Custom Sort a column: Sort/Group/FilterMemberPath containing indexer expression

[Bas]

I'm building a way to generate columns based on an IEnumerable inside a ViewModel bound to a single row. 
When creating a cell element, the DataContext of that element is set to something based on a property path.

Consider the following example:

class Order {

       public List<OrderLine> Lines { get; }

}

 

class OrderLine {
        public int Index { get; }

      public string Data { get; }

}

• A GridViewRow would be bound to an Order object.
• For each line in this example a column will be created.

To achieve this, I created a custom column:

public override FrameworkElement CreateCellElement(GridViewCell cell, object dataItem)
{
       // more code to create item etc.
       item.SetBinding(FrameworkElement.DataContextProperty,
           new Binding(DataMemberBindingPath) { Source = dataItem });
}

The DataMemberBindingPath contains something like Lines[0] or Lines[1]. This works fine since the WPF data binding engine can handle this. When I try to define the SortMemberPath containing an Indexer, nothing happens and the expression does not seem to be parsed.

Looking at the GridViewColumn source code, there is a method of interest:

internal virtual Expression CreateSortKeyExpression(ParameterExpression parameterExpression, ExpressionBuilderOptions options)
    {
        var builder = CreateBuilder(parameterExpression, this.EffectiveSortMemberType, this.EffectiveSortMemberPath, options);

        return builder.CreateMemberAccessExpression();
    }

However the method is Internal and I cannot override this to allow working with indexers.

Is there any workaround available to override the sort behavior for a custom column?

[Dimitrina]

Hello,

You can check the possibility to define your own generic SortDescriptor and add it to RadGridView.SortDescriptors colleciton. How do you consider this option?

Regards,
Didie
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