What's the elegant way to make sure that values of dictionary are called or set in a specific location? - vb.net

Question

Private Shared Property _dictOfCoinNameNameBasedOnMarketandSymbol As Dictionary(Of String, String)
Get
End Get
Set(value As Dictionary(Of String, String))
End Set
End Property
The usual way, if it's not a dictionary, is to turn the variable into property. Then we can put breakpoint in set and get.
The thing is setting a dictionary as property will make the compiler think I need a set method to set the dictionary. I want a set method to set an item in the property.
I want to be able to replace spread occurrences of
_dictOfCoinNameNameBasedOnMarketandSymbol("key") = "value"
into a code I can set breakpoint too. How should I?
I suppose I can just create a normal sub and replace all occurrences of _dictOfCoinNameNameBasedOnMarketandSymbol("key") = "value" into AssignCoinNameNameBasedOnMarketandSymbolWithKeyValue("key","value")
I wrote
Function GetCoinNameNameBasedOnMarketandSymbol(key As String) As String
Return _dictOfCoinNameNameBasedOnMarketandSymbol(key)
End Function
Sub AssignCoinNameNameBasedOnMarketandSymbol(key As String, coinname As String)
_dictOfCoinNameNameBasedOnMarketandSymbol(key) = coinname
End Sub
And then I will just manually all other occurrences of _dictOfCoinNameNameBasedOnMarketandSymbol. Then I can put breakpoints in AssignCoinNameNameBasedOnMarketandSymbol if I see _dictOfCoinNameNameBasedOnMarketandSymbol get assigned wrong value.
The problem with this technique is there isn't really anyway to enforce it automatically. I just have to go through the code and replace that one by one.
Are there more elegant ways?
If _dictOfCoinNameNameBasedOnMarketandSymbol is not a dictionary then changing it to property with proper get and set value would do just fine. I don't even have to change anything.

Answer 1

I think that I may have initially misinterpreted the question. I will leave my original answer below for completeness but I will answer here based on my new understanding.
It seems to me that what you actually need is an indexed property that will wrap the Dictionary, e.g.
Public Class SomeClass
Private Shared ReadOnly valuesByKey As New Dictionary(Of String, String)
Public Shared Property ValueByKey(key As String) As String
Get
Return valuesByKey(key)
End Get
Set
valuesByKey(key) = Value
End Set
End Property
End Class
You can now just get and set the ValueByKey property and never have direct access - read-only or otherwise - to the Dictionary object inside the class. You can also add whatever code you like before the Return statement in the getter and before or after the existing line of code in the setter.
ORIGINAL ANSWER:
What you want is a ReadOnly property. That's exactly how collections are exposed throughout the .NET Framework, e.g. Control.Controls, ComboBox.Items, DataSet.Tables, DataTable.Columns, DataTable.Rows, etc, etc. In your case, that would look like this:
Public Shared ReadOnly Property CoinNamesByMarketAndSymbol As New Dictionary(Of String, String)
I've taken the liberty of giving that property a sensible name. Note that this is an auto-property, i.e. one where you don't explicitly specify a getter or setter. Without using an auto-property, the equivalent code would this:
Private Shared _coinNamesByMarketAndSymbol As New Dictionary(Of String, String)
Public Shared ReadOnly Property CoinNamesByMarketAndSymbol As Dictionary(Of String, String)
Get
Return _coinNamesByMarketAndSymbol
End Get
End Property
Note that I have declared this property Public. I note that you have declared it Private but that seems to make little sense. What use could such a property be? If it should only be accessed internally then why would you not just use a field?
With the code above, you can now get the Dictionary from the property to get, add or remove items but you cannot replace the entire Dictionary, i.e. you can do this:
Dim coinName = SomeClass.CoinNamesByMarketAndSymbol(marketAndSymbol)
SomeClass.CoinNamesByMarketAndSymbol.Add(marketAndSymbol, coinName)
SomeClass.CoinNamesByMarketAndSymbol.Remove(marketAndSymbol)
But you cannot do this:
SomeClass.CoinNamesByMarketAndSymbol = New Dictionary(Of String, String)