database.vb

asp入门到精通的源代码

Imports System
Imports System.Data
Imports System.Data.OleDb
Imports System.Web.Services
Imports System.Web.Services.Protocols

Namespace TYASPNET

   Public Class Authenticator : Inherits SoapHeader
      Public Username as string
      Public Password as string
   End Class
   
   Public Class SecureDatabaseService : Inherits WebService
      private objConn as OleDbConnection
      private objCmd as OleDbCommand
      public sHeader as Authenticator
      
      public function <WebMethod(), SoapHeader("sHeader")> _
         SelectSQL(strSelect as string) as DataSet
         
         if sHeader is Nothing then
            throw new ArgumentNullException()
         end if
         
         if Authenticate(sHeader.UserName, sHeader.Password) _
            then
            try
               objConn = new OleDbConnection("Provider=" & _
                  "Microsoft.Jet.OLEDB.4.0;" & _
                  "Data Source=C:\ASPNET\data\banking.mdb")
               dim objDataCmd as OleDbDataAdapter = new _
                  OleDbDataAdapter(strSelect, objConn)
            
               Dim objDS as new DataSet
               objDataCmd.Fill(objDS, "tblUsers")
               return objDS
            catch ex as OleDbException
               return nothing
            end try
         end if
      end function
      
      public function <WebMethod()> ExecuteNonQuery(strQuery _
         as string) as Boolean
         try
            objConn = new OleDbConnection("Provider=" & _
               "Microsoft.Jet.OLEDB.4.0;" & _
               "Data Source=C:\ASPNET\data\banking.mdb")
            objCmd = new OleDbCommand(strQuery, objConn)
            objCmd.Connection.Open()
            objCmd.ExecuteNonQuery
            objCmd.Connection.Close()
            return true
         catch ex as OleDbException
            return false
         end try
      end function
      
      private function Authenticate(strUser as string, _
         strPass as string) as boolean
         try
            dim intID as integer = 0
            objConn = new OleDbConnection("Provider=" & _
               "Microsoft.Jet.OLEDB.4.0;" & _
               "Data Source=C:\ASPNET\data\banking.mdb")
            
            dim strSelect as string = "SELECT UserID FROM " & _
               "tblUsers WHERE Username = '" & strUser & _
               "' AND Password = '" & strPass & "'"
            objCmd = new OleDbCommand(strSelect, objConn)
            objCmd.Connection.Open()
            
            Dim objReader as OleDbDataReader
            objReader = objCmd.ExecuteReader
            do while objReader.Read
               intID = objReader.GetInt32(0)
            loop
            objReader.Close
            
            if intID <> 0 then
               return true
            else
               return false
            end if
         catch ex as OleDbException
            return false
         end try
      end function
   End Class


End Namespace