Imports System
Imports System.Configuration
Imports System.Data
Imports System.Data.SqlClient
Imports System.Collections.Generic
Imports System.Web.UI
Imports System.Web.UI.WebControls
Namespace Samples.AspNet.ObjectDataSource
'
' Northwind Employee Data Factory
'
Public Class NorthwindData
Private _connectionString As String
Public Sub New()
Initialize()
End Sub
Public Sub Initialize()
' Initialize data source. Use "Northwind" connection string from configuration.
If ConfigurationManager.ConnectionStrings("Northwind") Is Nothing OrElse _
ConfigurationManager.ConnectionStrings("Northwind").ConnectionString.Trim() = "" Then
Throw New Exception("A connection string named 'Northwind' with a valid connection string " & _
"must exist in the <connectionStrings> configuration section for the application.")
End If
_connectionString = _
ConfigurationManager.ConnectionStrings("Northwind").ConnectionString
End Sub
' Select all employees.
Public Function GetAllEmployees(sortColumns As String, startRecord As Integer, maxRecords As Integer) As DataTable
VerifySortColumns(sortColumns)
Dim sqlCmd As String = "SELECT EmployeeID, LastName, FirstName, Address, City, Region, PostalCode FROM Employees "
If sortColumns.Trim() = "" Then
sqlCmd &= "ORDER BY EmployeeID"
Else
sqlCmd &= "ORDER BY " & sortColumns
End If
Dim conn As SqlConnection = New SqlConnection(_connectionString)
Dim da As SqlDataAdapter = New SqlDataAdapter(sqlCmd, conn)
Dim ds As DataSet = New DataSet()
Try
conn.Open()
da.Fill(ds, startRecord, maxRecords, "Employees")
Catch e As SqlException
' Handle exception.
Finally
conn.Close()
End Try
Return ds.Tables("Employees")
End Function
Public Function SelectCount() As Integer
Dim conn As SqlConnection = New SqlConnection(_connectionString)
Dim cmd As SqlCommand = New SqlCommand("SELECT COUNT(*) FROM Employees", conn)
Dim result As Integer = 0
Try
conn.Open()
result = CInt(cmd.ExecuteScalar())
Catch e As SqlException
' Handle exception.
Finally
conn.Close()
End Try
Return result
End Function
'''''
' Verify that only valid columns are specified in the sort expression to aSub a SQL Injection attack.
Private Sub VerifySortColumns(sortColumns As String)
If sortColumns.ToLowerInvariant().EndsWith(" desc") Then _
sortColumns = sortColumns.Substring(0, sortColumns.Length - 5)
Dim columnNames() As String = sortColumns.Split(",")
For Each columnName As String In columnNames
Select Case columnName.Trim().ToLowerInvariant()
Case "employeeid"
Case "lastname"
Case "firstname"
Case ""
Case Else
Throw New ArgumentException("SortColumns contains an invalid column name.")
End Select
Next
End Sub
' Select an employee.
Public Function GetEmployee(EmployeeID As Integer) As DataTable
Dim conn As SqlConnection = New SqlConnection(_connectionString)
Dim da As SqlDataAdapter = _
New SqlDataAdapter("SELECT EmployeeID, LastName, FirstName, Address, City, Region, PostalCode " & _
" FROM Employees WHERE EmployeeID = @EmployeeID", conn)
da.SelectCommand.Parameters.Add("@EmployeeID", SqlDbType.Int).Value = EmployeeID
Dim ds As DataSet = New DataSet()
Try
conn.Open()
da.Fill(ds, "Employees")
Catch e As SqlException
' Handle exception.
Finally
conn.Close()
End Try
Return ds.Tables("Employees")
End Function
' Delete the Employee by ID.
Public Function DeleteEmployee(EmployeeID As Integer) As Integer
Dim conn As SqlConnection = New SqlConnection(_connectionString)
Dim cmd As SqlCommand = New SqlCommand("DELETE FROM Employees WHERE EmployeeID = @EmployeeID", conn)
cmd.Parameters.Add("@EmployeeID", SqlDbType.Int).Value = EmployeeID
Dim result As Integer = 0
Try
conn.Open()
result = cmd.ExecuteNonQuery()
Catch e As SqlException
' Handle exception.
Finally
conn.Close()
End Try
Return result
End Function
' Update the Employee by original ID.
Public Function UpdateEmployee(EmployeeID As Integer, LastName As String, FirstName As String, _
Address As String, City As String, Region As String, _
PostalCode As String) As Integer
If String.IsNullOrEmpty(FirstName) Then _
Throw New ArgumentException("FirstName cannot be null or an empty string.")
If String.IsNullOrEmpty(LastName) Then _
Throw New ArgumentException("LastName cannot be null or an empty string.")
If Address Is Nothing Then Address = String.Empty
If City Is Nothing Then City = String.Empty
If Region Is Nothing Then Region = String.Empty
If PostalCode Is Nothing Then PostalCode = String.Empty
Dim conn As SqlConnection = New SqlConnection(_connectionString)
Dim cmd As SqlCommand = New SqlCommand("UPDATE Employees " & _
" SET FirstName=@FirstName, LastName=@LastName, " & _
" Address=@Address, City=@City, Region=@Region, " & _
" PostalCode=@PostalCode " & _
" WHERE EmployeeID=@EmployeeID", conn)
cmd.Parameters.Add("@FirstName", SqlDbType.VarChar, 10).Value = FirstName
cmd.Parameters.Add("@LastName", SqlDbType.VarChar, 20).Value = LastName
cmd.Parameters.Add("@Address", SqlDbType.VarChar, 60).Value = Address
cmd.Parameters.Add("@City", SqlDbType.VarChar, 15).Value = City
cmd.Parameters.Add("@Region", SqlDbType.VarChar, 15).Value = Region
cmd.Parameters.Add("@PostalCode", SqlDbType.VarChar, 10).Value = PostalCode
cmd.Parameters.Add("@EmployeeID", SqlDbType.Int).Value = EmployeeID
Dim result As Integer = 0
Try
conn.Open()
result = cmd.ExecuteNonQuery()
Catch e As SqlException
' Handle exception.
Finally
conn.Close()
End Try
Return result
End Function
' Insert an Employee.
Public Function InsertEmployee(LastName As String, FirstName As String, Address As String, _
City As String, Region As String, PostalCode As String) As Integer
If String.IsNullOrEmpty(FirstName) Then _
Throw New ArgumentException("FirstName cannot be null or an empty string.")
If String.IsNullOrEmpty(LastName) Then _
Throw New ArgumentException("LastName cannot be null or an empty string.")
If Address Is Nothing Then Address = String.Empty
If City Is Nothing Then City = String.Empty
If Region Is Nothing Then Region = String.Empty
If PostalCode Is Nothing Then PostalCode = String.Empty
Dim conn As SqlConnection = New SqlConnection(_connectionString)
Dim cmd As SqlCommand = New SqlCommand("INSERT INTO Employees " & _
" (FirstName, LastName, Address, City, Region, PostalCode) " & _
" Values(@FirstName, @LastName, @Address, @City, @Region, @PostalCode) " & _
"SELECT @EmployeeID = SCOPE_IDENTITY()", conn)
cmd.Parameters.Add("@FirstName", SqlDbType.VarChar, 10).Value = FirstName
cmd.Parameters.Add("@LastName", SqlDbType.VarChar, 20).Value = LastName
cmd.Parameters.Add("@Address", SqlDbType.VarChar, 60).Value = Address
cmd.Parameters.Add("@City", SqlDbType.VarChar, 15).Value = City
cmd.Parameters.Add("@Region", SqlDbType.VarChar, 15).Value = Region
cmd.Parameters.Add("@PostalCode", SqlDbType.VarChar, 10).Value = PostalCode
Dim p As SqlParameter = cmd.Parameters.Add("@EmployeeID", SqlDbType.Int)
p.Direction = ParameterDirection.Output
Dim newEmployeeID As Integer = 0
Try
conn.Open()
cmd.ExecuteNonQuery()
newEmployeeID = CInt(p.Value)
Catch e As SqlException
' Handle exception.
Finally
conn.Close()
End Try
Return newEmployeeID
End Function
'
' Methods that support Optimistic Concurrency checks.
'
' Delete the Employee by ID.
Public Function DeleteEmployee(original_EmployeeID As Integer, original_LastName As String, _
original_FirstName As String, original_Address As String, _
original_City As String, original_Region As String, _
original_PostalCode As String) As Integer
If String.IsNullOrEmpty(original_FirstName) Then _
Throw New ArgumentException("FirstName cannot be null or an empty string.")
If String.IsNullOrEmpty(original_LastName) Then _
Throw New ArgumentException("LastName cannot be null or an empty string.")
If original_Address Is Nothing Then original_Address = String.Empty
If original_City Is Nothing Then original_City = String.Empty
If original_Region Is Nothing Then original_Region = String.Empty
If original_PostalCode Is Nothing Then original_PostalCode = String.Empty
Dim sqlCmd As String = "DELETE FROM Employees WHERE EmployeeID = @original_EmployeeID " & _
" AND LastName = @original_LastName AND FirstName = @original_FirstName " & _
" AND Address = @original_Address AND City = @original_City " & _
" AND Region = @original_Region AND PostalCode = @original_PostalCode"
Dim conn As SqlConnection = New SqlConnection(_connectionString)
Dim cmd As SqlCommand = New SqlCommand(sqlCmd, conn)
cmd.Parameters.Add("@original_EmployeeID", SqlDbType.Int).Value = original_EmployeeID
cmd.Parameters.Add("@original_FirstName", SqlDbType.VarChar, 10).Value = original_FirstName
cmd.Parameters.Add("@original_LastName", SqlDbType.VarChar, 20).Value = original_LastName
cmd.Parameters.Add("@original_Address", SqlDbType.VarChar, 60).Value = original_Address
cmd.Parameters.Add("@original_City", SqlDbType.VarChar, 15).Value = original_City
cmd.Parameters.Add("@original_Region", SqlDbType.VarChar, 15).Value = original_Region
cmd.Parameters.Add("@original_PostalCode", SqlDbType.VarChar, 10).Value = original_PostalCode
Dim result As Integer = 0
Try
conn.Open()
result = cmd.ExecuteNonQuery()
Catch e As SqlException
' Handle exception.
Finally
conn.Close()
End Try
Return result
End Function
' Update the Employee by original ID.
Public Function UpdateEmployee(EmployeeID As Integer, LastName As String, FirstName As String, _
Address As String, City As String, Region As String, _
PostalCode As String, _
original_EmployeeID As Integer, original_LastName As String, _
original_FirstName As String, original_Address As String, _
original_City As String, original_Region As String, _
original_PostalCode As String) As Integer
If String.IsNullOrEmpty(FirstName) Then _
Throw New ArgumentException("FirstName cannot be null or an empty string.")
If String.IsNullOrEmpty(LastName) Then _
Throw New ArgumentException("LastName cannot be null or an empty string.")
If Address Is Nothing Then Address = String.Empty
If City Is Nothing Then City = String.Empty
If Region Is Nothing Then Region = String.Empty
If PostalCode Is Nothing Then PostalCode = String.Empty
If original_Address Is Nothing Then original_Address = String.Empty
If original_City Is Nothing Then original_City = String.Empty
If original_Region Is Nothing Then original_Region = String.Empty
If original_PostalCode Is Nothing Then original_PostalCode = String.Empty
Dim sqlCmd As String = "UPDATE Employees " & _
" SET FirstName = @FirstName, LastName = @LastName, " & _
" Address = @Address, City = @City, Region = @Region, " & _
" PostalCode = @PostalCode " * _
" WHERE EmployeeID = @original_EmployeeID " & _
" AND LastName = @original_LastName AND FirstName = @original_FirstName " & _
" AND Address = @original_Address AND City = @original_City " & _
" AND Region = @original_Region AND PostalCode = @original_PostalCode"
Dim conn As SqlConnection = New SqlConnection(_connectionString)
Dim cmd As SqlCommand = New SqlCommand(sqlCmd, conn)
cmd.Parameters.Add("@FirstName", SqlDbType.VarChar, 10).Value = FirstName
cmd.Parameters.Add("@LastName", SqlDbType.VarChar, 20).Value = LastName
cmd.Parameters.Add("@Address", SqlDbType.VarChar, 60).Value = Address
cmd.Parameters.Add("@City", SqlDbType.VarChar, 15).Value = City
cmd.Parameters.Add("@Region", SqlDbType.VarChar, 15).Value = Region
cmd.Parameters.Add("@PostalCode", SqlDbType.VarChar, 10).Value = PostalCode
cmd.Parameters.Add("@original_EmployeeID", SqlDbType.Int).Value = original_EmployeeID
cmd.Parameters.Add("@original_FirstName", SqlDbType.VarChar, 10).Value = original_FirstName
cmd.Parameters.Add("@original_LastName", SqlDbType.VarChar, 20).Value = original_LastName
cmd.Parameters.Add("@original_Address", SqlDbType.VarChar, 60).Value = original_Address
cmd.Parameters.Add("@original_City", SqlDbType.VarChar, 15).Value = original_City
cmd.Parameters.Add("@original_Region", SqlDbType.VarChar, 15).Value = original_Region
cmd.Parameters.Add("@original_PostalCode", SqlDbType.VarChar, 10).Value = original_PostalCode
Dim result As Integer = 0
Try
conn.Open()
result = cmd.ExecuteNonQuery()
Catch e As SqlException
' Handle exception.
Finally
conn.Close()
End Try
Return result
End Function
End Class
End Namespace