ต้องการให้มีการแสดงข้อความบอกเมื่อ หาข้อมูลไม่พบครับ

Dim connection As String = "Data Source=.\SQLEXPRESS;AttachDbFilename=|DataDirectory|\Database.mdf;Integrated Security=True;User Instance=True"
        Dim sqlroom As String
        sqlroom = "SELECT [Table-Name1].Column1, [Table-Name2].Column1,... FROM [Table-Name1],[Table-Name2] AND CUS_NAME LIKE '" & TextBox1.Text & "' "

        Dim conn As New SqlConnection(connection)
        conn.Open()
        Dim com As New SqlCommand(sqlroom, conn)
        Dim dr As SqlDataReader = com.ExecuteReader

        GridView1.DataSource = dr
        GridView1.DataBind()
        dr.Close()
        conn.Close()