Stored Procedure Dbo.SalesByCategory Of Northwind Database: Enter The Query String - Query Attempt Failed. How To Do It Right?

Hi all,
In the Programmability/Stored Procedure of Northwind Database in my SQL Server Management Studio Express (SSMSE), I have the following sql:


USE [Northwind]

GO

/****** Object: StoredProcedure [dbo].[SalesByCategory] Script Date: 03/25/2008 08:31:09 ******/

SET ANSI_NULLS ON

GO

SET QUOTED_IDENTIFIER ON

GO

CREATE PROCEDURE [dbo].[SalesByCategory]

@CategoryName nvarchar(15), @OrdYear nvarchar(4) = '1998'

AS

IF @OrdYear != '1996' AND @OrdYear != '1997' AND @OrdYear != '1998'

BEGIN

SELECT @OrdYear = '1998'

END

SELECT ProductName,

TotalPurchase=ROUND(SUM(CONVERT(decimal(14,2), OD.Quantity * (1-OD.Discount) * OD.UnitPrice)), 0)

FROM [Order Details] OD, Orders O, Products P, Categories C

WHERE OD.OrderID = O.OrderID

AND OD.ProductID = P.ProductID

AND P.CategoryID = C.CategoryID

AND C.CategoryName = @CategoryName

AND SUBSTRING(CONVERT(nvarchar(22), O.OrderDate, 111), 1, 4) = @OrdYear

GROUP BY ProductName

ORDER BY ProductName

////////////////////////////////////////////////////////////////////////////////////////////////////////////////////////////////////////
From an ADO.NET 2.0 book, I copied the code of ConnectionPoolingForm to my VB 2005 Express. The following is part of the code:

Imports System.Collections.Generic

Imports System.ComponentModel

Imports System.Drawing

Imports System.Text

Imports System.Windows.Forms

Imports System.Data

Imports System.Data.SqlClient

Imports System.Data.Common

Imports System.Diagnostics

Public Class ConnectionPoolingForm

Dim _ProviderFactory As DbProviderFactory = SqlClientFactory.Instance

Public Sub New()

' This call is required by the Windows Form Designer.

InitializeComponent()

' Add any initialization after the InitializeComponent() call.

'Force app to be available for SqlClient perf counting

Using cn As New SqlConnection()

End Using

InitializeMinSize()

InitializePerfCounters()

End Sub

Sub InitializeMinSize()

Me.MinimumSize = Me.Size

End Sub

Dim _SelectedConnection As DbConnection = Nothing

Sub lstConnections_SelectedIndexChanged(ByVal sender As Object, ByVal e As EventArgs) Handles lstConnections.SelectedIndexChanged

_SelectedConnection = DirectCast(lstConnections.SelectedItem, DbConnection)

EnableOrDisableButtons(_SelectedConnection)

End Sub

Sub DisableAllButtons()

btnAdd.Enabled = False

btnOpen.Enabled = False

btnQuery.Enabled = False

btnClose.Enabled = False

btnRemove.Enabled = False

btnClearPool.Enabled = False

btnClearAllPools.Enabled = False

End Sub

Sub EnableOrDisableButtons(ByVal cn As DbConnection)

btnAdd.Enabled = True

If cn Is Nothing Then

btnOpen.Enabled = False

btnQuery.Enabled = False

btnClose.Enabled = False

btnRemove.Enabled = False

btnClearPool.Enabled = False

Else

Dim connectionState As ConnectionState = cn.State

btnOpen.Enabled = (connectionState = connectionState.Closed)

btnQuery.Enabled = (connectionState = connectionState.Open)

btnClose.Enabled = btnQuery.Enabled

btnRemove.Enabled = True

If Not (TryCast(cn, SqlConnection) Is Nothing) Then

btnClearPool.Enabled = True

End If

End If

btnClearAllPools.Enabled = True

End Sub

Sub StartWaitUI()

Me.Cursor = Cursors.WaitCursor

DisableAllButtons()

End Sub

Sub EndWaitUI()

Me.Cursor = Cursors.Default

EnableOrDisableButtons(_SelectedConnection)

End Sub

Sub SetStatus(ByVal NewStatus As String)

RefreshPerfCounters()

Me.statusStrip.Items(0).Text = NewStatus

End Sub

Sub btnConnectionString_Click(ByVal sender As Object, ByVal e As EventArgs) Handles btnConnectionString.Click

Dim strConn As String = txtConnectionString.Text

Dim bldr As DbConnectionStringBuilder = _ProviderFactory.CreateConnectionStringBuilder()

Try

bldr.ConnectionString = strConn

Catch ex As Exception

MessageBox.Show(ex.Message, "Invalid connection string for " + bldr.GetType().Name, MessageBoxButtons.OK, MessageBoxIcon.Error)

Return

End Try

Dim dlg As New ConnectionStringBuilderDialog()

If dlg.EditConnectionString(_ProviderFactory, bldr) = System.Windows.Forms.DialogResult.OK Then

txtConnectionString.Text = dlg.ConnectionString

SetStatus("Ready")

Else

SetStatus("Operation cancelled")

End If

End Sub

Sub btnAdd_Click(ByVal sender As Object, ByVal e As EventArgs) Handles btnAdd.Click

Dim blnError As Boolean = False

Dim strErrorMessage As String = ""

Dim strErrorCaption As String = "Connection attempt failed"

StartWaitUI()

Try

Dim cn As DbConnection = _ProviderFactory.CreateConnection()

cn.ConnectionString = txtConnectionString.Text

cn.Open()

lstConnections.SelectedIndex = lstConnections.Items.Add(cn)

Catch ex As Exception

blnError = True

strErrorMessage = ex.Message

End Try

EndWaitUI()

If blnError Then

SetStatus(strErrorCaption)

MessageBox.Show(strErrorMessage, strErrorCaption, MessageBoxButtons.OK, MessageBoxIcon.Error)

Else

SetStatus("Connection opened succesfully")

End If

End Sub

Sub btnOpen_Click(ByVal sender As Object, ByVal e As EventArgs) Handles btnOpen.Click

StartWaitUI()

Try

_SelectedConnection.Open()

EnableOrDisableButtons(_SelectedConnection)

SetStatus("Connection opened succesfully")

EndWaitUI()

Catch ex As Exception

EndWaitUI()

Dim strErrorCaption As String = "Connection attempt failed"

SetStatus(strErrorCaption)

MessageBox.Show(ex.Message, strErrorCaption, MessageBoxButtons.OK, MessageBoxIcon.Error)

End Try

End Sub

Sub btnQuery_Click(ByVal sender As Object, ByVal e As EventArgs) Handles btnQuery.Click

Dim queryDialog As New QueryDialog()

If queryDialog.ShowDialog() = System.Windows.Forms.DialogResult.OK Then

Me.Cursor = Cursors.WaitCursor

DisableAllButtons()

Try

Dim cmd As DbCommand = _SelectedConnection.CreateCommand()

cmd.CommandText = queryDialog.txtQuery.Text

Using rdr As DbDataReader = cmd.ExecuteReader()

If rdr.HasRows Then

Dim resultsForm As New QueryResultsForm()

resultsForm.ShowResults(cmd.CommandText, rdr)

SetStatus(String.Format("Query returned {0} row(s)", resultsForm.RowsReturned))

Else

SetStatus(String.Format("Query affected {0} row(s)", rdr.RecordsAffected))

End If

Me.Cursor = Cursors.Default

EnableOrDisableButtons(_SelectedConnection)

End Using

Catch ex As Exception

Me.Cursor = Cursors.Default

EnableOrDisableButtons(_SelectedConnection)

Dim strErrorCaption As String = "Query attempt failed"

SetStatus(strErrorCaption)

MessageBox.Show(ex.Message, strErrorCaption, MessageBoxButtons.OK, MessageBoxIcon.Error)

End Try

Else

SetStatus("Operation cancelled")

End If

End Sub
///////////////////////////////////////////////////////////////////////////////////////////////////////////////////////
I executed the code successfully and I got a box which asked for "Enter the query string".
I typed in the following: EXEC dbo.SalesByCategory @Seafood. I got the following box: Query attempt failed. Must declare the scalar variable "@Seafood". I am learning how to enter the string for the "SQL query programed in the subQuery_Click(ByVal sender As Object, ByVal e As EventArgs) Handles btnQuery.Click" (see the code statements listed above). Please help and tell me what I missed and what I should put into the query string to get the information of the "Seafood" category out.

Thanks in advance,
Scott Chang