>>It might work. You need to use semicolon between commands in T-SQL and I also suggest to use Add instead of AddWithValue, but the idea is this. Also, I think this should be part of the whole UPDATE command, e.g. it should be the same batch.
>
>Revise it like this?
>

>oConn.Open()
>oCommand.Text = "UPDATE myTable SET ...; DECLARE @ContextInfo varbinary(128);SELECT @ContextInfo = cast( @User AS varbinary(128) );SET CONTEXT_INFO @ContextInfo"
>oCommand.Parameters.Add("@User", SqlDbType.Char).Value = GetUser.Name 
>oCommand.ExecuteNonQuery()
>oConn.Close()
>

The UPDATE command should be last in that script.