JobHead_AfterFieldChange - The type or namespace name 'DataColumnChangeEventArgs' could not be found

Attempting to customize Job Entry.

From the Customizations Tool Dialog > Wizards > Form Event Wizard > Select Event Type (AfterFieldChange) > Tables (JobHead) > Fields (Number01) > Update All Event Code

The code it generates is:

private void JobHead_AfterFieldChange(object sender, DataColumnChangeEventArgs args)
	// ** Argument Properties and Uses **
	// args.Row["FieldName"]
	// args.Column, args.ProposedValue, args.Row
	// Add Event Handler Code
	switch (args.Column.ColumnName)
		case "Number01":

Yet when I go to Tools > Test Code, I get:

Error: CS0246 - line 41 (958) - The type or namespace name 'DataColumnChangeEventArgs' could not be found (are you missing a using directive or an assembly reference?)

What now?! I don’t remember any special requirement in other modules?!

To use anything that references “DataColumnChangeEventArgs”, “using System.Data;” must be added at the top of the script, before “public class Script”.