CODEWITHSUNDEEP
vb.net
deitysha
deitysha

Reputation: 21

show messagebox if select query returns no rows in vb.net

I had this problem where if select query has rows, it will pass the data to datagridview, but if the query result has no rows, messagebox will appear containing "No records for this code."

this is my code:

Private Sub txtScheduleID_KeyDown(sender As Object, e As KeyEventArgs) Handles txtScheduleID.KeyDown
    If (e.KeyCode = Keys.Space) Then

        Dim TextboxValue As String = RTrim(txtScheduleID.Text)
        Dim vals = TextboxValue.Split(" ").Last()

        sqlCon.Open()
        Try
            Dim QUERY As String

            QUERY = "SELECT [Class Schedule LINE].SchedID, ListofSubjects.[Course No.], ListofSubjects.[Descriptive Title], Section.Section, Curriculum.[Lab.] + Curriculum.[Lec.], UtlyTIMETable.[FROM Time] +'-'+ UtlyTIMETable.[TO Time] + '   ' + UtlyDAY.Day + '   ' + UtlyRoom.Building + ' ' +UtlyRoom.[Room No.], UtlyInstructor.[Last Name] + ', ' + LEFT (UtlyInstructor.[First Name],1)+'.' " &
                    "FROM   [Class Schedule LINE] INNER JOIN Curriculum ON [Class Schedule LINE].[Subject Code] = Curriculum.[Subject Code] INNER JOIN ListofSubjects ON Curriculum.SubjectID = ListofSubjects.SubjectID INNER JOIN Section ON [Class Schedule LINE].Section = Section.SectionID INNER JOIN UtlyTIMETable ON [Class Schedule LINE].TimeID = UtlyTIMETable.TimeID INNER JOIN UtlyDAY ON [Class Schedule LINE].DayID = UtlyDAY.DayID INNER JOIN UtlyRoom ON [Class Schedule LINE].RoomID = UtlyRoom.RoomID INNER JOIN UtlyInstructor ON [Class Schedule LINE].InstructorID = UtlyInstructor.IntructorID " &
                    "WHERE  ([Class Schedule LINE].SchedID =  '" + vals + "') "
            CMD = New SqlCommand(QUERY, sqlCon)
            Reader = CMD.ExecuteReader
            While Reader.Read
                table.Rows.Add(Reader.GetInt32(0), Reader.GetString(1), Reader.GetString(2), Reader.GetString(3), Reader.GetDecimal(4), Reader.GetString(5), Reader.GetString(6))
                dgvSubjectsEnrolled.DataSource = table
            End While
        Catch ex As Exception
            MessageBox.Show(ex.Message)
        End Try
        sqlCon.Close()
    End If
End Sub

Please edit my code. thanks

Upvotes: 0

Views: 63

Answers (1)

Mary
Mary

Reputation: 15091

It is not an error for a reader to not have rows.

If Reader.HasRows Then
 While Reader.Read
'Your code
Else
MessageBox.Show()
End If

How about putting your connection.Close in a Finally block so you are sure it will close even if there is an error. Check its state first.

Upvotes: 1

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