Add interface ICommandSource

src/Avalonia.Input/ICommandSource.cs

@@ -0,0 +1,31 @@
+using System.Windows.Input;
+
+namespace Avalonia.Input
+{
+    ///<summary>
+    /// An interface for classes that know how to invoke a Command.
+    ///</summary>
+    public interface ICommandSource
+    {
+        /// <summary>
+        /// The command that will be executed when the class is "invoked."
+        /// Classes that implement this interface should enable or disable based on the command's CanExecute return value.
+        /// The property may be implemented as read-write if desired.
+        /// </summary>
+        ICommand Command { get; }
+
+        /// <summary>
+        /// The parameter that will be passed to the command when executing the command.
+        /// The property may be implemented as read-write if desired.
+        /// </summary>
+        object CommandParameter { get; }
+
+
+        /// <summary>
+        /// Bor the bheavior CanExecuteChanged
+        /// </summary>
+        /// <param name="sender"></param>
+        /// <param name="e"></param>
+        void CanExecuteChanged(object sender, System.EventArgs e);
+    }
+}