Code

// Checks all subform records to see if any subrecord exists with
// the specified value in the specified field.
// Arguments:
// aCheckVal - Value to look for
// aForm - Name of subform
// aField - Name of field to check
// Returns True if a matching record is found

FUNCTION ExistsInSubform(aCheckVal as String, aForm as String, aField as String) as Boolean
var vRet as Boolean
var vLoop as Int
var vCount as Int
var vVal as String

	vRet = False
	vCount = @FormResultSetTotal(aForm)
	vLoop = 1
	While (vLoop <= vCount) And (vRet = False)
	{
		vVal = @FormFieldValue(aForm, aField, vLoop)
		If vVal = aCheckVal
		{
			vRet = True
		}
		vLoop = vLoop + 1
	}
	Return vRet

END FUNCTION

// Example of use to check if the value entered in the NewItemCode element appears in
// any record in the Articles subform in the element called ItemCode.

	If ExistsInSubform(NewItemCode, "Articles", "ItemCode")
	{
		@MsgBox("Error: Record alread exists.")
	}
	Else
	{
		// Do add record
	}