How to pass c# list to nintex collection variable

Hi,

I need to pass a C# List to nintex collection variable programmatically to start a site workflow.This is the code i used to built associate data.

string.Format("<data><collectionVariable>" + ListName+ "</collectionVariable></data>"); 

Is it possible to use this list data as normal collection in nintex?

Please tell me whether i need to cast this list to map with nintex collection variable.

Thanks,

Vino