From jscript (or vbscript) how to dynamically invoke a method from a COM object?

Question

JScript allows funky features like .apply(), whereby you can invoke a method by name, passing an array of arguments to invoke the method with. However this applies to JScript (javascript) objects, and obviously won't work on a COM component - but this is the feature I am looking for.

Is there a way to invoke a COM object method, by name, and with dynamic args from JScript? I couldn't find anything.

Thanks!

Tony Lee · Accepted Answer · 2011-07-06 15:30:50Z

1

Dynamically build the script you want to call as a string then invoke it using eval(). eg eval("someObj.method()") or eval(objName + "." + methodName + "(" + args.join(",") +")").

edited Jul 6, 2011 at 15:30

answered Jun 30, 2011 at 0:54

Tony Lee

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3 Comments

Troy Parsons Over a year ago

Thanks for the response. Main issue with eval() is that I can't pass in a dynamic number of arguments. methodOne() may take one argument while methodTwo() takes two arguments.

Tony Lee Over a year ago

@Troy - eval takes a string so you can build it dynamically. I added an example.

Troy Parsons Over a year ago

Sorry... my response was not clear :( although you can build the string, there is no reflection available to know how many args to pass.

Troy Parsons · Accepted Answer · 2011-07-01 05:26:19Z

0

Since I'm using WSC (Windows Script Component) I have made a workaround whereby I generate a wrapper script using XSL, transforming the input WSC (which is an XML file). The XSL generates a switch{} statement with a case for each method, supplying the correct number of args for each method.

Not quite what I was after, but I get better error checking :)

answered Jul 1, 2011 at 5:26

Troy Parsons

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