title: How to get rid of "The connection was not closed. The connection's current state is open." error?
body: <p>i have this code that everytime i run, this error comes out;</p>
  
  <pre><code> "The connection was not closed. The connection's current state is open." 
  </code></pre>
  
  <p>Eventhough i had already closed the connection. here is the code below</p>
  
  <pre><code>Private Sub cmbInstructorID_SelectedIndexChanged(sender As Object, e As EventArgs) Handles cmbInstructorID.SelectedIndexChanged
      Try
          sqlCon.Open()
          Dim QUERY As String
          QUERY = "SELECT IntructorID, [Last Name] + ', ' + [First Name] + ' ' + LEFT([First Name],1)+'.' FROM UtlyInstructor WHERE IntructorID = '" &amp; cmbInstructorID.Text &amp; "'"
          CMD = New SqlCommand(QUERY, sqlCon)
          Reader = CMD.ExecuteReader
          While Reader.Read
              cmbInstructorName.Text = Reader.GetString(1)
          End While
          sqlCon.Close()
      Catch ex As Exception
          MessageBox.Show(ex.Message)
      End Try
  End Sub
  </code></pre>
  
  <p>How do i get rid of it?</p>