hiii,
To retrieve the value of a variable of a nullable type, you should first test its HasValue property to confirm that it has a value. If you try to read the value when HasValue is False, Visual Basic throws an InvalidOperationException exception. The following example shows the recommended way to read the variable Col2
If Col2.HasValue Then
Command.CommandText = "INSERT INTO SIGN(TYPESIGN_ID) VALUES('" + CStr(Col2) + "')"
End If