"Arpan" <arpan***@hotmail.com> wrote in message
news:1157747935.579364.257990@b28g2000cwb.googlegroups.com...
>A class file named "SecureDBWS.vb" exsting in
> C:\Inetpub\wwwroot\ASPX\Business folder has the following code:
>
> Imports System
> Imports System.Data
> Imports System.Data.SqlClient
> Imports System.Web.Services
> Imports System.Web.Services.Protocols
>
> Namespace DBSecuritySettingsWS
>    Public Class Authenticator : Inherits SoapHeader
>        Public UserName As String
>        Public Password As String
>    End Class
>
>    Public Class SecureDB : Inherits WebService
>        Private sqlCmd As SqlCommand
>        Private sqlConn As SqlConnection
>        Public sHeader As Authenticator
>
>        <WebMethod(), SoapHeader("sHeader")> Public Function
> QueryDB(ByVal Query As String) As DataSet
>            If (sHeader Is Nothing) Then
>                Throw New Exception("Invalid Login")
>            End If
>
>            sqlConn = New SqlConnection("Data Source=......")
>
>            Dim dSet As DataSet
>            Dim sqlDapter As SqlDataAdapter
>
>            sqlDapter = New SqlDataAdapter(Query, sqlConn)
>            dSet = New DataSet
>            sqlDapter.Fill(dSet, "tblName")
>
>            Return dSet
>        End Function
>
>        <WebMethod()> Public Function Authenticate(ByVal strUName As
> String, ByVal strPwd As String) As Boolean
>            Dim iID As Integer
>            Dim strSQL As String
>            Dim sqlReader As SqlDataReader
>
>            sqlConn = New SqlConnection("Data Source=......")
>            strSQL = "SELECT * FROM Users WHERE UserName='" & strUName
> & "' AND Password='" & strPwd & "'"
>
>            sqlCmd = New SqlCommand(strSQL, sqlConn)
>            sqlConn.Open()
>            sqlReader = sqlCmd.ExecuteReader
>
>            Do While (sqlReader.Read)
>                iID = sqlReader.GetInt32(0)
>            Loop
>
>            sqlReader.Close()
>            sqlConn.Close()
>
>            If (iID <> 0) Then
>                Return True
>            Else
>                Return False
>            End If
>        End Function
>    End Class
> End Namespace
>
> I successfully compiled the above class code to a DLL (in
> C:\Inetpub\wwwroot\ASPX\bin).
> This is the ASMX file (named SecureDB.asmx) which uses the above class
> (this ASMX file exists in C:\Inetpub\wwwroot\ASPX\WebServices folder):
>
> <%@ WebService Language="VB" Class="DBSecuritySettingsWS.SecureDB" %>
>
> Next I executed the following command in a command prompt window (at
> the C:\Inetpub\wwwroot\ASPX\WebServices prompt) to generate the proxy
> class:
>
> wsdl /l:VB http://localhost/aspx/webservices/SecureDB.vb
>
> The proxy class named SecureDB.vb was successfully created in
> C:\Inetpub\wwwroot\ASPX\WebServices folder. Now when I opened this
> proxy class file, i found that the class named SecureDB has a public
> property named AuthenticatorValue. This is the code in the
> AuthenticatorValue property:
>
> Partial Public Class SecureDB
>    ................
>    ................
>    Public Property AuthenticatorValue() As Authenticator
>        Get
>            Return Me.authenticatorValueField
>        End Get
>        Set
>            Me.authenticatorValueField = value
>        End Set
>    End Property
>    ................
>    ................
> End Class
>
> What I would like to know is where from or how is the property named
> AuthenticatorValue getting created here? Also what does the word "Me"
> mean?
>
> Using the above generated proxy class SecureDB.vb (after compiling the
> proxy class to a DLL), this is the ASPX code that first validates a
> user & then retrieves records from a database table & displays them in
> a DataGrid:
>
> Sub CheckLogin(ByVal obj As Object, ByVal ea As EventArgs)
>    Dim blnValid As Boolean
>    Dim wsSecureDB As SecureDB
>
>    wsSecureDB = New SecureDB
>
>    blnValid = wsSecureDB.Authenticate(txtUserName.Text,
> txtPassword.Text)
>
>    If Not (blnValid) Then
>        lblMessage.Text = "INVALID LOGIN"
>        pnlLogin.Visible = True
>        pnlQuery.Visible = False
>    Else
>        pnlLogin.Visible = False
>        pnlQuery.Visible = True
>    End If
> End Sub
>
> Sub GetRecords(ByVal obj As Object, ByVal ea As EventArgs)
>    Dim dSet As DataSet
>    Dim wsSecureDB As SecureDB
>    Dim wsAuthenticate As Authenticator
>
>    dSet = New DataSet
>    wsSecureDB = New SecureDB
>    wsAuthenticate = New Authenticator
>
>    wsSecureDB.AuthenticatorValue = wsAuthenticate
>
>    dSet = wsSecureDB.QueryDB(txtQuery.Text)
>    dgQuery.DataSource = dSet
>    dgQuery.DataMember = "tblName"
>
>    dgQuery.DataBind()
> End Sub
>
> The ASPX page does two things:
>
> 1. It validates whether the user is a valid user or not using the sub
> named "CheckLogin" &
>
> 2. After validating the user, the ASPX page retrieves the records based
> on the SQL query a valid user enters in a TextBox whose ID is
> "txtQuery" using the sub "GetRecords".
>
> As such, the above code works perfectly but if I comment out the line
>
> wsSecureDB.AuthenticatorValue = wsAuthenticate
>
> in the "GetRecords" sub, then when a user tries to retrieve records
> from a DB table (using any SELECT query), the ASPX page generates an
> error. First of all, what does the above line do & secondly, what is
> the value of wsSecureDB.AuthenticatorValue? Lastly, suppose I pass the
> username & password as "john" (without the quotes) who is a valid user.
> Now what is the value of the variable "sHeader" in the "QueryDB"
> function declaration code line (shown in the very first code snippet)
> which is the following line
>
> <WebMethod(), SoapHeader("sHeader")> Public Function QueryDB(ByVal
> Query As String) As DataSet
>
> Thanks,
>
> Arpan
>