Question

I’m confused while trying to bind some properties housed inside a collection rather than the properties of the elements.
I’m not even sure how to phrase it right… code might explain better: here are the types (not actual code, I’ve shortened it to the basics):

public class myType
{
    public int P {get;set;}
}
public class myTypeCollection : ObservableCollection<myType>
{
    public int Ptotal {get { return this.Items.Select(i=>i.P).Aggregate((c,t)=>t = t + c); }}
    public int Pmin { get { this.Items.Min(i => i.P); } } //concept
    public int Pmax { get { this.Items.Max(i => i.P); } } //concept
}

They’re being used in a templated control, whose XAML looks like this:
(adding comments to make it as clear as i’m able to)

<!-- myGridObject = new myTemplatedControl(); -->
<!-- myGridObject.DataContext = new myTypeCollection(); -->
<!-- NOTE: collection obviously is NOT empty in the real code -->
<sdk:DataGrid ItemsSource={Binding DataContext}> 
    <sdk:DataGridTemplateColumn Width="Auto">
        <sdk:DataGridTemplateColumn.HeaderStyle>
            <Style TargetType="sdk:DataGridColumnHeader">
                <Setter Property="ContentTemplate">
                    <Setter.Value>
                        <DataTemplate>

                            <!-- ?????? write out Ptotal in the header of the column ??????? -->
                            <!-- This throws a binding-related ArgumentException -->
                            <TextBlock Text="{Binding ???? Ptotal ?????}" />

    <!-- closing tags cut off -->
    <sdk:DataGridTemplateColumn.CellTemplate>
        <DataTemplate>
            <TextBlock Text="{Binding P}" />
    <!-- closing tags cut off once more-->

{Binding P} works as expected, since P is a property of the items, but how do I access the collection’s properties like Ptotal, Pmin, etc. ?

Thanks for taking the time to read this. If any info is missing just point it out and I’ll post it.

Answer 1

Turns out the customer changed his mind about the grid headers, he doesn’t want total displayed in the header anymore.

By the way, I must have tried 20 different approached including patching in various types of converters but I haven’t been able to accomplish this not-as-simple-as-it-looks-apparently task.

Thanks again for the nonetheless interesting suggestions.