How do I loop through a VB.Net array?

Question

I now do something inefficient like this:

' Returns a collection of selected choices in a multichoice field
Dim MyField As NS.ChoiceValues = CType(Me.Form.Fields("Field").Value, NS.ChoiceValues)

If MyField.Choices.Item("Value 1") IsNot Nothing Then
    ' Do stuff to database choice Value 1, which has id 100
End If

If MyField.Choices.Item("Value 1") Is Nothing Then
    ' Do other stuff to database choice Value 1, which has id 100
End If

If MyField.Choices.Item("Value 2") IsNot Nothing Then
    ' Do stuff to database choice Value 2, which has id 200
End If

If MyField.Choices.Item("Value 2") Is Nothing Then
    ' Do other stuff to database choice Value 2, which has id 200
End If

...

This is very inefficient and becomes unreadable when the number of choice values increase. So I am trying to update this:

Dim Field1Choices As New Dictionary(Of Integer, String) From { 
    {100, "Value 1"}, 
    {200, "Value 2"},
    {300, "Value 3"},
    {400, "Value 4"}
    ...
}

For Each FieldChoice As String In Field1Choices
    If MyField.Choices.Item(var_a) ' var_a should be "Value 1", "Value 2", etc.
        DoStuff.WithCoice(Me.Database, "SomeTable", var_b) 'var_b should be 100, 200 etc. 
    End If
Next

Obviously, this does not work. Because My array contains both integers and strings, For Each FieldChoice As String In Field1Choices does not work.

How can I loop through the Field1Choices array so that var_a and var_b get get the values of the array values?

A dictionary contains key-value-pairs: For Each FieldChoice As KeyValuePair(Of Integer, String) In Field1Choices Then you get the key/value like this: FieldChoice.Key and FieldChoice.Value. — Bjørn-Roger Kringsjå
– Bjørn-Roger Kringsjå, Commented Oct 2, 2014 at 16:40

Steve · Accepted Answer · 2014-10-02 16:48:39Z

2

Each entry in a Dictionary is returned as KeyValuePair type that has the property Value and the property Key.
In a For Each loop you don't need to declare the type of the iterator. It is identified correctly by the compiler looking at the type enumerated. In this case your Dictionary has an Integer key and a string value. So your KeyValuePair iterator contains a Key of type Integer and a Value of type string for every entry in the dictionary

Dim Field1Choices As New Dictionary(Of Integer, String) From { 
    {100, "Value 1"}, 
    {200, "Value 2"},
    {300, "Value 3"},
    {400, "Value 4"}
}

For Each FieldChoice In Field1Choices
    Dim var_A = FieldChoice.Value
    Console.WriteLine(var_A)

    DIm var_B = FieldChoice.Key
    Console.WriteLine(var_B)

    'DoStuff.WithCoice(Me.Database, "SomeTable", var_B) 'var_b should be 100, 200 etc. 

Next

edited Oct 2, 2014 at 16:48

answered Oct 2, 2014 at 16:42

Steve

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