Find address

<UserControl x:Class="ArcGIS.WPF.Samples.FindAddress.FindAddress"
             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 Style="{StaticResource BorderStyle}">
            <Grid>
                <Grid.RowDefinitions>
                    <RowDefinition />
                    <RowDefinition />
                </Grid.RowDefinitions>
                <Grid.ColumnDefinitions>
                    <ColumnDefinition Width="2*" />
                    <ColumnDefinition Width="*" />
                </Grid.ColumnDefinitions>
                <TextBlock Grid.Row="0"
                           Grid.Column="0"
                           Grid.ColumnSpan="2"
                           FontWeight="SemiBold"
                           Text="Enter an address to search or select from a preset option."
                           TextAlignment="Center" />
                <ComboBox x:Name="SearchBox"
                          Grid.Row="1"
                          Grid.Column="0"
                          Margin="0,5,5,0"
                          IsEditable="True"
                          IsEnabled="False"
                          SelectionChanged="OnSuggestionChosen" />
                <Button x:Name="SearchButton"
                        Grid.Row="1"
                        Grid.Column="1"
                        Margin="0,5,0,0"
                        Click="Button_Click"
                        Content="Search"
                        IsEnabled="False" />
            </Grid>
        </Border>
    </Grid>
</UserControl>

// Copyright 2017 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 Esri.ArcGISRuntime.Symbology;
using Esri.ArcGISRuntime.Tasks.Geocoding;
using Esri.ArcGISRuntime.UI;
using Esri.ArcGISRuntime.UI.Controls;
using System;
using System.Collections.Generic;
using System.IO;
using System.Linq;
using System.Reflection;
using System.Threading.Tasks;
using System.Windows;
using System.Windows.Controls;

namespace ArcGIS.WPF.Samples.FindAddress
{
    [ArcGIS.Samples.Shared.Attributes.Sample(
        name: "Find address",
        category: "Search",
        description: "Find the location for an address.",
        instructions: "For simplicity, the sample comes loaded with a set of suggested addresses. Choose an address from the suggestions or submit your own address to show its location on the map in a callout.",
        tags: new[] { "address", "geocode", "locator", "search" })]
    [ArcGIS.Samples.Shared.Attributes.EmbeddedResource(@"PictureMarkerSymbols\pin_star_blue.png")]
    public partial class FindAddress
    {
        // Addresses for suggestion.
        private readonly string[] _addresses =
        {
            "277 N Avenida Caballeros, Palm Springs, CA",
            "380 New York St, Redlands, CA 92373",
            "Београд",
            "Москва",
            "北京"
        };

        // The LocatorTask provides geocoding services
        private LocatorTask _geocoder;

        // Service Uri to be provided to the LocatorTask (geocoder)
        private Uri _serviceUri = new Uri("https://geocode-api.arcgis.com/arcgis/rest/services/World/GeocodeServer");

        public FindAddress()
        {
            InitializeComponent();

            // Setup the control references and execute initialization
            _ = Initialize();
        }

        private async Task Initialize()
        {
            // Create new Map with basemap
            Map myMap = new Map(BasemapStyle.ArcGISImagery);

            // Provide used Map to the MapView
            MyMapView.Map = myMap;

            // Set addresses as items source
            SearchBox.ItemsSource = _addresses;

            // Enable tap-for-info pattern on results
            MyMapView.GeoViewTapped += MyMapView_GeoViewTapped;

            // Initialize the LocatorTask with the provided service Uri
            try
            {
                _geocoder = await LocatorTask.CreateAsync(_serviceUri);

                // Enable UI controls now that the LocatorTask is ready
                SearchBox.IsEnabled = true;
                SearchButton.IsEnabled = true;
            }
            catch (Exception e)
            {
                MessageBox.Show(e.ToString(), "Error");
            }
        }

        private async void UpdateSearch()
        {
            // Get the text in the search bar
            string enteredText = SearchBox.Text;

            // Clear existing marker
            MyMapView.GraphicsOverlays.Clear();

            // Return gracefully if the textbox is empty or the geocoder isn't ready
            if (String.IsNullOrWhiteSpace(enteredText) || _geocoder == null) { return; }

            try
            {
                // Get suggestions based on the input text
                IReadOnlyList<SuggestResult> suggestions = await _geocoder.SuggestAsync(enteredText);

                // Stop gracefully if there are no suggestions
                if (suggestions.Count < 1) { return; }

                // Get the full address for the first suggestion
                SuggestResult firstSuggestion = suggestions.First();
                IReadOnlyList<GeocodeResult> addresses = await _geocoder.GeocodeAsync(firstSuggestion.Label);

                // Stop gracefully if the geocoder does not return a result
                if (addresses.Count < 1) { return; }

                // Place a marker on the map - 1. Create the overlay
                GraphicsOverlay resultOverlay = new GraphicsOverlay();
                // 2. Get the Graphic to display
                Graphic point = await GraphicForPoint(addresses.First().DisplayLocation);
                // 3. Add the Graphic to the GraphicsOverlay
                resultOverlay.Graphics.Add(point);
                // 4. Add the GraphicsOverlay to the MapView
                MyMapView.GraphicsOverlays.Add(resultOverlay);

                // Update the map extent to show the marker
                MyMapView.SetViewpoint(new Viewpoint(addresses.First().Extent));
            }
            catch (Exception e)
            {
                MessageBox.Show(e.ToString(), "Error");
            }
        }

        /// <summary>
        /// Creates and returns a Graphic associated with the given MapPoint
        /// </summary>
        private async Task<Graphic> GraphicForPoint(MapPoint point)
        {
            // Hold a reference to the picture marker symbol
            PictureMarkerSymbol pinSymbol;

            // Get current assembly that contains the image
            Assembly currentAssembly = Assembly.GetExecutingAssembly();

            // Get the resource name of the blue pin image
            string resourceStreamName = this.GetType().Assembly.GetManifestResourceNames().Single(str => str.EndsWith("pin_star_blue.png"));

            // Load the blue pin resource stream
            using (Stream resourceStream = this.GetType().Assembly.
                       GetManifestResourceStream(resourceStreamName))
            {
                // Create new symbol using asynchronous factory method from stream
                pinSymbol = await PictureMarkerSymbol.CreateAsync(resourceStream);
                pinSymbol.Width = 60;
                pinSymbol.Height = 60;
                // The image is a pin; offset the image so that the pinpoint
                //     is on the point rather than the image's true center
                pinSymbol.LeaderOffsetX = 30;
                pinSymbol.OffsetY = 14;
            }

            return new Graphic(point, pinSymbol);
        }

        private void OnSuggestionChosen(object sender, SelectionChangedEventArgs e)
        {
            // Return if the user is typing.
            if (SearchBox.SelectedValue == null)
            {
                return;
            }

            // Update the search
            SearchBox.Text = SearchBox.SelectedValue.ToString();
            UpdateSearch();
        }

        private void Button_Click(object sender, System.Windows.RoutedEventArgs e)
        {
            UpdateSearch();
        }

        /// <summary>
        /// Handle tap event on the map; displays callouts showing the address for a tapped search result
        /// </summary>
        private async void MyMapView_GeoViewTapped(object sender, GeoViewInputEventArgs e)
        {
            try
            {
                // Search for the graphics underneath the user's tap
                IReadOnlyList<IdentifyGraphicsOverlayResult> results = await MyMapView.IdentifyGraphicsOverlaysAsync(e.Position, 12, false);

                // Return gracefully if there was no result
                if (results.Count < 1 || results.First().Graphics.Count < 1) { return; }

                // Reverse geocode to get addresses
                IReadOnlyList<GeocodeResult> addresses = await _geocoder.ReverseGeocodeAsync(e.Location);

                // Get the first result
                GeocodeResult address = addresses.First();
                // Use the city and region for the Callout Title
                string calloutTitle = address.Attributes["City"] + ", " + address.Attributes["Region"];
                // Use the metro area for the Callout Detail
                string calloutDetail = address.Attributes["MetroArea"].ToString();

                // Define the callout
                CalloutDefinition calloutBody = new CalloutDefinition(calloutTitle, calloutDetail);

                // Show the callout on the map at the tapped location
                MyMapView.ShowCalloutAt(e.Location, calloutBody);
            }
            catch (Exception ex)
            {
                MessageBox.Show(ex.ToString(), "Error");
            }
        }
    }
}