Action<T> provided during construction.
        //
        // Parameters:
        //   parameter:
        //     Data used by the command.
        public void Execute(T parameter);
    }
}