Question

I am having a problem with my variables. I am receiving the value of the variable email through an argument from an external program. When inside the For Next loop it contains the correct value but when it exits the loop it suddenly has no value. How would I go about exiting the loop and maintaining the value of the email variable.

Option Strict On

Imports MySql.Data.MySqlClient
Imports System.Runtime.Serialization

Module jrConnect

    Sub Main(ByVal cmdArgs() As String)
        Dim cs As String = "serverinfo"
        Dim conn As New MySqlConnection(cs)
        Dim entID As String
        Dim email As String

        Dim returnValue As Integer = 0

        If cmdArgs.Length > 0 Then
            For argNum As Integer = 0 To UBound(cmdArgs, 1)
                Console.Write("your email address is " & cmdArgs(argNum))
                email = cmdArgs(argNum)
                'value of email is set
            Next argNum

        End If

        Try

            conn.Open()
            Console.Write("Connected")
            Dim stm As String = "SELECT ###### FROM ###### WHERE email =" & "'" & email & "'"
            'the email variable at this point has no value

            Dim cmd As MySqlCommand = New MySqlCommand(stm, conn)
            Dim reader As MySqlDataReader = cmd.ExecuteReader()

            While reader.Read()
                entID = reader.GetString(0)
            End While
            reader.Close()

            Dim stm2 = "SELECT value FROM ###### WHERE ###### = " & entID
            Dim cmd2 As MySqlCommand = New MySqlCommand(stm2, conn)
            Dim reader2 As MySqlDataReader = cmd2.ExecuteReader()
            Dim counter As Integer = 0

            While reader2.Read() And counter < 3
                Console.WriteLine(reader2.GetString(0) & "%")
                counter = counter + 1
            End While
            reader.Close()

        Catch ex As MySqlException
        Finally
            conn.Close()
        End Try

    End Sub

End Module

the error im getting….
http://hostthenpost.org/uploads/a66f3efbf2eba24cef0f4e8536111b54.png

I changed it up a bit and added all the db processes to a function and tried to just pass the email variable to the function but it is printing the email address but not sending it to the function. Here is the new code.

Option Strict Off

Imports MySql.Data.MySqlClient
Imports System.Runtime.Serialization

Module jrConnect

    Sub Main(ByVal cmdArgs() As String)
        Dim temp As String = "[e-mail]"
        'MsgBox("The Main procedure is starting the application.")
        Dim returnValue As Integer = 0
        ' See if there are any arguments.
        If cmdArgs.Length > 0 Then
            temp = cmdArgs(0)
            Console.Write(temp & " IN VB!")
            DBConnect(temp)
        End If
        ' Insert call to appropriate starting place in your code.
        'MsgBox("The application is terminating.")




    End Sub

    Function DBConnect(ByVal email As String)

        Dim cs As String = "serverinfo"
        Dim conn As New MySqlConnection(cs)
        Dim entID As String
        Try

            conn.Open()
            Dim stm As String = "SELECT ****** FROM ******** WHERE email =" & "'" & email & "'"
            Dim cmd As MySqlCommand = New MySqlCommand(stm, conn)
            Dim reader As MySqlDataReader = cmd.ExecuteReader()

            While reader.Read()
                entID = reader.GetString(0)
            End While
            reader.Close()

            Dim stm2 = "SELECT value FROM ****** WHERE ****** = " & entID
            Dim cmd2 As MySqlCommand = New MySqlCommand(stm2, conn)
            Dim reader2 As MySqlDataReader = cmd2.ExecuteReader()
            Dim counter As Integer = 0

            While reader2.Read() And counter < 3
                Console.WriteLine(reader2.GetString(0) & "%")
                counter = counter + 1
            End While
            reader.Close()

        Catch ex As MySqlException
        Finally
            conn.Close()
        End Try
        Return 0
    End Function
End Module

Answer 1

You don’t exit the loop when the variable is set.

Try this:

Dim email As String = "[e-mail]"
For argNum As Integer = 0 To UBound(cmdArgs, 1)
    Console.Write("your email address is " & cmdArgs(argNum))
    email = cmdArgs(argNum)
    'value of email is set
    Exit For
Next argNum

or the equivalent:

Dim email As String = "[e-mail]"
If cmdArgs.Length > 0 Then
    Console.Write("your email address is " & cmdArgs(0))
    email = cmdArgs(0)
End If