Btukfyl

I want to convert selected item in combobox into a number and calculate it.

I got message like this when i try to start my vb.net program.

Conversion from string "< 20 " to type 'Integer' is not valid

Any help is greatly appreciated.

this is my code:

Private Sub SaveBtn_Click(sender As Object, e As EventArgs) Handles SaveBtn.Click



    Dim LHR As Integer

    Dim TipeRetak As Integer

    Dim LbRetak As Integer

    Dim LuKer As Integer

    Dim Alur As Integer

    Dim Tambal As Integer

    Dim Kasar As Integer

    Dim amblas As Integer



    Select Case ComboLHR.SelectedIndex

        Case "< 20 "

            LHR = 0

        Case "20 - 50"

            LHR = 1

        Case "50 - 200"

            LHR = 2

        Case "200 - 500"

            LHR = 3

        Case "500 - 2000"

            LHR = 4

        Case "2000 - 5000"

            LHR = 5

        Case "5000 - 20000"

            LHR = 6

        Case "20000 - 50000"

            LHR = 7

        Case "> 50000"

            LHR = 8

    End Select



    Select Case ComboTipeRetak.SelectedIndex

        Case "Buaya"

            TipeRetak = 5

        Case "Acak"

            TipeRetak = 4

        Case "Melintang"

            TipeRetak = 3

        Case "Memanjang"

            TipeRetak = 1

        Case "Tidak Ada"

            TipeRetak = 1

    End Select



    Select Case ComboLebarRetak.SelectedIndex

        Case "> 2 mm"

            LbRetak = 3

        Case "1 - 2 mm"

            LbRetak = 2

        Case "< 1 mm"

            LbRetak = 1

        Case "Tidak Ada"

            LbRetak = 0

    End Select



    Select Case ComboLuasKerusakan.SelectedIndex

        Case "> 30%"

            LuKer = 3

        Case "10 - 30%"

            LuKer = 2

        Case "< 10%"

            LuKer = 1

        Case "0"

            LuKer = 0

    End Select



    Select Case ComboKedalamanAlur.SelectedIndex

        Case "> 20 mm"

            Alur = 7

        Case "11 - 20 mm"

            Alur = 5

        Case "6 - 10 mm"

            Alur = 3

        Case "0 - 5 mm"

            Alur = 1

        Case "Tidak Ada"

            Alur = 0

    End Select



    Select Case ComboTambal.SelectedIndex

        Case ">30 %"

            Tambal = 3

        Case "20 - 30 %"

            Tambal = 2

        Case "10 - 20%"

            Tambal = 1

        Case "< 10%"

            Tambal = 0

    End Select



    Select Case ComboKekasaran.SelectedIndex

        Case "Desintegration"

            Kasar = 4

        Case "Pelepasan Butir"

            Kasar = 3

        Case "Rough(Hungry)"

            Kasar = 2

        Case "Fatty"

            Kasar = 1

        Case "Close Texture"

            Kasar = 0

    End Select



    Select Case ComboAmblas.SelectedIndex

        Case "> 5/100 m"

            amblas = 4

        Case "2 - 5/100 m"

            amblas = 2

        Case "0 - 2/100 m"

            amblas = 1

        Case "Tidak Ada"

            amblas = 0

    End Select



    Dim comand As New MySqlCommand("INSERT INTO `tb_bnkt`(`nomor`, `Nama`, `kondisi prioritas`) VALUES (@nomor,@NamaRuas,@kondisi)", Connector)

    comand.Parameters.Add("@nomor", MySqlDbType.VarChar).Value = TextNomor.Text

    comand.Parameters.Add("@NamaRuas", MySqlDbType.VarChar).Value = ComboNamaRuas.Text

    comand.Parameters.Add("@kondisi", MySqlDbType.VarChar).Value = 17 - (Val(LHR + TipeRetak + LbRetak + LuKer + Alur + Tambal + Kasar + amblas))



    If comand.ExecuteNonQuery() = 1 Then

        MessageBox.Show("Data disimpan")

        Loading()

        TextNomor.Clear()

        ComboNamaRuas.Text = String.Empty

        ComboLHR.Text = String.Empty

        ComboTipeRetak.Text = String.Empty

        ComboLebarRetak.Text = String.Empty

        ComboLuasKerusakan.Text = String.Empty

        ComboKedalamanAlur.Text = String.Empty

        ComboTambal.Text = String.Empty

        ComboKekasaran.Text = String.Empty

        ComboAmblas.Text = String.Empty

    Else

        MessageBox.Show("Error")

    End If



End Sub

With simple class and data-binding you can simplify your code a little bid and get rid of current problem as well.

Public Class MyItem

    Public ReadOnly Name As String

    Public ReadOnly Value As Integer



    Public Sub New(name As String, value As Integer)

        Me.Name = name

        Me.Value = value

    End Sub

End Class



' Then in constructor create collection of values and bind it ot the combobox



Dim LHRValues As New List(Of MyItem) From

{

    New MyItem("< 20 ", 0),

    New MyItem("20 - 50", 1),

    New MyItem("50 - 200", 2),

    New MyItem("200 - 500", 3),

    New MyItem("500 - 2000", 4),

    New MyItem("2000 - 5000", 5),

    New MyItem("5000 - 20000", 6),

    New MyItem("20000 - 50000", 7),

    New MyItem("> 50000", 8)

}



ComboLHR.DisplayMember = "Name" ' Property Name will be used as a text

ComboLHR.ValueMember = "Value" ' Property Value will be used as a value

ComboLHR.DataSource = LHRValues



' Then in the code where you need selected value



Private Sub SaveBtn_Click(sender As Object, e As EventArgs) Handles SaveBtn.Click

    Dim selectedLHR As Integer = DirectCast(ComboLHR.SelectedValue, Integer)

    ' Other selected values

End Sub

You only need to cast ComboLHR.SelectedValue to the type you expect (Integer), because SelectedValue is of type object. I hope you have Option Strict set On.