Drop Down List

[drizz]

Basically I am trying to write a simple conversion tool. Take x amount of feet and convert that into y amount of meters and vice versa. I am using a whole bunch of different measurements so I decided to use two comboboxes as dropdownlists. Basically, if the user inputs 5 they can then easily select meters to feet or feet to meters, etc.

I have my equation written but can not figure out for the life of me how to assign a value or key to the items in my dropdownlist. I am using visual studio .net. I populated my list originally using the List Property. How do I give those a property? Say I want Meters to equal sngMet in my code. How would I do that?

I need to Populate the two lists, give each item in the list a unique ID, tie that id to a value and then insert that value into an equation.

If you couldn't tell by now, I am a noobie. I am just at the point that looking at this any longer will make me mad! I've tried to RTFM but its a POS.

Thanks,...

[drizz]

Here's a sample of the code I am using. The problem is that I can't call my "Item.Key" later in the program. The "Item.Value" prints fine. The "Item.Key" string comes up blank:

<vb code>
Dim mySortedList as new System.Collections.SortedList
Dim Item as DictionaryEntry

mySortedList("sngMet") = "Meters"
mySortedList("sngIn") = "Inches"
mySortedList("sngFt") = "Feet"
mySortedList("sngCm") = "Centimeters"

For each Item in mySortedList
Dim newListItem as new ListItem()
newListItem.Text = Item.Value
newListItem.Value = Item.Key
DropDownList1.Items.Add(newListItem)
Next

</vb code>


__________________
Drew

[nswan]

hi,

I don't know if this is too complicated for you as a noob but it's a way I know of getting it to work. You need to create your own class called cUnit. Here you can store your names and keys. Here's the code. Let me know if you have any questions

Dim blnFinishedLoading As Boolean = False
    Private Sub Form1_Load(ByVal sender As Object, ByVal e As System.EventArgs) Handles MyBase.Load
        Dim myArrayList As New System.Collections.ArrayList

        Dim Item As cUnit

        Item = New cUnit
        Item.key = "sngMet"
        Item.unit = "Meters"
        myArrayList.Add(Item)

        Item = New cUnit
        Item.key = "sngFeet"
        Item.unit = "Feet"
        myArrayList.Add(Item)

        ComboBox1.DataSource = myArrayList
        ComboBox1.ValueMember = "key"
        ComboBox1.DisplayMember = "unit"
        blnFinishedLoading = True
    End Sub

    Private Sub ComboBox1_SelectedIndexChanged(ByVal sender As System.Object, ByVal e As System.EventArgs) Handles ComboBox1.SelectedIndexChanged
        If blnFinishedLoading = True Then
            MessageBox.Show(ComboBox1.SelectedValue & " " & ComboBox1.Text)
        End If
    End Sub
End Class
'NOTE THIS IS THE END OF THE FORMS CLASS. IF YOU COPY AND 
'PASTE MAKE SURE YOU DON'T HAVE TOO MANY End Class LINES
'OF CODE

Public Class cUnit
    Dim strKey As String
    Dim strUnit As String

    Public Property key() As String
        Get
            Return strKey
        End Get
        Set(ByVal Value As String)
            strKey = Value
        End Set
    End Property

    Public Property unit() As String
        Get
            Return strUnit
        End Get
        Set(ByVal Value As String)
            strUnit = Value
        End Set
    End Property
end class

you can just copy and paste it right underneath the 'windows designed code' bit

Hope this helps
Nick

[drizz]

Actually that makes a lot of sense. Since my last post, I created an array and was able to get it to return the proper .SelectedIndex and .Text. So I am close... I appreciate your help. Your way makes more sense than mine though. I may rewrite using your technique. Is your technique a better way or a more accepted method?

Here is the code I am currently using:
<vbcode>
Dim strCurrency(7) As String

strCurrency(0) = "Select Currency"
strCurrency(1) = "European Euro"
strCurrency(2) = "Mexican Peso"
strCurrency(3) = "Indian Rupee"
strCurrency(4) = "British Pound"
strCurrency(5) = "Japanese Yen"
strCurrency(6) = "Canadian Dollar"
strCurrency(7) = "American Dollar"

Dim i As Integer
For i = 0 To 7
cboFrom.Items.Add(strCurrency(i))
cboTo.Items.Add(strCurrency(i))
Next i
</vbcode>

Thanks!

[nswan]

well it's using classes which is a good start. This means you can seperate out any logic you may need in the class into them. You could pass these objects created from the class around. You can seperate out your classes to seperate .dll's which can help scaleability a lot.

Using classes and OOP in .NET is the way forward but whether it's too complicated for this problem I don't know. I suppose it depends what else the application is going to do.