Using combo box and stream reader

[JP1987]

Hi im trying to use a 2 combo boxes each with a list of 7 cities these need to link up with numbers in a stream reader to give a total distance if any1 can help it would be much appriciated. Below is my attempt at the code

Public Class frmDist

    Private Sub frmDist_Load(ByVal sender As System.Object, ByVal e As System.EventArgs) Handles MyBase.Load
        Dim rowcolumn(7, 7) As Integer
        Dim sr As IO.StreamReader = IO.File.OpenText("Distance.Txt")
        Dim row, col As Integer
        For row = 1 To 7
            For col = 1 To 7
                rowcolumn(row, col) = CInt(sr.ReadLine)
            Next
        Next
        sr.Close()
    End Sub

    Private Sub btnDistance_Click(ByVal sender As System.Object, ByVal e As System.EventArgs) Handles btnDistance.Click
        Dim rowcolumn(7, 7) As Integer
        Dim sr As IO.StreamReader = IO.File.OpenText("Distance.Txt")
        Dim row, col As Integer
        Dim Southampton, Edinburgh, London, Cardiff, Birmingham, Newcastle, Manchester As String
        Southampton = Convert.ToInt32(1)
        Edinburgh = Convert.ToInt32(2)
        London = Convert.ToInt32(3)
        Cardiff = Convert.ToInt32(4)
        Birmingham = Convert.ToInt32(5)
        Newcastle = Convert.ToInt32(6)
        Manchester = Convert.ToInt32(7)
        For row = 1 To 7
            For col = 1 To 7
                rowcolumn(row, col) = CInt(sr.ReadLine)
            Next
        Next
        sr.Close()
        row = (cmb1.Text)
        col = (cmb2.Text)
        If (row >= 1 And row <= 7) And (col >= 1 And col <= 7) Then
            lblDistance.Text = ("The total milage of the return journey is ") & CStr(rowcolumn(cmb1.Text, cmb2.Text)) & (" miles.")

        End If
    End Sub
End Class

[Pino]

I havent yet looked at your code, what is the problem you are having?

[JP1987]

i keep getting a large number of errors in the code that i have written and dont kno how to rectifiy them

[ForumAccount]

1) what is the contents of Distance.txt
2) what are you trying to do exactly? Your description confuses me somewhat
3) what typeof errors are you getting?

[JP1987]

contents of distance.text are the distances between cities listed in the drop down list cobo boxes. i want to select say london in 1 drop down box and manchester in the other and have the distance of that journey displayed in a label from distance.text

[ForumAccount]

How about this:

Public Class Form1 
    Private _TravelLengths As New TravelLengths 
    Public Sub New() 
        InitializeComponent() 
 
        Dim FileCnts() As String = IO.File.ReadAllLines("C:\test\Distance.txt") 
        For Each Line As String In FileCnts 
            Dim CityFrom As String = Line.Split(","c)(0) 
            Dim CityTo As String = Line.Split(","c)(1) 
            Dim Distance As Integer = CInt(Line.Split(","c)(2)) 
            Add(CityFrom, CityTo) 
            _TravelLengths.Add(CityFrom, CityTo, Distance) 
        Next 
 
    End Sub 
    Private Sub Add(ByVal CityFrom, ByVal CityTo) 
 
        If Not Me.cmbCityFrom.Items.Contains(CityFrom) Then 
            Me.cmbCityFrom.Items.Add(CityFrom) 
        End If 
        If Not Me.cmbCityFrom.Items.Contains(CityTo) Then 
            Me.cmbCityFrom.Items.Add(CityTo) 
        End If 
 
        If Not Me.cmbCityTo.Items.Contains(CityFrom) Then 
            Me.cmbCityTo.Items.Add(CityFrom) 
        End If 
        If Not Me.cmbCityTo.Items.Contains(CityTo) Then 
            Me.cmbCityTo.Items.Add(CityTo) 
        End If 
 
    End Sub 
    Private Sub btnDistance_Click(ByVal sender As System.Object, ByVal e As System.EventArgs) Handles btnDistance.Click 
        If Me.cmbCityFrom.SelectedIndex <> -1 AndAlso Me.cmbCityTo.SelectedIndex <> -1 Then 
            MessageBox.Show(Me._TravelLengths.GetDistance(Me.cmbCityFrom.SelectedItem.ToString, Me.cmbCityTo.SelectedItem.ToString)) 
        End If 
    End Sub 
    Private Class TravelLengths 
        Private _CitysFrom As New List(Of String) 
        Public Property CitysFrom() As List(Of String) 
            Get 
                Return _CitysFrom 
            End Get 
            Set(ByVal value As List(Of String)) 
                _CitysFrom = value 
            End Set 
        End Property 
        Private _CitysTo As New List(Of String) 
        Public Property CitysTo() As List(Of String) 
            Get 
                Return _CitysTo 
            End Get 
            Set(ByVal value As List(Of String)) 
                _CitysTo = value 
            End Set 
        End Property 
        Private _Distances As New List(Of Integer) 
        Public Property Distances() As List(Of Integer) 
            Get 
                Return _Distances 
            End Get 
            Set(ByVal value As List(Of Integer)) 
                _Distances = value 
            End Set 
        End Property 
        Public Function GetDistance(ByVal CityFrom As String, ByVal CityTo As String) As Integer 
            Dim i As Integer = 0 
            Do While i <> Me.CitysFrom.Count - 1 
                If (Me.CitysFrom.Item(i) = CityFrom AndAlso Me.CitysTo.Item(i) = CityTo) _ 
                            OrElse _ 
                   (Me.CitysFrom.Item(i) = CityTo AndAlso Me.CitysTo.Item(i) = CityFrom) _ 
                            Then 
                    Return Me.Distances(i) 
                End If 
                i += 1 
            Loop 
        End Function 
        Public Sub Add(ByVal CityFrom As String, ByVal CityTo As String, ByVal Distance As Integer) 
            Me.CitysFrom.Add(CityFrom) 
            Me.CitysTo.Add(CityTo) 
            Me.Distances.Add(Distance) 
        End Sub 
    End Class 
End Class

My text file looks like this:

London,Manchester,3214
London,Edinburgh,494
London,Cardiff,853
Cardiff,Manchester,634

It *IS* a little excessive since you said you only have 7 cities so you could hard code it in. But this way you could dynamically add city-to-city distances.

[JP1987]

thank you for your help, is there a way i could do it where my distance.txt file is as follows:
648
342
565
123

and have it so if i select say london to manchester it selects the relevant line from the text file and displays it in thru the label?

[ForumAccount]

How will it know what line to pick?

[JP1987]

maybe somehow assigning a value to each city that corresponds to the relevant line in the .text file or maybe using an if statement??? im not sure jus wondering if there was a way

[ForumAccount]

You mean for example: Line 1 of the text file (648) is London to Manchester? If so, then yes it is possible to do this as well. You would have to hard code it into your app though. (The relations)

[JP1987]

ok so there is no way of doing it by using a text file?

[ForumAccount]

The only way I can think of doing it without coding it, would be to keep a 1:1 relation between the lines in the text file and the item in the combobox. For example:

Item 1 in the combobox (London to Manchester) = Line 1 in the text file

Like so:

Public Class Form1 
    Private FileCnts() As String 
    Public Sub New() 
        InitializeComponent() 
        With Me.cmbCities.Items 
            .Add("London to Manchester") 
            .Add("Birmingham to London") 
        End With 
        FileCnts = IO.File.ReadAllLines("C:\test\Distance.txt") 
    End Sub 
    Private Sub btnDistance_Click(ByVal sender As System.Object, ByVal e As System.EventArgs) Handles btnDistance.Click 
        If Me.cmbCities.SelectedIndex <> -1 Then 
            MessageBox.Show(FileCnts(Me.cmbCities.SelectedIndex)) 
        End If 
    End Sub 
End Class

Text file looks like:

123
456

[JP1987]

ok thank you so much for your help and advice its much appriciated