Hi!

I recently followed the link of jmcilhinney about login form and got my form working now. I have a follow up question but I think it's another concern so I decided to create this new thread.

In my login form I have the following
Code:
Imports System.Data.SqlClient
Public Class LoginForm1
    Dim cnn As New SqlConnection
    Dim cmdLogIn As New SqlCommand
    Dim daUsers As New SqlDataAdapter
    Dim builder As New SqlCommandBuilder(daUsers)

    'DataSet
    Dim dsLogIn As New DataSet
    Dim dsTeacherID As New DataSet
    Public strID As String
  
Private Sub LoginForm1_Load(ByVal sender As System.Object, ByVal e As System.EventArgs) Handles MyBase.Load
        cnn = New SqlConnection(My.MySettings.Default.MyDBConnectionString)

        If cnn.State = ConnectionState.Closed Then cnn.Open()

        cmdLogIn = cnn.CreateCommand
        cmdLogIn.CommandText = "SELECT * FROM tblTeacherFile"
        daUsers.MissingSchemaAction = MissingSchemaAction.AddWithKey

        dsLogIn.Clear()
        'dsLogIn = New DataSet
        daUsers.SelectCommand = cmdLogIn
        daUsers.Fill(dsLogIn, "tblTeacherFile")
        cboUserName.DataSource = dsLogIn.Tables("tblTeacherFile")
        cboUserName.DisplayMember = "Teacher_Name"

        txtTeacherID.Hide()
        txtTeacherID.DataBindings.Add("text", dsLogIn.Tables("tblTeacherFile"), "TeacherID")
        cnn.Close()

 Private Sub OK_Click(ByVal sender As System.Object, ByVal e As System.EventArgs) Handles OK.Click
        cmdLogIn = New SqlCommand("SELECT COUNT(*) FROM tblteacherfile WHERE Teacher_Name = @Teacher_Name AND Pswd = @Pswd", cnn)

        With cmdLogIn.Parameters
            .AddWithValue("@Teacher_Name", Me.cboUserName.Text)
            .AddWithValue("@Pswd", Me.PasswordTextBox.Text)
        End With
        strID = Me.txtTeacherID.Text
        If cnn.State = ConnectionState.Closed Then cnn.Open()

        If CInt(cmdLogIn.ExecuteScalar()) = 0 Then
            MessageBox.Show("Failed login")
        Else
            'MessageBox.Show("Successful login")
            frmMain.Show()
        End If

        'Me.Close()
    End Sub
End Class
End Sub
I would like to use the value of my variable strID in SELECT Statement I have in my frmMain like
Code:
"SELECT * FROM tblTeachersLoad WHERE TeacherID=strID"
I am not successful in doing so. I would like to use the variable value as long as my app is running. How can I achieve it?

Thanks!