ASP.Net中使用VB.Net调用存储过程并得到返回值

//存储过程代码
CREATE PROCEDURE [AddNewInvoiceInfo] (@sUserID int,@sClaimMethod varchar(50),@sInvoiceNum varchar(50),@sInvoiceDate datetime,@sBuyCity varchar(50))AS
Insert Into SMB_InvoiceInfo (MemberID,ClaimMethod,InvoiceNum,InvoiceDate,InvoiceCity) Values (@sUserID,@sClaimMethod,@sInvoiceNum,@sInvoiceDate,@sBuyCity)
return @@IDENTITY
GO

//调用存储过程代码
Dim CN As New SqlConnection()
Dim InvoiceID As String
Try
CN.ConnectionString = DBConStr
CN.Open()
Dim CMD As SqlCommand
CMD = New SqlCommand("AddNewInvoiceInfo", CN)
CMD.CommandType = CommandType.StoredProcedure

CMD.Parameters.Add(New SqlParameter("@sUserID", SqlDbType.Int))
CMD.Parameters("@sUserID").Value = CInt(UserID.Text)

CMD.Parameters.Add(New SqlParameter("@sClaimMethod", SqlDbType.VarChar, 50))
CMD.Parameters("@sClaimMethod").Value = TransName.Text

CMD.Parameters.Add(New SqlParameter("@sInvoiceNum", SqlDbType.VarChar, 50))
CMD.Parameters("@sInvoiceNum").Value = InvoiceNum.Text

CMD.Parameters.Add(New SqlParameter("@sInvoiceDate", SqlDbType.DateTime))
CMD.Parameters("@sInvoiceDate").Value = InvoiceDate.SelectedDate.Date

CMD.Parameters.Add(New SqlParameter("@sBuyCity", SqlDbType.VarChar, 50))
CMD.Parameters("@sBuyCity").Value = BuyCity.Text

CMD.Parameters.Add(New SqlParameter("@sInvoiceID", SqlDbType.Int))
CMD.Parameters("@sInvoiceID").Direction = ParameterDirection.ReturnValue

CMD.ExecuteNonQuery()
InvoiceID = CMD.Parameters("@sInvoiceID").Value.ToString()
CMD.Dispose()
Catch ex As Exception
Response.Write(ex.ToString())
Finally
CN.Close()
End Try