• XMLports
  

The FileName property must be set to a valid file name or a run-time error occurs.

This property can be set dynamically by using the FILENAME Function (XMLport). Using this function together with the Import function, you can create XMLports that are dynamic. This means that they can determine whether data is input or output at run time, and the name of the external file to read from or write to can also be set at run time.

If FileName is blank, then a default request options page tab will be created, where this property can be set at run time. If no name is specified or the UseRequestPage Property is set to No, then a run-time error occurs.

Reference