getting data from list to use in code?

How about generating the array like this, where transactionList is your list of transactions:

Data = new Data(transactionList
               .Select(i => new object[] 
                       {i.Volume, i.Price, i.TermDate} as object)
               .ToArray();

Here you create multiple arrays of objects, one for each of your transaction records. Each of these arrays is treated as a single object in the final array.

Select works by mapping each element of an input IEnumerable (in your case, transactionList), to a function of the element. In your case, your function (the lambda expression inside the Select statement) takes each element, and extract fields into an object array.

The whole operation returns an IEnumerable of object - but your Data constructor takes an object array. So we have to call ToArray() to convert to an object[].

Have you tried using one of the above solutions but not selecting an Array of Arrays?

Using a List<Transaction> called transactions:

    Data = new Data(transactions.Select(t => t).ToArray());

This is assuming that the transactions IEnumerable is a collection of Transaction objects, in which case you just want to select every object in the array and pass to the Data classes constructor.

Alternatively, you could also do:

    Data = new Data(transactions);

I you have a List<Transaction> object named tList, then your data line would look like this:

Data = new Data(tList
         // for each item in the list
         .Select(
        // create an array of the values we care about
          item => new object[] { item.Volume, item.Price, item.TermDate })
        // put each of those results into an array
        .ToArray());

If you have an IEnumerable of objects you can use the Linq Select method to transform it into an IEnumerable of a different type.

The Select statement takes as a parameter a lambda expression which takes one item from the source IEnumerable and returns a (usually) different type. The results of the lambda expression become the items in a new IEnumerable.

In your case, let's assume that you have a List<Transaction> called transactions that contains all of the Transaction objects you want to display in the graph. Assuming that the items in the list are already sorted into the correct order, you can use the following code to create your Data instance:

Data = new Data(
    transactions.Select(t => 
        (object)new object[] { t.Volume, t.Price, t.TermDate}
    )
    .ToArray()
)

In this code the Select method is used to convert your List<Transaction> to IEnumerable<object>, which the ToArray method then converts to object[].

If you need to you can do conversions and calculations on the data inside the lambda expression:

Data = new Data(
    transactions.Select(t => 
        (object)new object[] 
        {
            (int)t.Volume,
            (int)t.Price,
            t.TermDate.DayOfYear
        }
    )
    .ToArray()
)

(Edited to return object[] instead of object[][])