How to get the number of rows in a row template selector - wpf - gridcontrol

I need to get the row-count of a GridControl within its RowTemplateSelector in order to change the rows template based on that number. I am trying to use the container field passed to the Select() method of the TemplateSelector.

You don't need the conatiner-object - check out this sample from the DX-docs:

public class RowTemplateSelector : DataTemplateSelector
{
    public DataTemplate EvenRowTemplate { get; set; }
    public DataTemplate OddRowTemplate { get; set; }
    public override DataTemplate SelectTemplate(object item, DependencyObject container) {

        RowData row = item as RowData; //<= mind this line of code!!!!

        if (row != null)
            return row.EvenRow ? EvenRowTemplate : OddRowTemplate;
        return base.SelectTemplate(item, container);
    }
}

Using the RowData-object you can access the corresponding View-object

DataViewBase view = row.View;

Using the View-object you can access the corresponding Grid-object

DataControlBase grid = view.DataControl;

Having access to the DataControl means you have access to its item-source

object o = grid.ItemsSource;

From there its a matter of casting and counting your actual type of ItemsSource. The following TemplateSelector returns different Templates depending on wether the item-count is smaller or bigger then ten:

public class RowTemplateSelector : DataTemplateSelector
{
    public DataTemplate SmallerThenTenTemplate { get; set; }
    public DataTemplate BiggerThenTenTemplate { get; set; }
    public override DataTemplate SelectTemplate(object item, DependencyObject container)
    {
        RowData row = item as RowData; //<= mind this line of code!!!!
        object itemSource = row.View.DataControl.ItemsSource;
        IEnumerable<YourModelType> sourceList = (IEnumerable<YourModelType>)itemSource;

        if (sourceList.Count() > 10)
            return BiggerThenTenTemplate;
        else
            return SmallerThenTenTemplate;
    }
}