Error Handling for OpenDialog

I am trying to put up an error MessageBox when the user clicks Open without defining a file to open. In the code below, the Error box does show up until after you close the OpenDialog window. I am trying to make it so that if nothing is selected, the Error Box is displayed, more as a warning. When the Message box comes down, the User can enter a file to open. Something is wrong in this code. Any guesses what it is?


Private Sub MenuItem2_Click(ByVal sender As System.Object, ByVal e As System.EventArgs) Handles MenuItem2.Click
'The following section of code displays the directory tree and displays the
'selected filename in the textbox.

If OpenFileDialog1.ShowDialog() = DialogResult.OK Then
'put filename in textbox1

FileName.Text = OpenFileDialog1.FileName
'open file


ElseIf Not OpenFileDialog1.ShowDialog() = DialogResult.OK Then
MessageBox.Show("Choose a file to Open", "Error", MessageBoxButtons.OK, MessageBoxIcon.Error)
End If
Dim sr As New IO.StreamReader(New IO.FileStream(OpenFileDialog1.FileName, IO.FileMode.Open))
FullText.Text = sr.ReadToEnd
'Reads the entire file using StreamReader, and puts it in a textbox.

sr.Close()
End Sub