So how does the control match each item its graphing to the color? 

How does it know which is color /brush is available?

I know it's not just by the index, because when it gets to an item that is not being mapped, say item[0] is <= 0, it will not use Brush[0], and if Item[1] > 0 it will use Brush[0].

Is there another way to associate an item to a brush?

Hello,

I can say that the first item from the ItemsSource gets the first color from the Brushes collection (if it is not <=0, which means it is displayed in the chart).

When I refer to items not being mapped, I'm referring to items that will not be graphed because they have a negative or zero value.  These items don't seem to use a color.  So if I have 4 items in my ringSeries.ItemsSource with four model objects that have GrossSales.YearToDate values as follows: 0, 5, 130 and 800.  The code below basically gets a color for each item and adds it to the new brushcollection if the value is greater than 0. 

So the color for 0 is supposed to be blue, the color for 5 is supposed to be aqua, 130 is supposed to be black and the 800 is supposed to be red.  The brushcollection ends up having 3 colors in it: aqua, black and red.  But when the graph appears the colors do not match, the 5 is red, the 130 is aqua and the 800 is black.   

I have basically put a sample in the original post but here it is again: 

XAML:

<ig:XamDoughnutChart Grid.Column="1" Grid.Row="0" x:Name="GrossSalesDoughnutChart">
<ig:XamDoughnutChart.Series>
<ig:RingSeries ItemsSource="{Binding Model}" ValueMemberPath="GrossSales.YearToDate" x:Name="GrossSalesDoughnutSeries" PropertyUpdated="DoughnutSeries_OnPropertyUpdated"/>
</ig:XamDoughnutChart.Series>
</ig:XamDoughnutChart>

XAML.cs:

private void DoughnutSeries_OnPropertyUpdated(object sender, PropertyUpdatedEventArgs e)
{
if (e.PropertyName == "ItemsSource")
UpdateColors(sender as RingSeries);
}

private void UpdateColors(RingSeries ringSeries)
{
var items = ringSeries.ItemsSource as FinancialItemModelList;

if (items == null) return;

var brushes = new BrushCollection();

foreach (var item in items)
{
decimal value = 0;

if (ringSeries == GrossSalesDoughnutSeries)
value = item.GrossSales.YearToDate;

if (value <= 0) continue;

var brush = GetColorForProduct(item.Code);

if(brush != null)
brushes.Add(brush);
}

ringSeries.Brushes = brushes;
}

Hello,

I am not sure that I fully understood your question. Could you please be more specific what do you mean when you said that an item is not mapped? It will be very helpful if you send us a sample, where this is reproduced, so I can investigate it further for you.

Looking forward for your reply.