How to sort an array

You need to test before you actually call this function.  You would have code that is populating the array and it is there that you should test if the array has at least one item in it.  Here is some example code, I used the Samples project and the Sample-Employees.IMD file as it doesn't have any date fields.  Before calling the sort I check to see if there is anything in the array using a boolean that I created to track if the array has any items.

Dim listbox1$()

Sub Main
	Call populateArray()
End Sub

Function populateArray()
	Dim i As Integer
	Dim bFirstPass As Boolean
	
	bFirstPass = True
	Set db = Client.OpenDatabase("Sample-Employees.IMD")
		Set table = db.TableDef
			For i = 1 To table.count
				Set field = table.GetFieldAt(i)
					If field.IsDate Then
						If bFirstPass Then
							bFirstPass = False
							ReDim listbox1$(0)
							listbox1$(0) = field.name
						Else
							ReDim preserve listbox1$(UBound(listbox1$) + 1)
							listbox1$(UBound(listbox1$)) = field.name
						End If
					End If
			Next i
		Set table = Nothing
		db.close
	Set db = Nothing
	If bFirstPass Then
		MsgBox "There are no date fields in this file"
	Else
		Call sortArray(listbox1$)
	End If
End Function

Private Function sortArray(MyArray() As String)
	Dim lLoop, lLoop2 As Integer
	Dim str1, str2 As String
	For lLoop = 0 To UBound(MyArray)
	
		For lLoop2 = lLoop To UBound(MyArray)
		
			If UCase(MyArray(lLoop2)) < UCase(MyArray(lLoop)) Then
			
				str1 = MyArray(lLoop)
				str2 = MyArray(lLoop2)
				MyArray(lLoop) = str2
				MyArray(lLoop2) = str1
			
			End If
		
		Next lLoop2
	
	Next lLoop

End Function