To make a BC read only on clicking Submit

Create 2 BC User Properties as shown below:
1) Name: Named Method
Value:"Submit", "SET", "Status", "LookupValue(""EVENT_STATUS"", ""Submitted"")"
2) Name:BC Read Only Field
Value: BC Read Only Flag

Create a Calculated field: BC Read Only Flag
Calculated - True
Calculated Value - IIF([Status] = LookupValue ("EVENT_STATUS", "Submitted"),'Y','N')