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FeatureRefresh Method

Resets the attributes and geometry to the values in the data source

Namespace:  Esri.ArcGISRuntime.Data
Assembly:  Esri.ArcGISRuntime (in Esri.ArcGISRuntime.dll) Version: 100.7.0.0
Syntax
C#
public bool Refresh()

Return Value

Type: Boolean
If true, the geometry or attributes were updated; otherwise, false false.
Remarks
Discards any in-memory changes to the Feature that have not been applied to the table, and reloads the Feature geometry and all attributes
Examples

Android

Example Name: AddFeatures

Add features to a feature layer.

Code example screen shot.

C#
// Copyright 2019 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 Android.App;
using Android.OS;
using Android.Views;
using Android.Widget;
using Esri.ArcGISRuntime.Data;
using Esri.ArcGISRuntime.Geometry;
using Esri.ArcGISRuntime.Mapping;
using Esri.ArcGISRuntime.UI.Controls;
using System;

namespace ArcGISRuntimeXamarin.Samples.AddFeatures
{
    [Activity (ConfigurationChanges=Android.Content.PM.ConfigChanges.Orientation | Android.Content.PM.ConfigChanges.ScreenSize)]
    [ArcGISRuntime.Samples.Shared.Attributes.Sample(
        "Add features (feature service)",
        "Data",
        "Add new features to an online feature service.",
        "")]
    public class AddFeatures : Activity
    {
        // Hold a reference to the MapView.
        private MapView _myMapView;

        // URL to the feature service.
        private const string FeatureServiceUrl = "https://sampleserver6.arcgisonline.com/arcgis/rest/services/DamageAssessment/FeatureServer/0";

        // Hold a reference to the feature table.
        private ServiceFeatureTable _damageFeatureTable;

        protected override void OnCreate(Bundle bundle)
        {
            base.OnCreate(bundle);

            Title = "Add features (feature service)";

            CreateLayout();
            Initialize();
        }

        private void Initialize()
        {
            // Create the map with streets basemap.
            _myMapView.Map = new Map(Basemap.CreateStreets());

            // Create the feature table, referring to the Damage Assessment feature service.
            _damageFeatureTable = new ServiceFeatureTable(new Uri(FeatureServiceUrl));

            // Create a feature layer to visualize the features in the table.
            FeatureLayer damageLayer = new FeatureLayer(_damageFeatureTable);

            // Add the layer to the map.
            _myMapView.Map.OperationalLayers.Add(damageLayer);

            // Listen for user taps on the map - this will select the feature.
            _myMapView.GeoViewTapped += MapView_Tapped;

            // Zoom to the United States.
            _myMapView.SetViewpointCenterAsync(new MapPoint(-10800000, 4500000, SpatialReferences.WebMercator), 3e7);
        }

        private async void MapView_Tapped(object sender, GeoViewInputEventArgs e)
        {
            try
            {
                // Create the feature.
                ArcGISFeature feature = (ArcGISFeature) _damageFeatureTable.CreateFeature();

                // Get the normalized geometry for the tapped location and use it as the feature's geometry.
                MapPoint tappedPoint = (MapPoint) GeometryEngine.NormalizeCentralMeridian(e.Location);
                feature.Geometry = tappedPoint;

                // Set feature attributes.
                feature.SetAttributeValue("typdamage", "Minor");
                feature.SetAttributeValue("primcause", "Earthquake");

                // Add the feature to the table.
                await _damageFeatureTable.AddFeatureAsync(feature);

                // Apply the edits to the service.
                await _damageFeatureTable.ApplyEditsAsync();

                // Update the feature to get the updated objectid - a temporary ID is used before the feature is added.
                feature.Refresh();

                // Confirm feature addition.
                ShowMessage($"Created feature {feature.Attributes["objectid"]}", "Success!");
            }
            catch (Exception ex)
            {
                ShowMessage(ex.ToString(), "Error adding feature");
            }
        }

        private void ShowMessage(string message, string title)
        {
            // Display the message to the user.
            AlertDialog.Builder builder = new AlertDialog.Builder(this);
            builder.SetMessage(message).SetTitle(title).Show();
        }


        private void CreateLayout()
        {
            // Create a new vertical layout for the app.
            var layout = new LinearLayout(this) {Orientation = Orientation.Vertical};

            // Create the MapView.
            _myMapView = new MapView(this);

            // Create the help label.
            TextView helpLabel = new TextView(this);
            helpLabel.Text = "Tap to add features.";
            helpLabel.TextAlignment = TextAlignment.Center;
            helpLabel.Gravity = GravityFlags.Center;

            // Add the help label to the layout.
            layout.AddView(helpLabel);

            // Add the map view to the layout.
            layout.AddView(_myMapView);

            // Show the layout in the app.
            SetContentView(layout);
        }
    }
}
Examples

Xamarin Forms Android

Example Name: EditFeatureAttachments

Add, delete, and download attachments for features from a service.

Code example screen shot.

C#
// Copyright 2019 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.Geometry;
using Esri.ArcGISRuntime.Mapping;
using System;
using System.Collections.Generic;
using System.IO;
using System.Linq;
using System.Threading.Tasks;
using Xamarin.Forms;
// Custom code is needed for presenting the image picker on iOS.
#if __IOS__
using Foundation;
using UIKit;
#else
using Plugin.FilePicker;
using Plugin.FilePicker.Abstractions;
#endif

namespace ArcGISRuntimeXamarin.Samples.EditFeatureAttachments
{
    [ArcGISRuntime.Samples.Shared.Attributes.Sample(
        "Edit feature attachments",
        "Data",
        "Add, delete, and download attachments for features from a service.",
        "")]
    public partial class EditFeatureAttachments : ContentPage
    {
        // URL to the feature service.
        private const string FeatureServiceUrl = "https://sampleserver6.arcgisonline.com/arcgis/rest/services/DamageAssessment/FeatureServer/0";

        // Hold a reference to the feature layer.
        private FeatureLayer _damageLayer;

        // Hold a reference to the recently selected feature.
        private ArcGISFeature _selectedFeature;

        public EditFeatureAttachments()
        {
            InitializeComponent();
            Initialize();
        }

        private void Initialize()
        {
            // Create the map with streets basemap.
            MyMapView.Map = new Map(Basemap.CreateStreets());

            // Create the feature table, referring to the Damage Assessment feature service.
            ServiceFeatureTable damageTable = new ServiceFeatureTable(new Uri(FeatureServiceUrl));

            // Create a feature layer to visualize the features in the table.
            _damageLayer = new FeatureLayer(damageTable);

            // Add the layer to the map.
            MyMapView.Map.OperationalLayers.Add(_damageLayer);

            // Listen for user taps on the map.
            MyMapView.GeoViewTapped += MapView_Tapped;

            // Zoom to the United States.
            MyMapView.SetViewpointCenterAsync(new MapPoint(-10800000, 4500000, SpatialReferences.WebMercator), 3e7);
        }

        private async void MapView_Tapped(object sender, Esri.ArcGISRuntime.Xamarin.Forms.GeoViewInputEventArgs e)
        {
            // Clear any existing selection.
            _damageLayer.ClearSelection();
            _selectedFeature = null;

            // Reset the UI.
            AttachmentsListBox.IsEnabled = false;
            AttachmentsListBox.ItemsSource = null;
            AddAttachmentButton.IsEnabled = false;

            try
            {
                // Perform an identify to determine if a user tapped on a feature.
                IdentifyLayerResult identifyResult = await MyMapView.IdentifyLayerAsync(_damageLayer, e.Position, 2, false);

                // Do nothing if there are no results.
                if (!identifyResult.GeoElements.Any())
                {
                    return;
                }

                // Get the selected feature as an ArcGISFeature. It is assumed that all GeoElements in the result are of type ArcGISFeature.
                GeoElement tappedElement = identifyResult.GeoElements.First();
                ArcGISFeature tappedFeature = (ArcGISFeature) tappedElement;

                // Select the feature in the UI and hold a reference to the tapped feature in a field.
                _damageLayer.SelectFeature(tappedFeature);
                _selectedFeature = tappedFeature;

                // Load the feature.
                await tappedFeature.LoadAsync();

                // Get the attachments.
                IReadOnlyList<Attachment> attachments = await tappedFeature.GetAttachmentsAsync();

                // Populate the UI with a list of attachments that have a content type of image/jpeg.
                AttachmentsListBox.ItemsSource = attachments.Where(attachment => attachment.ContentType == "image/jpeg");
                AttachmentsListBox.IsEnabled = true;
                AddAttachmentButton.IsEnabled = true;
            }
            catch (Exception ex)
            {
                await Application.Current.MainPage.DisplayAlert("Error selecting feature", ex.ToString(), "OK");
            }
        }

        private async void AddAttachment_Click(object sender, EventArgs e)
        {
            if (_selectedFeature == null)
            {
                return;
            }

            // Adjust the UI.
            AddAttachmentButton.IsEnabled = false;
            AttachmentActivityIndicator.IsVisible = true;

            // Get the file.
            string contentType = "image/jpeg";

            try
            {
                byte[] attachmentData;
                string filename;

                // Xamarin.Plugin.FilePicker shows the iCloud picker (not photo picker) on iOS.
                // This iOS code shows the photo picker.
#if __IOS__
                Stream imageStream = await GetImageStreamAsync();
                if (imageStream == null)
                {
                    return;
                }

                attachmentData = new byte[imageStream.Length];
                imageStream.Read(attachmentData, 0, attachmentData.Length);
                filename = _filename ?? "file1.jpeg";
#else
                // Show a file picker - this uses the Xamarin.Plugin.FilePicker NuGet package.
                FileData fileData = await CrossFilePicker.Current.PickFile(new[] {".jpg", ".jpeg"});
                if (fileData == null)
                {
                    return;
                }

                if (!fileData.FileName.EndsWith(".jpg") && !fileData.FileName.EndsWith(".jpeg"))
                {
                    await Application.Current.MainPage.DisplayAlert("Try again!", "This sample only allows uploading jpg files.", "OK");
                    return;
                }

                attachmentData = fileData.DataArray;
                filename = fileData.FileName;
#endif
                // Add the attachment.
                // The contentType string is the MIME type for JPEG files, image/jpeg.
                await _selectedFeature.AddAttachmentAsync(filename, contentType, attachmentData);

                // Get a reference to the feature's service feature table.
                ServiceFeatureTable serviceTable = (ServiceFeatureTable) _selectedFeature.FeatureTable;

                // Apply the edits to the service feature table.
                await serviceTable.ApplyEditsAsync();

                // Update UI.
                _selectedFeature.Refresh();
                AttachmentsListBox.ItemsSource = await _selectedFeature.GetAttachmentsAsync();

                await Application.Current.MainPage.DisplayAlert("Success!", "Successfully added attachment", "OK");
            }
            catch (Exception exception)
            {
                await Application.Current.MainPage.DisplayAlert("Error adding attachment", exception.ToString(), "OK");
            }
            finally
            {
                // Adjust the UI.
                AddAttachmentButton.IsEnabled = true;
                AttachmentActivityIndicator.IsVisible = false;
            }
        }

        private async void DeleteAttachment_Click(object sender, EventArgs e)
        {
            AttachmentActivityIndicator.IsVisible = true;

            try
            {
                // Get the attachment that should be deleted.
                Button sendingButton = (Button) sender;
                Attachment selectedAttachment = (Attachment) sendingButton.BindingContext;

                // Delete the attachment.
                await _selectedFeature.DeleteAttachmentAsync(selectedAttachment);

                // Get a reference to the feature's service feature table.
                ServiceFeatureTable serviceTable = (ServiceFeatureTable) _selectedFeature.FeatureTable;

                // Apply the edits to the service feature table.
                await serviceTable.ApplyEditsAsync();

                // Update UI.
                _selectedFeature.Refresh();
                AttachmentsListBox.ItemsSource = await _selectedFeature.GetAttachmentsAsync();

                // Show success message.
                await Application.Current.MainPage.DisplayAlert("Success!", "Successfully deleted attachment", "OK");
            }
            catch (Exception exception)
            {
                await Application.Current.MainPage.DisplayAlert("Error deleting attachment", exception.ToString(), "OK");
            }
            finally
            {
                AttachmentActivityIndicator.IsVisible = false;
            }
        }

        private async void DownloadAttachment_Click(object sender, EventArgs e)
        {
            try
            {
                // Get a reference to the button that raised the event.
                Button sendingButton = (Button) sender;

                // Get the attachment from the button's DataContext. The button's DataContext is set by the list view.
                Attachment selectedAttachment = (Attachment) sendingButton.BindingContext;

                if (selectedAttachment.ContentType.Contains("image"))
                {
                    // Create a preview and show it.
                    ContentPage previewPage = new ContentPage();
                    previewPage.Title = "Attachment preview";
                    Image imageView = new Image();
                    Stream contentStream = await selectedAttachment.GetDataAsync();
                    imageView.Source = ImageSource.FromStream(() => contentStream);
                    previewPage.Content = imageView;
                    await Navigation.PushAsync(previewPage);
                }
                else
                {
                    await Application.Current.MainPage.DisplayAlert("Can't show attachment", "This sample can only show image attachments.", "OK");
                }
            }
            catch (Exception exception)
            {
                await Application.Current.MainPage.DisplayAlert("Error reading attachment", exception.ToString(), "OK");
            }
        }

        // Image picker implementation.
        // Xamarin.Plugin.FilePicker shows an iCloud file picker; comment this out
        // and use the cross-platform implementation if that's what you want.
        // Note: code adapted from https://docs.microsoft.com/en-us/xamarin/xamarin-forms/app-fundamentals/dependency-service/photo-picker
#if __IOS__
        private TaskCompletionSource<Stream> _taskCompletionSource;
        private UIImagePickerController _imagePicker;
        private string _filename;

        private Task<Stream> GetImageStreamAsync()
        {
            // Create and define UIImagePickerController.
            _imagePicker = new UIImagePickerController
            {
                SourceType = UIImagePickerControllerSourceType.PhotoLibrary,
                MediaTypes = UIImagePickerController.AvailableMediaTypes(UIImagePickerControllerSourceType.PhotoLibrary)
            };

            // Set event handlers.
            _imagePicker.FinishedPickingMedia += OnImagePickerFinishedPickingMedia;
            _imagePicker.Canceled += OnImagePickerCancelled;

            // Present UIImagePickerController.
            UIWindow window = UIApplication.SharedApplication.KeyWindow;
            var viewController = window.RootViewController;
            viewController.PresentModalViewController(_imagePicker, true);

            // Return Task object.
            _taskCompletionSource = new TaskCompletionSource<Stream>();
            return _taskCompletionSource.Task;
        }

        void OnImagePickerFinishedPickingMedia(object sender, UIImagePickerMediaPickedEventArgs args)
        {
            UIImage image = args.EditedImage ?? args.OriginalImage;
            _filename = args.ImageUrl.LastPathComponent;
            if (image != null)
            {
                // Convert UIImage to .NET Stream object.
                NSData data = image.AsJPEG(1);
                Stream stream = data.AsStream();

                UnregisterEventHandlers();

                // Set the Stream as the completion of the Task.
                _taskCompletionSource.SetResult(stream);
            }
            else
            {
                UnregisterEventHandlers();
                _taskCompletionSource.SetResult(null);
            }

            _imagePicker.DismissModalViewController(true);
        }

        void OnImagePickerCancelled(object sender, EventArgs args)
        {
            UnregisterEventHandlers();
            _taskCompletionSource.SetResult(null);
            _imagePicker.DismissModalViewController(true);
        }

        void UnregisterEventHandlers()
        {
            _imagePicker.FinishedPickingMedia -= OnImagePickerFinishedPickingMedia;
            _imagePicker.Canceled -= OnImagePickerCancelled;
        }
#endif
    }
}
XAML
<?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"
             xmlns:resources="clr-namespace:Forms.Resources;assembly=ArcGISRuntime"
             x:Class="ArcGISRuntimeXamarin.Samples.EditFeatureAttachments.EditFeatureAttachments">
    <RelativeLayout>
        <esriUI:MapView x:Name="MyMapView" Style="{StaticResource MapWithFormStyle}"
                        BindingContext="{x:Reference Name=ResponsiveFormContainer}" />
        <resources:ResponsiveFormContainer x:Name="ResponsiveFormContainer">
            <Grid>
                <StackLayout Orientation="Vertical">
                    <Label Text="Tap features to select."
                           HorizontalTextAlignment="Center"
                           Margin="0,0,0,5"
                           FontAttributes="Bold" />
                    <ListView x:Name="AttachmentsListBox"
                              IsEnabled="False"
                              HeightRequest="100"
                              BackgroundColor="LightGray">
                        <!-- ItemTemplate defines how each item (Attachment) is rendered. -->
                        <ListView.ItemTemplate>
                            <DataTemplate>
                                <ViewCell>
                                    <Grid>
                                        <Grid.ColumnDefinitions>
                                            <ColumnDefinition Width="*" />
                                            <ColumnDefinition Width="Auto" />
                                            <ColumnDefinition Width="Auto" />
                                        </Grid.ColumnDefinitions>
                                        <Label Text="{Binding Name}"
                                               Margin="5,0,5,0"
                                               VerticalTextAlignment="Center" />
                                        <!-- DataTemplate sets the item as the button's DataContext automatically. -->
                                        <Button Text="🔎"
                                                Grid.Column="1"
                                                VerticalOptions="End"
                                                Margin="0,0,5,0"
                                                Clicked="DownloadAttachment_Click" />
                                        <!-- These symbols are emojis. Use Win+. on Windows to open the emoji picker. -->
                                        <Button Text="🗑"
                                                Grid.Column="2"
                                                VerticalOptions="End"
                                                Clicked="DeleteAttachment_Click" />
                                    </Grid>
                                </ViewCell>
                            </DataTemplate>
                        </ListView.ItemTemplate>
                    </ListView>
                    <Button x:Name="AddAttachmentButton"
                            Text="Add attachment"
                            IsEnabled="False"
                            Margin="0,5,0,5"
                            Clicked="AddAttachment_Click" />
                    <ActivityIndicator x:Name="AttachmentActivityIndicator"
                                       IsVisible="False"
                                       IsRunning="True" />
                </StackLayout>
            </Grid>
        </resources:ResponsiveFormContainer>
    </RelativeLayout>
</ContentPage>
See Also
Additional Examples
Hyperlink to ExampleDescription
AddFeaturesAdd features to a feature layer.
EditFeatureAttachmentsAdd, delete, and download attachments for features from a service.