我正在使用正则表达式Switch([Steps]![OF]>0 And [Steps]![CC]="Ocean Freight","3PL",
[Steps]![AF]>0 And [Steps]![CC]="Air_Freight","Air Freight",
[Steps]![Dray]>0 And [Steps]![CC]="Drayage Management","3PL",
[Steps]![PO 4PL]>0 And [Steps]![CC]="PO_Management","4PL",
[Steps]![PO 3PL]>0 And [Steps]![CC]="PO_Management","3PL",
[Steps]![CROM 4PL]>0 And [Steps]![CC]="CROM Fee","4PL",
[Steps]![CROM 3PL]>0 And [Steps]![CC]="CROM Fee","3PL",
[Steps]![EDI 4PL]>0 And [Steps]![CC]="EDI","4PL",
True, Switch(
[Steps]![EDI 3PL]>0 And [Steps]![CC]="EDI","3PL",
[Steps]![BMF 4PL]>0 And [Steps]![CC]="Booking Management Fee","4PL",
[Steps]![BMF 3PL]>0 And [Steps]![CC]="Booking Management Fee","3PL",
[Steps]![FF 4PL]>0 And [Steps]![CC]="Forwarding Fee","4PL",
[Steps]![FF 3PL]>0 And [Steps]![CC]="Forwarding Fee","3PL",
[Steps]![Handling 4PL] >0 and [Steps]![CC]="Handling Charge","4PL",
[Steps]![Handling 3PL] >0 and [Steps]![CC]="Handling Charge","3PL"))
来限制用户在开头输入空格。我在这里做错了什么，当我输入一个字符时，会出现验证消息，要求输入该字段（根据逻辑和角度材料）。