Reply To: Undo in XMAX 5.5

[XMetaLOldTimer]

Until we figure out a way to do some sort of beginUndo/endUndo, one option I can offer still requires invoking a XMAX macro…but that macro in turn just calls back into your code.  Your code can then do a series of mutation (i.e. external COM calls on XMAX).  Since those calls are still executed in the context of a macro, XMAX will log all the mutations as a group-command internally…that means the mutations will roll back with a single Undo call or Ctrl-Z.

Roughly, the implementation could go like this assuming MSIE is the XMAX container:

1. Implement the dispatcher macro that calls an object method of your
making.

        var xmaxContainerCmd = ActiveDocument.Host.QueryService(“YOURNEXTCMD”);
      xmaxContainerCmd.doIt();  // You define the method signature (i.e. interface)
      xmaxContainerCmd = null;
  ]]>

2. Implement IXMetaLControlEvents::OnQueryService(BSTR serviceName, DispRefVar* service)

    // MSIE Automagic event bind XMAX COM event sink to MSIE container,
    // assumes OBJECT id=”XMAX”
    function XMAX::OnQueryService(name, service)
    {
       switch (name) {
       case “YOURNEXTCMD”:
          var yourCmd = new Object;
          yourCmd.doIt = function() {
                                  // Notice the “doIt” signature here must match
                                  // what you wrote in the XMAX dispatcher.
                                  //
                                  // Write your XMAX calls here or delegate as needed
                                  };
          service.Value = yourCmd;
          break;
       }
    } 

The same pattern can be replayed in any XMAX container application provided you can provide an IDispatch callable object for the XMAX macro.

Regards,
Addam

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