Question

This might and impossible scenario and I may be trying to do something that I should not be doing in the first place but here it is.

I have a custom WPF Control which has two IEnumerable collections
The first collection (ItemsSource) is declared via the XAML and might be of any type of objects.
The second collection the one that I am implementing is again an IEnumerable which I want to initialize as ObservableCollection.
Here is my issue as I am restricted that both the collections are of the same type of objects (no I cannot use object as a type). For example the ItemsSource is of "MyItem" type objects and I want to initialize the second collection to be ObservableCollection().

Is this possible? Am i doing something that I should not be doing? Any hints will appreciated. On a side note if I pass the second collection via the XAML all is well, but I do not want to add such restriction to the feature I am implementing.

Edit:

Here are some code snippets to showcase the scenario: The first collection, note that this collection is inherited from the System.Windows.Controls.ItemsControl class:

public IEnumerable ItemsSource { get; set; }

The second collection:

public IEnumerable SelectedItems
{
    get
    {
        this.InitializeSelectedItemsCollectionIfRequired();
        return (IEnumerable)GetValue(SelectedItemsProperty);
    }
    set
    {
        SetValue(SelectedItemsProperty, value);
    }
}

private void InitializeSelectedItemsCollectionIfRequired()
{
    if (this.GetValue(SelectedItemsProperty) == null)
    {
        // Here is where I want to initialize the second collection if it was not already set in via a Binding in the XAML
        this.SelectedItems = new System.Collections.ObjectModel.ObservableCollection<"dont know how to pass correct type here">();
    }
}

Answer 1

由于您不知道确切的类型，因此您可以简单地恢复为最基本的类型object

this.SelectedItems = new System.Collections.ObjectModel.ObservableCollection<object>();

Initialize a collection with a type from another collection

1 个答案: