| <?xml version="1.0" encoding="UTF-8"?> | 
| <ValidationRule xmlns="http://soap.sforce.com/2006/04/metadata"> | 
|     <fullName>Cannot_Change_Date</fullName> | 
|     <active>true</active> | 
|     <description>维护日期不可修改</description> | 
|     <errorConditionFormula>!ISNEW() && ISCHANGED(Date__c)</errorConditionFormula> | 
|     <errorMessage>维护日期不可修改</errorMessage> | 
| </ValidationRule> |