Example of code to Validate field in axapta using validate method of datasource

Example of code to Validate field in axapta using validate method of datasource

 public boolean validateField(fieldId _fieldIdToCheck)  
 {  
 boolean ret;  
 ret = super(_fieldIdToCheck);  
 if (ret)  
 {  
 switch (_fieldIdToCheck)  
 {  
 case fieldnum(MyTable, custName) :  
 if (strlen(this.custName) <= 3)  
 ret = checkFailed("Customer name must be longer than 3 characters.");  
 }  
 }  
 return ret;  
 }