i want check value if Item="38",column="4" is NULL give system show message

if I want check value by when I click at item "29" already if value at Form="179",Item="38",column="4" is empty give system show message warning "input value" i will code?

Code VB.NET

If (pVal.FormTypeEx = 179) Then

Dim EventEnum As SAPbouiCOM.BoEventTypes

EventEnum = pVal.EventType

If pVal.ItemUID = "29" Then

If pVal.EventType = SAPbouiCOM.BoEventTypes.et_CLICK Then

...

if Item="38" column ="4" is null give system show message warning

...