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Item Class

Base class for PortalItem and LocalItem
Inheritance Hierarchy

Namespace:  Esri.ArcGISRuntime.Portal
Assembly:  Esri.ArcGISRuntime (in Esri.ArcGISRuntime.dll) Version: 100.11.0
Syntax
public abstract class Item : INotifyPropertyChanged

The Item type exposes the following members.

Constructors
  NameDescription
Protected methodItem Obsolete.
Initializes a new instance of the Item class.
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Properties
  NameDescription
Public propertyAccessInformation
Gets or sets the information on the source of the item.
Public propertyCreated
Gets the date the item was created.
Public propertyDescription
Gets or sets the detailed description of the item.
Public propertyExtent
Gets or sets the bounding extent of the item (in geographical coordinates)
Public propertyCode exampleItemId
Gets or sets the unique id for this item.
Public propertyCode exampleModified
Gets the date the item was modified.
Public propertyName
Gets the name of the item
Public propertySnippet
Gets or sets the summary description of the item.
Public propertySpatialReferenceName
Gets or sets the item's spatial reference name.
Public propertyTags
Gets the mutable list of user defined tags that are words or short phrases that describe the item.
Public propertyTermsOfUse
Gets or sets the terms of use of the item.
Public propertyCode exampleThumbnail
Gets this item's thumbnail image.
Public propertyCode exampleThumbnailUri
Gets the URI associated with the thumbnail image for this item.
Public propertyCode exampleTitle
Gets or sets the item title. This is the name that is displayed to users and by which they refer to the item. Every item must have a title.
Public propertyTypeKeywords
Gets the mutable list of keywords that further describes the type of this item. Each item is tagged with a set of type keywords that are derived based on its primary type. Update this list only if you wish to add additional type keywords.
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Methods
  NameDescription
Public methodGetDataAsync
Gets the item data. The data component of an item (the "item file") is used to stream the actual data represented by the item to the client. This resource is available only for the file and text item types.
Public methodCode exampleSetThumbnail
Sets the thumbnail for this item from the given data stream.
Public methodUpdateItemPropertiesAsync
Executes an asynchronous operation to update any item properties that have been changed.
Public methodUpdateItemPropertiesAsync(CancellationToken)
Executes an asynchronous operation to update any item properties that have been changed.
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Events
  NameDescription
Public eventPropertyChanged
Occurs when a property value changes.
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Examples

WPF

Example Name: GenerateOfflineMap

Take a web map offline.

Code example screen shot.

C#
// 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.Geometry;
using Esri.ArcGISRuntime.Mapping;
using Esri.ArcGISRuntime.Portal;
using Esri.ArcGISRuntime.Security;
using Esri.ArcGISRuntime.Symbology;
using Esri.ArcGISRuntime.Tasks;
using Esri.ArcGISRuntime.Tasks.Offline;
using Esri.ArcGISRuntime.UI;
using System;
using System.Collections.Generic;
using System.IO;
using System.Linq;
using System.Threading.Tasks;
using System.Windows;
using System.Windows.Controls;
using System.Windows.Navigation;
using System.Windows.Threading;

namespace ArcGISRuntime.WPF.Samples.GenerateOfflineMap
{
    [ArcGISRuntime.Samples.Shared.Attributes.Sample(
        name: "Generate offline map",
        category: "Map",
        description: "Take a web map offline.",
        instructions: "When the app starts, you will be prompted to sign in using a free ArcGIS Online account. Once the map loads, zoom to the extent you want to take offline. The red border shows the extent that will be downloaded. Click the \"Take Map Offline\" button to start the offline map job. The progress bar will show the job's progress. When complete, the offline map will replace the online map in the map view.",
        tags: new[] { "download", "offline", "save", "web map" })]
    public partial class GenerateOfflineMap
    {
        // The job to generate an offline map.
        private GenerateOfflineMapJob _generateOfflineMapJob;

        // The extent of the data to take offline.
        private Envelope _areaOfInterest = new Envelope(-88.1541, 41.7690, -88.1471, 41.7720, SpatialReferences.Wgs84);

        // The ID for a web map item hosted on the server (water network map of Naperville IL).
        private string WebMapId = "acc027394bc84c2fb04d1ed317aac674";

        public GenerateOfflineMap()
        {
            InitializeComponent();

            // Load the web map, show area of interest, restrict map interaction, and set up authorization. 
            Initialize();
        }

        private async void Initialize()
        {
            try
            {
                // Call a function to set up the AuthenticationManager for OAuth.
                SetOAuthInfo();

                // Create the ArcGIS Online portal.
                ArcGISPortal portal = await ArcGISPortal.CreateAsync();

                // Get the Naperville water web map item using its ID.
                PortalItem webmapItem = await PortalItem.CreateAsync(portal, WebMapId);

                // Create a map from the web map item.
                Map onlineMap = new Map(webmapItem);

                // Display the map in the MapView.
                MyMapView.Map = onlineMap;

                // Disable user interactions on the map (no panning or zooming from the initial extent).
                MyMapView.InteractionOptions = new MapViewInteractionOptions
                {
                    IsEnabled = false
                };

                // Create a graphics overlay for the extent graphic and apply a renderer.
                SimpleLineSymbol aoiOutlineSymbol = new SimpleLineSymbol(SimpleLineSymbolStyle.Solid, System.Drawing.Color.Red, 3);
                GraphicsOverlay extentOverlay = new GraphicsOverlay
                {
                    Renderer = new SimpleRenderer(aoiOutlineSymbol)
                };
                MyMapView.GraphicsOverlays.Add(extentOverlay);

                // Add a graphic to show the area of interest (extent) that will be taken offline.
                Graphic aoiGraphic = new Graphic(_areaOfInterest);
                extentOverlay.Graphics.Add(aoiGraphic);

                // Hide the map loading progress indicator.
                loadingIndicator.Visibility = Visibility.Collapsed;

                // When the map view unloads, try to clean up existing output data folders.
                MyMapView.Unloaded += (s, e) => 
                {
                    // Find output mobile map folders in the temp directory.
                    string[] outputFolders = Directory.GetDirectories(Environment.ExpandEnvironmentVariables("%TEMP%"), "NapervilleWaterNetwork*");

                    // Loop through the folder names and delete them.
                    foreach (string dir in outputFolders)
                    {
                        try
                        {
                            // Delete the folder.
                            Directory.Delete(dir, true);
                        }
                        catch (Exception)
                        {
                            // Ignore exceptions (files might be locked, for example).
                        }
                    }
                };
            }
            catch (Exception ex)
            {
                MessageBox.Show(ex.ToString(), "Error loading map");
            }
        }

        private async void TakeMapOfflineButton_Click(object sender, RoutedEventArgs e)
        {
            // Create a new folder for the output mobile map.
            string packagePath = Path.Combine(Environment.ExpandEnvironmentVariables("%TEMP%"), @"NapervilleWaterNetwork");
            int num = 1;
            while (Directory.Exists(packagePath))
            {
                packagePath = Path.Combine(Environment.ExpandEnvironmentVariables("%TEMP%"), @"NapervilleWaterNetwork" + num.ToString());
                num++;
            }

            // Create the output directory.
            Directory.CreateDirectory(packagePath);

            try
            {
                // Show the progress indicator while the job is running.
                busyIndicator.Visibility = Visibility.Visible;

                // Create an offline map task with the current (online) map.
                OfflineMapTask takeMapOfflineTask = await OfflineMapTask.CreateAsync(MyMapView.Map);

                // Create the default parameters for the task, pass in the area of interest.
                GenerateOfflineMapParameters parameters = await takeMapOfflineTask.CreateDefaultGenerateOfflineMapParametersAsync(_areaOfInterest);

                // Create the job with the parameters and output location.
                _generateOfflineMapJob = takeMapOfflineTask.GenerateOfflineMap(parameters, packagePath);

                // Handle the progress changed event for the job.
                _generateOfflineMapJob.ProgressChanged += OfflineMapJob_ProgressChanged;

                // Await the job to generate geodatabases, export tile packages, and create the mobile map package.
                GenerateOfflineMapResult results = await _generateOfflineMapJob.GetResultAsync();

                // Check for job failure (writing the output was denied, e.g.).
                if (_generateOfflineMapJob.Status != JobStatus.Succeeded)
                {
                    MessageBox.Show("Generate offline map package failed.", "Job status");
                    busyIndicator.Visibility = Visibility.Collapsed;
                }

                // Check for errors with individual layers.
                if (results.LayerErrors.Any())
                {
                    // Build a string to show all layer errors.
                    System.Text.StringBuilder errorBuilder = new System.Text.StringBuilder();
                    foreach (KeyValuePair<Layer, Exception> layerError in results.LayerErrors)
                    {
                        errorBuilder.AppendLine(string.Format("{0} : {1}", layerError.Key.Id, layerError.Value.Message));
                    }

                    // Show layer errors.
                    string errorText = errorBuilder.ToString();
                    MessageBox.Show(errorText, "Layer errors");
                }

                // Display the offline map.
                MyMapView.Map = results.OfflineMap;

                // Apply the original viewpoint for the offline map.
                MyMapView.SetViewpoint(new Viewpoint(_areaOfInterest));

                // Enable map interaction so the user can explore the offline data.
                MyMapView.InteractionOptions.IsEnabled = true;

                // Hide the "Take map offline" button.
                takeOfflineArea.Visibility = Visibility.Collapsed;

                // Show a message that the map is offline.
                messageArea.Visibility = Visibility.Visible;
            }
            catch (TaskCanceledException)
            {
                // Generate offline map task was canceled.
                MessageBox.Show("Taking map offline was canceled");
            }
            catch (Exception ex)
            {
                // Exception while taking the map offline.
                MessageBox.Show(ex.Message, "Offline map error");
            }
            finally
            {
                // Hide the activity indicator when the job is done.
                busyIndicator.Visibility = Visibility.Collapsed;
            }
        }

        // Show changes in job progress.
        private void OfflineMapJob_ProgressChanged(object sender, EventArgs e)
        {
            // Get the job.
            GenerateOfflineMapJob job = sender as GenerateOfflineMapJob;

            // Dispatch to the UI thread.
            Dispatcher.Invoke(() =>
            {
                // Show the percent complete and update the progress bar.
                Percentage.Text = job.Progress > 0 ? job.Progress.ToString() + " %" : string.Empty;
                progressBar.Value = job.Progress;
            });
        }

        private void CancelJobButton_Click(object sender, RoutedEventArgs e)
        {
            // The user canceled the job.
            _generateOfflineMapJob.Cancel();
        }

        #region Authentication
        // Constants for OAuth-related values.
        // - The URL of the portal to authenticate with (ArcGIS Online).
        private const string ServerUrl = "https://www.arcgis.com/sharing/rest";
        // - The Client ID for an app registered with the server (the ID below is for a public app created by the ArcGIS Runtime team).
        private const string AppClientId = @"lgAdHkYZYlwwfAhC";
        // - A URL for redirecting after a successful authorization (this must be a URL configured with the app).
        private const string OAuthRedirectUrl = @"my-ags-app://auth";

        private void SetOAuthInfo()
        {
            // Register the server information with the AuthenticationManager, including the OAuth settings.
            ServerInfo serverInfo = new ServerInfo
            {
                ServerUri = new Uri(ServerUrl),
                TokenAuthenticationType = TokenAuthenticationType.OAuthImplicit,
                OAuthClientInfo = new OAuthClientInfo
                {
                    ClientId = AppClientId,
                    RedirectUri = new Uri(OAuthRedirectUrl)
                }
            };

            // Register this server with AuthenticationManager.
            AuthenticationManager.Current.RegisterServer(serverInfo);

            // Use the custom OAuthAuthorize class (defined in this module) to handle OAuth communication.
            AuthenticationManager.Current.OAuthAuthorizeHandler = new OAuthAuthorize();

            // Use a function in this class to challenge for credentials.
            AuthenticationManager.Current.ChallengeHandler = new ChallengeHandler(CreateCredentialAsync);
        }

        public async Task<Credential> CreateCredentialAsync(CredentialRequestInfo info)
        {
            // ChallengeHandler function for AuthenticationManager that will be called whenever a secured resource is accessed.
            Credential credential = null;

            try
            {
                // AuthenticationManager will handle challenging the user for credentials.
                credential = await AuthenticationManager.Current.GenerateCredentialAsync(info.ServiceUri);
            }
            catch (Exception)
            {
                // Exception will be reported in calling function.
                throw;
            }

            return credential;
        }
    }

    public class OAuthAuthorize : IOAuthAuthorizeHandler
    {
        // A window to contain the OAuth UI.
        private Window _authWindow;

        // A TaskCompletionSource to track the completion of the authorization.
        private TaskCompletionSource<IDictionary<string, string>> _taskCompletionSource;

        // URL for the authorization callback result (the redirect URI configured for the application).
        private string _callbackUrl;

        // URL that handles the OAuth request.
        private string _authorizeUrl;

        // A function to handle authorization requests. It takes the URIs for the secured service, the authorization endpoint, and the redirect URI.
        public Task<IDictionary<string, string>> AuthorizeAsync(Uri serviceUri, Uri authorizeUri, Uri callbackUri)
        {
            // If the TaskCompletionSource.Task has not completed, authorization is in progress.
            if (_taskCompletionSource != null || _authWindow != null)
            {
                // Allow only one authorization process at a time.
                throw new Exception("Authorization is in progress");
            }

            // Store the authorization and redirect URLs.
            _authorizeUrl = authorizeUri.AbsoluteUri;
            _callbackUrl = callbackUri.AbsoluteUri;

            // Create a task completion source to track completion.
            _taskCompletionSource = new TaskCompletionSource<IDictionary<string, string>>();

            // Call a function to show the login controls, make sure it runs on the UI thread.
            Dispatcher dispatcher = Application.Current.Dispatcher;
            if (dispatcher == null || dispatcher.CheckAccess())
                AuthorizeOnUIThread(_authorizeUrl);
            else
            {
                Action authorizeOnUIAction = () => AuthorizeOnUIThread(_authorizeUrl);
                dispatcher.BeginInvoke(authorizeOnUIAction);
            }

            // Return the task associated with the TaskCompletionSource.
            return _taskCompletionSource.Task;
        }

        // A function to challenge for OAuth credentials on the UI thread.
        private void AuthorizeOnUIThread(string authorizeUri)
        {
            // Create a WebBrowser control to display the authorize page.
            WebBrowser authBrowser = new WebBrowser();

            // Handle the navigating event for the browser to check for a response sent to the redirect URL.
            authBrowser.Navigating += WebBrowserOnNavigating;

            // Display the web browser in a new window.
            _authWindow = new Window
            {
                Content = authBrowser,
                Height = 420,
                Width = 350,
                WindowStartupLocation = WindowStartupLocation.CenterOwner
            };

            // Set the app's window as the owner of the browser window (if main window closes, so will the browser).
            if (Application.Current != null && Application.Current.MainWindow != null)
            {
                _authWindow.Owner = Application.Current.MainWindow;
            }

            // Handle the window closed event then navigate to the authorize url.
            _authWindow.Closed += OnWindowClosed;
            authBrowser.Navigate(authorizeUri);

            // Display the Window.
            if (_authWindow != null)
            {
                _authWindow.ShowDialog();
            }
        }

        private void OnWindowClosed(object sender, EventArgs e)
        {
            // If the browser window closes, return the focus to the main window.
            if (_authWindow != null && _authWindow.Owner != null)
            {
                _authWindow.Owner.Focus();
            }

            // If the task wasn't completed, the user must have closed the window without logging in.
            if (_taskCompletionSource != null && !_taskCompletionSource.Task.IsCompleted)
            {
                // Set the task completion to indicate a canceled operation.
                _taskCompletionSource.TrySetCanceled();
            }

            _taskCompletionSource = null;
            _authWindow = null;
        }

        // Handle browser navigation (page content changing).
        private void WebBrowserOnNavigating(object sender, NavigatingCancelEventArgs e)
        {
            // Check for a response to the callback url.
            WebBrowser webBrowser = sender as WebBrowser;
            Uri uri = e.Uri;

            // If no browser, uri, or an empty url return.
            if (webBrowser == null || uri == null || _taskCompletionSource == null || String.IsNullOrEmpty(uri.AbsoluteUri))
            {
                return;
            }

            // Check if the new content is from the callback url.
            bool isRedirected = uri.AbsoluteUri.StartsWith(_callbackUrl);

            if (isRedirected)
            {
                // Cancel the event to prevent it from being handled elsewhere.
                e.Cancel = true;

                // Get a local copy of the task completion source.
                TaskCompletionSource<IDictionary<string, string>> tcs = _taskCompletionSource;
                _taskCompletionSource = null;

                // Close the window.
                if (_authWindow != null)
                {
                    _authWindow.Close();
                }

                // Call a helper function to decode the response parameters (which includes the authorization key).
                IDictionary<string, string> authResponse = DecodeParameters(uri);

                // Set the result for the task completion source.
                tcs.SetResult(authResponse);
            }
        }

        // A helper function that decodes values from a querystring into a dictionary of keys and values.
        private static IDictionary<string, string> DecodeParameters(Uri uri)
        {
            // Create a dictionary of key value pairs returned in an OAuth authorization response URI query string.
            string answer = "";

            // Get the values from the URI fragment or query string.
            if (!string.IsNullOrEmpty(uri.Fragment))
            {
                answer = uri.Fragment.Substring(1);
            }
            else
            {
                if (!string.IsNullOrEmpty(uri.Query))
                {
                    answer = uri.Query.Substring(1);
                }
            }

            // Parse parameters into key / value pairs.
            Dictionary<string, string> keyValueDictionary = new Dictionary<string, string>();
            string[] keysAndValues = answer.Split(new[] { '&' }, StringSplitOptions.RemoveEmptyEntries);
            foreach (string kvString in keysAndValues)
            {
                string[] pair = kvString.Split('=');
                string key = pair[0];
                string value = string.Empty;
                if (key.Length > 1)
                {
                    value = Uri.UnescapeDataString(pair[1]);
                }

                keyValueDictionary.Add(key, value);
            }

            // Return the dictionary of string keys/values.
            return keyValueDictionary;
        }
    }
    #endregion
}
XAML
<UserControl x:Class="ArcGISRuntime.WPF.Samples.GenerateOfflineMap.GenerateOfflineMap"
             xmlns="http://schemas.microsoft.com/winfx/2006/xaml/presentation"
             xmlns:x="http://schemas.microsoft.com/winfx/2006/xaml"
             xmlns:esri="http://schemas.esri.com/arcgis/runtime/2013">
    <Grid>
        <esri:MapView x:Name="MyMapView"/>

        <Border x:Name="takeOfflineArea" Background="White" BorderBrush="Black" BorderThickness="1"
                HorizontalAlignment="Right" VerticalAlignment="Top"
                Margin="30" Padding="20" Width="375">
            <StackPanel>
                <Button x:Name="TakeMapOfflineButton" 
                        Click="TakeMapOfflineButton_Click" 
                        IsEnabled="True" 
                        Content="Take map offline"/>
            </StackPanel>
        </Border>

        <Border x:Name="messageArea" Visibility="Collapsed"
                Background="White" BorderBrush="Black" BorderThickness="1"
                HorizontalAlignment="Right" VerticalAlignment="Top"
                Margin="30" Padding="5" Width="450">
            <StackPanel>
                <TextBlock HorizontalAlignment="Center" VerticalAlignment="Center" Margin="10"
                           FontWeight="Bold" 
                           Text="Map is offline!"/>
            </StackPanel>
        </Border>

        <Grid x:Name="busyIndicator" Background="#807f7f7f" Visibility="Collapsed">
            <Grid HorizontalAlignment="Center" VerticalAlignment="Center">
                <Grid.RowDefinitions>
                    <RowDefinition Height="auto"/>
                    <RowDefinition Height="auto"/>
                    <RowDefinition Height="auto"/>
                </Grid.RowDefinitions>
                <TextBlock HorizontalAlignment="Center" VerticalAlignment="Center" Margin="10"
                           Foreground="White" FontSize="18">
                    <Run Text="Generating offline map... "></Run>
                    <Run x:Name="Percentage" Text=""></Run>
                </TextBlock>
                <ProgressBar x:Name="progressBar"
                             Grid.Row="1" 
                             Minimum="0" Maximum="100"
                             IsEnabled="True"
                             HorizontalAlignment="Center" VerticalAlignment="Center" 
                             Width="100" Height="10" Margin="0,0,0,10"/>
                <Button x:Name="CancelJobButton" 
                        Grid.Row="3"
                        Content="Cancel" 
                        Click="CancelJobButton_Click" 
                        HorizontalAlignment="Center" 
                        Width="100"/>
            </Grid>
        </Grid>
        <Grid x:Name="loadingIndicator" 
              Background="#807f7f7f" 
              Visibility="Visible">
            <Grid HorizontalAlignment="Center" VerticalAlignment="Center">
                <Grid.RowDefinitions>
                    <RowDefinition Height="auto"/>
                    <RowDefinition Height="auto"/>
                </Grid.RowDefinitions>
                <TextBlock Text="Loading online map..." 
                           Foreground="White" FontSize="18"
                           Margin="10"/>
                <ProgressBar Grid.Row="1"
                             IsEnabled="True" IsIndeterminate="True" 
                             Width="100" Height="10" 
                             HorizontalAlignment="Center" VerticalAlignment="Center"/>
            </Grid>
        </Grid>
    </Grid>
</UserControl>
See Also
Additional Examples
Hyperlink to ExampleDescription
AuthorMapCreate and save a map as an ArcGIS `PortalItem` (i.e. web map).
DisplayKmlDisplay KML from a URL, portal item, or local KML file.
DownloadPreplannedMapTake a map offline using a preplanned map area.
FeatureCollectionLayerFromPortalCreate a feature collection layer from a portal item.
GenerateOfflineMapTake a web map offline.
GenerateOfflineMapWithOverridesTake a web map offline with additional options for each layer.
IntegratedWindowsAuthConnect to an IWA secured Portal and search for maps.
ListRelatedFeaturesList features related to the selected feature.
MapReferenceScaleSet the map's reference scale and which feature layers should honor the reference scale.
MobileMapSearchAndRouteDisplay maps and use locators to enable search and routing offline using a Mobile Map Package.
OAuthAuthenticate with ArcGIS Online (or your own portal) using OAuth2 to access secured resources (such as private web maps or layers).
OfflineBasemapByReferenceUse the `OfflineMapTask` to take a web map offline, but instead of downloading an online basemap, use one which is already on the device.
OpenScenePortalItemOpen a web scene from a portal item.
SearchPortalMapsFind webmap portal items by using a search term.
ViewContentBeneathSurfaceSee through terrain in a scene and move the camera underground.