# .NET MAUI CollectionView LoadOnDemand Event

You can load items on demand by utilizing the `LoadOnDemand` event. The `LoadOnDemand` event handler receives two parameters:

* The `sender` argument, which is of type object, but can be cast to the `RadCollectionView` type.
* An `EventArgs` object.

## Example

The following example demonstrates a simple setup that shows how to use the event:

**1.** Create a sample model:

```C#
public class Person
{
    public string Name { get; set; }
    public int Age { get; set; }
    public Gender Gender { get; set; }
}
```

**2.** Define the CollectionView control with a `Manual` `LoadOnDemandMode` for example:

```XAML
<telerik:RadCollectionView x:Name="collectionView"
                           DisplayMemberPath="Name"
                           LoadOnDemandMode="Manual"
                           IsLoadOnDemandEnabled="True"
                           LoadOnDemand="OnLoadOnDemand"/>
```

**3.** Add the `telerik` namespace:

```XAML
xmlns:telerik="http://schemas.telerik.com/2022/xaml/maui"
```

**4.** Define sample data to the `RadCollectionView.ItemsSource`:

```C#
this.items = new ObservableCollection<Person>();

for (int i = 0; i < 20; i++)
{
    this.items.Add(new Person { Name = "Person " + i, Age = i + 10 });
}

this.collectionView.ItemsSource = this.items;
```

**5.** The `LoadOnDemand` event implementation:

```C#
private async void OnLoadOnDemand(object sender, System.EventArgs e)
{
    this.collectionView.IsLoadOnDemandActive = true;

    IEnumerable<Person> newItems = await this.GetNewItems();
    foreach (var newItem in newItems)
    {
        this.items.Add(newItem);
    }

    this.collectionView.IsLoadOnDemandActive = false;
}

private async Task<IEnumerable<Person>> GetNewItems()
{
    List<Person> newItems = new List<Person>();
    int count = this.items.Count;

    try
    {
        await Task.Delay(2000);

        for (int i = 0; i < 10; i++)
        {
            newItems.Add(new Person { Name = $"Loaded item: Person {count + i}", Age = count + i + 10 });
        }

        return newItems;
    }
    catch (Exception)
    {
        return null;
    }
}
```

This is the result:

![Telerik UI for .NET MAUI CollectionView manually loading additional Person items through the LoadOnDemand event](https://www.telerik.com/maui-ui/documentation/assets/a3fb3d55b997a13506e5ca8bbe1d112d/load-on-demand-manual-mode.gif "Telerik .NET MAUI CollectionView")

> For a runnable example demonstrating the CollectionView LoadOnDemand Event, see the [SDKBrowser Demo Application](https://www.telerik.com/maui-ui/documentation/demos-and-sample-apps/sdkbrowser-app) and go to **CollectionView > Load On Demand** category.

## See Also

* [Load On Demand Collection](https://www.telerik.com/maui-ui/documentation/controls/collectionview/load-on-demand/collection)
* [Load On Demand Command](https://www.telerik.com/maui-ui/documentation/controls/collectionview/load-on-demand/command)
* [Customize the Load On Demand Manual and Automatic Loading Indicators](https://www.telerik.com/maui-ui/documentation/controls/collectionview/load-on-demand/templates)