Xamarin.Forms: Bing Spell Check Using Cognitive Service

Introduction

In this post, you will learn how to detect and correct spelling mistakes in your app using Cognitive Service Bing Spell Check API in Xamarin.Forms.

Xamarin.Forms code runs on multiple platforms — each of which has its own filesystem. This means that reading and writing files is most easily done using the native file APIs on each platform. Alternatively, embedded resources are a simpler solution to distribute data files with an app.

Cognitive Services

Xamarin and Cognitive Services together can infuse your apps, websites, and bots with intelligent algorithms to see, hear, speak, understand, and interpret your user needs through natural methods of communication. Also, they help you transform your business with AI today.

Use AI to solve business problems:

• Vision
• Speech
• Knowledge
• Search
• Language

Bing Spell Check API

1. It helps users correct spelling errors, recognize the differences among names, brand names, and slang, as well as understand homophones as they are typing.
2. It has developed a web-based spell checker.
3. It returns a list of words it does recognize with suggested replacements.

Prerequisites

• Visual Studio 2017 or Later (Windows or Mac)
• Bing Spell Check API Key

Setting up a Xamarin.Forms Project

Start by creating a new Xamarin.Forms project. You’ll learn more by going through the steps yourself.

Visual Studio 2019 has more options in the opening window. Clone or check out the code from any repository or open a project or solution for your computer.

Click "Create a new project."

1. Now, filter by Project Type: Mobile

2. Choose the Mobile App (Xamarin. forms) project under C# and Mobile.

3. Name your app. You probably want your project and solution to use the same name as your app. Put it on your preferred location for projects and click "Create."

4. Now, select the blank app and target platforms — Android, iOS, and Windows (UWP).

5. Subsequently, go to the solution. In there, you get all the files and sources of your project (.NET Standard). Now, select XAML page and double-click to open the MainPage.Xaml page.

6. You now have a basic Xamarin.Forms app. Click the Play button to try it out.

Get Bing Spell Check API Key

In this step, get Bing Spell Check API Key. Go to the following link.

https://azure.microsoft.com/en-in/services/cognitive-services/

Click "Try Cognitive Services for free."

Now you can choose Bing Spell Check API under Language APIs. Afterward, click "Get API Key."

Now, the API key is activated. You can use it now.

Note: The trial key is only available for 7 days.

Setting up the User Interface

Go to MainPage.Xaml and write the following code.

MainPage.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:local="clr-namespace:XamarinCognitive"
             x:Class="XamarinCognitive.MainPage">

    <StackLayout>
        <StackLayout>
            <StackLayout HorizontalOptions="Center" VerticalOptions="Start">
                <Image x:Name="imgBanner" Source="banner.png" ></Image>
                <Image Margin="0,0,0,10" x:Name="imgCognitive" HeightRequest="100" Source="cognitiveservice.png" ></Image>
                <Label Margin="0,0,0,10" Text="Bing Spell Check" FontAttributes="Bold" FontSize="Large" TextColor="Gray" HorizontalTextAlignment="Center" ></Label>
                <Entry x:Name="txtSearch" Placeholder="Type here.."></Entry>
                <Button x:Name="btnCheck" WidthRequest="50" Text="Check" Clicked="BtnCheck_Clicked" />
                <StackLayout HorizontalOptions="CenterAndExpand" Margin="10,0,0,10">
                    <ListView x:Name="suggestionsList">

                    </ListView>
                </StackLayout>
            </StackLayout>
        </StackLayout>
    </StackLayout>

</ContentPage>

Click the play button to try it out.

NuGet Packages

Now, add the following NuGet Packages.

• Newtonsoft.Json

Add Newtonsoft.Json NuGet

Go to Solution Explorer and select your solution. Right-click and select "Manage NuGet Packages for Solution". Search "Newtonsoft.Json" and add Package. Remember to install it(.NET Standard).

Create a Model

In this step, you can create a model for Deserializing your response.

ResponseModel.cs

using System;  
using System.Collections.Generic;  
using System.Text;  

namespace XamarinCognitive
{
    public class ResponseModel
    {
        public string _type { get; set; }
        public List<FlaggedToken> flaggedTokens { get; set; }
    }
    public class Suggestion
    {
        public string suggestion { get; set; }
        public double score { get; set; }
    }

    public class FlaggedToken
    {
        public int offset { get; set; }
        public string token { get; set; }
        public string type { get; set; }
        public List<Suggestion> suggestions { get; set; }
    }


}

Bing Spell Check

In this step, write the following code for Bing Spell Check.

Note:

Try out the spell check capabilities with Bing Spell Search API v7.

• ‘Spell’ is more aggressive in order to return better search results,
• ‘Proof’ is less aggressive and adds capitalisation, basic punctuation and other features to aid document creation.

MainPage.xaml.cs

using Xamarin.Forms;
using Newtonsoft.Json;
using System.Net.Http;
using System.Net.Http.Headers;

namespace XamarinCognitive
{
    public partial class MainPage : ContentPage
    {
        static string host = "https://api.cognitive.microsoft.com";
        static string path = "/bing/v7.0/spellcheck?";
        static string params_ = "mkt=en-US&mode=proof";
        static string key = "cdf8476d88*******66b08e53";

        public MainPage()
        {
            InitializeComponent();
        }

        private async void BtnCheck_Clicked(object sender, EventArgs e)
        {
            List<string> listSuggestions = new List<string>();
            var responseString = await SpellCheck(txtSearch.Text);
            var result = JsonConvert.DeserializeObject<ResponseModel>(responseString);
            if(result.flaggedTokens.Count!=0)
            {
                foreach (var item in result.flaggedTokens[0].suggestions)
                {
                    listSuggestions.Add(item.suggestion);
                }
                suggestionsList.ItemsSource = null;
                suggestionsList.ItemsSource = listSuggestions;
            }

        }


        //Bing Spell Check
        public async static Task<string> SpellCheck(string text)
        {
            HttpClient client = new HttpClient();
            client.DefaultRequestHeaders.Add("Ocp-Apim-Subscription-Key", key);
            HttpResponseMessage response = new HttpResponseMessage();
            string uri = host + path + params_;

            List<KeyValuePair<string, string>> values = new List<KeyValuePair<string, string>>();
            values.Add(new KeyValuePair<string, string>("text", text));

            using (FormUrlEncodedContent content = new FormUrlEncodedContent(values))
            {
                content.Headers.ContentType = new MediaTypeHeaderValue("application/x-www-form-urlencoded");
                response = await client.PostAsync(uri, content);
            }

            string client_id;
            if (response.Headers.TryGetValues("X-MSEdge-ClientID", out IEnumerable<string> header_values))
            {
                client_id = header_values.First();
                Console.WriteLine("Client ID: " + client_id);
            }

            string contentString = await response.Content.ReadAsStringAsync();

            return contentString;
        }


    }
}

Click the Play button to try it out.

I hope you have understood how to detect and correct spelling mistakes in your app using Cognitive Service Bing Spell Check API in Xamarin.Forms.

More samples from GitHub.

Thanks for reading. Please share comments and feedback. Happy coding! :)