Text unchanged

[dr223]

Hallo,

I have a SelectedIndexChanged function, as shown below;

Private Sub CmbPayMethod_SelectedIndexChanged(ByVal sender As System.Object, ByVal e As System.EventArgs) Handles CmbPayMethod.SelectedIndexChanged
 
        Call Oracleview()
 
    End Sub

Call Oracleview Function as shown below:

Private Sub Oracleview()
        'Open the database.
        'Delete any existing record
        Dim cmd As New SqlCommand
        Dim conn As SqlConnection = GetDbConnection()
 
        'Dim a As Integer
 
        Try
            Dim Oracle_num As New System.Data.SqlClient.SqlCommand(("SELECT Oracle_no FROM gprdsql.TblOracleNos WHERE Prac_no='" & _
                            Me.TxtPracNo.Text & "' and Prac_eid = '" & _
                            Me.TxtPracEid.Text & "'  and Pay_method = '" & _
                            Me.CmbPayMethod.Text & "' "), conn)
 
            Using reader As System.Data.SqlClient.SqlDataReader = Oracle_num.ExecuteReader()
 
                While reader.Read()
 
                    Dim Oracle_no As String = FixNull(reader.GetValue(0))
 
                    TxtOracleNo.Text = Oracle_no
 
                End While
 
            End Using
 
        Catch ex As Exception
            MsgBox(ex.Message, MsgBoxStyle.Information, "GCPM")
        End Try
        
    End Sub

What I want to do is that, if the text in textbox TxtOracleNo is the same after IndexChange, i.e., a user changes from BACS to Cheque and vice versa and the Text in TxtOracleNo has not changed meaning it doesn't exit, then a message box is prompted as

MsgBox ("Enter new Oracle number").

Also, it will be nice if TxtOracleNo textbox will be empty if oracle_no is not present in TblOracleNos. Presently, if it is not available it retains the previous value.

Thanks