Collapsing All Groups Initially in CollectionView for .NET MAUI

Environment

Version	Product	Author
10.1.0	Telerik UI for .NET MAUI CollectionView	Dobrinka Yordanova

Description

In a .NET MAUI application using the CollectionView component, I want all groups to be collapsed initially when the data is loaded. How can I achieve this behavior?

This knowledge base article also answers the following questions:

• How to start with all groups collapsed in CollectionView for .NET MAUI?
• What method collapses all groups in a CollectionView upon data load?
• Where to call the CollapseAll method in CollectionView for .NET MAUI?

Solution

To ensure that all groups are collapsed initially when the CollectionView control loads, utilize the CollapseAll method. Call this method once the data is fully loaded into the control. One effective approach is to use the CollectionView.Loaded event. However, introduce a short delay before calling CollapseAll to guarantee that data loading is complete.

Here's how you can implement this solution:

1. Subscribe to the Loaded event of the RadCollectionView. You can do this in your XAML file:

<telerik:RadCollectionView x:Name="myCollectionView" Loaded="myCollectionView_Loaded">

1. Implement the event handler in your code-behind file. In this handler, introduce a delay and then call the CollapseAll method:

private async void myCollectionView_Loaded(object sender, EventArgs e)
{
    var data = this.myCollectionView.GetDataView();
    await Task.Delay(500); // Adjust the delay as necessary.
    data.CollapseAll();
}

Note: The delay (Task.Delay(500)) might need adjustment based on the specific data loading time in your application. The key is to ensure that the data is fully loaded before calling the CollapseAll method.

See Also

• CollectionView Overview
• Grouping in CollectionView