internal static void RegisterAdapter(CommandAdapterBase <TInvoker> adapter, IUIElement key)
{
List <CommandAdapterBase <TInvoker> > invokers;
// if this is the first time we've seen this key, create a list for the adapters
if (adapters.TryGetValue(key, out invokers) == false)
{
invokers = new List <CommandAdapterBase <TInvoker> >();
adapters.Add(key, invokers);
}
// store a reference to the adapter in the list
invokers.Add(adapter);
// also store the key using the adapter as the key
adapterKey.Add(adapter, key);
Command command = adapter.Command;
if (null != command)
{
// add command and verify element state
AddCommand(command, key);
}
// verify/update the state of the key
VerifyCommandState(key);
}
private static void VerifyCommandState(IUIElement logicalElement)
{
List <Command> commands;
CommandStatus status = CommandStatus.Unavailable;
Command commandWithStatus = null;
// if we have commands associated with the element...
if (elementCommands.TryGetValue(logicalElement, out commands))
{
for (int i = 0, len = commands.Count; i < len; i++)
{
Command cmd = commands[i];
if (cmd.Status == CommandStatus.Disabled)
{
status = CommandStatus.Disabled;
commandWithStatus = cmd;
}
else if (cmd.Status == CommandStatus.Enabled)
{
status = CommandStatus.Enabled;
break;
}
}
}
logicalElement.UpdateState(status);
// invoke a method on the command adapters so
// derived command adapters can react to the change
List <CommandAdapterBase <TInvoker> > cmdAdapters;
if (adapters.TryGetValue(logicalElement, out cmdAdapters))
{
for (int i = 0, len = cmdAdapters.Count; i < len; i++)
{
CommandAdapterBase <TInvoker> cmdAdapter = cmdAdapters[i];
cmdAdapter.OnInvokerStateChanged();
}
}
}
internal static void NotifyCommandChanged(CommandAdapterBase <TInvoker> adapter, Command oldCommand, Command newCommand)
{
IUIElement logicalElement;
// we only need to worry about it if, the adapter has been associated with an invoker/element
if (adapterKey.TryGetValue(adapter, out logicalElement))
{
if (null != oldCommand)
{
RemoveCommand(oldCommand, logicalElement);
}
if (null != newCommand)
{
AddCommand(newCommand, logicalElement);
}
VerifyCommandState(logicalElement);
}
}
internal static void UnregisterAdapter(CommandAdapterBase <TInvoker> adapter, IUIElement key)
{
List <CommandAdapterBase <TInvoker> > invokers;
if (adapters.TryGetValue(key, out invokers) == false)
{
throw new InvalidOperationException(Properties.Resources.UnrecognizedAdapterKey);
}
Debug.Assert(invokers.Contains(adapter), "The specified adapter is not associated with the specified key.");
// if this is the last invoker...
if (invokers.Count == 1)
{
if (invokers[0] != adapter)
{
throw new InvalidOperationException(Properties.Resources.InvalidAdapterForKey);
}
// remove the key as well
adapters.Remove(key);
}
else
{
invokers.Remove(adapter);
}
// remove the dictionary which relates the adapter to the key
adapterKey.Remove(adapter);
Command command = adapter.Command;
if (null != command)
{
// add command and verify element state
RemoveCommand(command, key);
// verify/update the state of the key
VerifyCommandState(key);
}
}