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LocatorTaskSuggestAsync Method (String)

Retrieves a list of possible address variants for a given partial address.

Namespace:  Esri.ArcGISRuntime.Tasks.Geocoding
Assembly:  Esri.ArcGISRuntime (in Esri.ArcGISRuntime.dll) Version: 100.11.0
Syntax
public Task<IReadOnlyList<SuggestResult>> SuggestAsync(
	string searchText
)

Parameters

searchText
Type: SystemString
The partial address for which to get suggestions.

Return Value

Type: TaskIReadOnlyListSuggestResult
A task that represents the asynchronous suggestion operation. The value of the task result contains a read-only collection of SuggestResult objects.
Remarks
Geocoding suggestions provide a mechanism for implementing character-by-character auto-complete. Using a text input and optional SuggestParameters, suggested addresses can be quickly found and presented to the user. Suggestions are not limited to addresses, they can also be used for POIs (Points of Interest). To return a focused set of suggestions, set the PreferredSearchLocation or the SearchArea. Using the PreferredSearchLocation is similar to how ArcGIS Pro limits the suggestions returned.
Examples

WPF

Example Name: FindAddress

Find the location for an address.

Code example screen shot.

C#
// 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 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;
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;

namespace ArcGISRuntime.WPF.Samples.FindAddress
{
    [ArcGISRuntime.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" })]
    [ArcGISRuntime.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.arcgis.com/arcgis/rest/services/World/GeocodeServer");

        public FindAddress()
        {
            InitializeComponent();

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

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

            // Get image as a stream from the resources
            // Picture is defined as EmbeddedResource and DoNotCopy
            Stream resourceStream = currentAssembly.GetManifestResourceStream(
                "ArcGISRuntime.Resources.PictureMarkerSymbols.pin_star_blue.png");

            // Create new symbol using asynchronous factory method from stream
            PictureMarkerSymbol 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");
            }
        }
    }
}
XAML
<UserControl x:Class="ArcGISRuntime.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 Text="Enter an address to search or select from a preset option."
                           Grid.Row="0" Grid.Column="0" Grid.ColumnSpan="2"
                           TextAlignment="Center"
                           FontWeight="SemiBold" />
                <ComboBox x:Name="SearchBox"
                          Grid.Row="1" Grid.Column="0"
                          Margin="0,5,5,0"
                          IsEnabled="False" IsEditable="True"
                          SelectionChanged="OnSuggestionChosen" />
                <Button x:Name="SearchButton"
                        Grid.Row="1" Grid.Column="1"
                        Margin="0,5,0,0"
                        Content="Search" IsEnabled="False"
                        Click="Button_Click" />
            </Grid>
        </Border>
    </Grid>
</UserControl>
See Also
Additional Examples
Hyperlink to ExampleDescription
FindAddressFind the location for an address.