NullException Error help.

With the code below Im getting NullException with the If statements. Where If the user enters nothing "" then the
message box shows. Any Idea's what Im doing wrong?

Code:

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Private Sub btnOK_Click(ByVal sender As System.Object, ByVal e As System.EventArgs) Handles btnOK.Click

        Dim sUserID As String
        Dim sPass As String

        If sUserID.Trim() = "" Then

            MessageBox.Show("UserID cannot be blank," _
            & "Please endter a proper UserID.", "Error", _
            MessageBoxButtons.OK, MessageBoxIcon.Error)
            txtUserID.Select()
        Else
            If sPass.Trim() = "" Then
                MessageBox.Show("Password cannot be blank," _
                & "Please enter a proper password.", "Error", _
                MessageBoxButtons.OK, MessageBoxIcon.Error)
                txtPass.Select()
            Else
                Me.DialogResult = DialogResult.OK
            End If
        End If
    End Sub

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Wouldn't you have to get values that are contained
in the text boxes and store them in two variables then
test for empty strings? You seem to have declared two
string variables but i see nowhere in your code that
takes the data that is being held in the texboxes and
transfers it to the variables. :)

Code:

---

    Dim sUserID As String
    Dim sPass As String
    If sUserID.Trim() = "" Then

---

Doh! :D


Well, its been a long day. Atleast that's the excuse I'm
using. Thanks!

:D