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ArcGIS Runtime SDK for .NET

Create feature collection layer (Portal item)

This code sample is available for these platforms:
View Sample on GitHub

Create a feature collection layer from a portal item.

Image of create feature collection layer portal item

Use case

Feature collection layers are often used to hold features with mixed geometry or unstructured data. You can display feature collections stored in a Portal, which are often used for showing content from a CSV or map notes.

How to use the sample

The feature collection is loaded from the Portal item when the sample starts.

How it works

  1. Create a Portal.
  2. Create the PortalItem, referring to the portal and an item ID.
  3. Verify that the item represents a feature collection.
  4. Create a FeatureCollection from the item.
  5. Create a FeatureCollectionLayer, referring to the feature collection.
  6. Add the feature collection layer to the map's OperationalLayers collection.

Relevant API

  • FeatureCollection
  • FeatureCollectionLayer
  • Portal
  • PortalItem

About the data

The sample uses a sample layer depicting world populations.

Tags

collection, feature collection, feature collection layer, id, item, map notes, portal

Sample Code

<?xml version="1.0" encoding="utf-8" ?>
<ContentPage xmlns="http://xamarin.com/schemas/2014/forms"
             xmlns:x="http://schemas.microsoft.com/winfx/2009/xaml"
             xmlns:esriUI="clr-namespace:Esri.ArcGISRuntime.Xamarin.Forms;assembly=Esri.ArcGISRuntime.Xamarin.Forms"
             x:Class="ArcGISRuntime.Samples.FeatureCollectionLayerFromPortal.FeatureCollectionLayerFromPortal">

    <Grid>
        <Grid.RowDefinitions>
            <RowDefinition/>
            <RowDefinition Height="40"/>
            <RowDefinition Height="40"/>
        </Grid.RowDefinitions>
        <esriUI:MapView x:Name="MyMapView"
                        Grid.Row="0"/>
        <Entry x:Name="CollectionItemIdTextBox"
               Placeholder="Portal item Id"
               Grid.Row="1"
               HorizontalOptions="Fill"/>
        <Button Grid.Row="2"
                HorizontalOptions="Fill"
                Text="Open feature collection item"
                Clicked="OpenPortalFeatureCollectionClick"/>
    </Grid>
</ContentPage>
// Copyright 2018 Esri.
//
// Licensed under the Apache License, Version 2.0 (the "License"); you may not use this file except in compliance with the License.
// You may obtain a copy of the License at: http://www.apache.org/licenses/LICENSE-2.0
//
// Unless required by applicable law or agreed to in writing, software distributed under the License is distributed on an 
// "AS IS" BASIS, WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied. See the License for the specific 
// language governing permissions and limitations under the License.

using Esri.ArcGISRuntime.Data;
using Esri.ArcGISRuntime.Mapping;
using Esri.ArcGISRuntime.Portal;
using System;
using Xamarin.Forms;

namespace ArcGISRuntime.Samples.FeatureCollectionLayerFromPortal
{
    [ArcGISRuntime.Samples.Shared.Attributes.Sample(
        name: "Create feature collection layer (Portal item)",
        category: "Layers",
        description: "Create a feature collection layer from a portal item.",
        instructions: "The feature collection is loaded from the Portal item when the sample starts.",
        tags: new[] { "collection", "feature collection", "feature collection layer", "id", "item", "map notes", "portal" })]
    public partial class FeatureCollectionLayerFromPortal : ContentPage
    { 
        // Default portal item Id to load features from.
        private const string FeatureCollectionItemId = "32798dfad17942858d5eef82ee802f0b";

        public FeatureCollectionLayerFromPortal()
        {
            InitializeComponent();

            // call a function to initialize a map to display in the MyMapView control.
            Initialize();
        }

        private void Initialize()
        {
            // Add a default value for the portal item Id.
            CollectionItemIdTextBox.Text = FeatureCollectionItemId;

            // Create a new map with the oceans basemap and add it to the map view.
            Map myMap = new Map(Basemap.CreateOceans());
            MyMapView.Map = myMap;
        }

        private async void OpenFeaturesFromArcGISOnline(string itemId)
        {
            try
            {
                // Open a portal item containing a feature collection.
                ArcGISPortal portal = await ArcGISPortal.CreateAsync();
                PortalItem collectionItem = await PortalItem.CreateAsync(portal, itemId);

                // Verify that the item is a feature collection.
                if (collectionItem.Type == PortalItemType.FeatureCollection)
                {
                    // Create a new FeatureCollection from the item.
                    FeatureCollection featureCollection = new FeatureCollection(collectionItem);

                    // Create a layer to display the collection and add it to the map as an operational layer.
                    FeatureCollectionLayer featureCollectionLayer = new FeatureCollectionLayer(featureCollection)
                    {
                        Name = collectionItem.Title
                    };

                    MyMapView.Map.OperationalLayers.Add(featureCollectionLayer);
                }
                else
                {
                    await Application.Current.MainPage.DisplayAlert("Feature Collection", "Portal item with ID '" + itemId + "' is not a feature collection.", "OK");
                }
            }
            catch (Exception ex)
            {
                await Application.Current.MainPage.DisplayAlert("Error", "Unable to open item with ID '" + itemId + "': " + ex.Message, "OK");
            }
        }

        private async void OpenPortalFeatureCollectionClick(object sender, EventArgs e)
        {
            // Get the portal item Id from the user.
            string collectionItemId = CollectionItemIdTextBox.Text.Trim();

            // Make sure an Id was entered.
            if (String.IsNullOrEmpty(collectionItemId))
            {
                await Application.Current.MainPage.DisplayAlert("Feature Collection ID", "Please enter a portal item ID", "OK");
                return;
            }

            // Call a function to add the feature collection from the specified portal item.
            OpenFeaturesFromArcGISOnline(collectionItemId);
        }
    }
}