Gemini AI Integration with Blazor Smart Paste Button

16 Oct 202515 minutes to read

The Syncfusion Blazor SmartPaste Button component enables AI-powered, context-aware content pasting into forms, typically using OpenAI or Azure OpenAI. This guide explains how to integrate the Google Gemini AI service with the Smart Paste Button using the IChatInferenceService interface, enabling custom AI-driven responses in a Blazor Web App.

Setting Up Gemini

1. Obtain a Gemini API Key
   Visit Google AI Studio, sign in, and generate an API key.
2. Review Model Specifications
   Refer to Gemini Models Documentation for details on available models.

Create a Gemini AI Service

Create a service class to manage interactions with the Gemini API, including authentication, request/response handling, and safety settings for the Smart Paste Button.

1. Create a Services folder in your project.
2. Add a new file named GeminiService.cs in the Services folder.
3. Implement the service as shown below, storing the API key securely in a configuration file or environment variable (e.g., appsettings.json).

GeminiService.cs

using System.Net;
using System.Text;
using System.Text.Json;
using Microsoft.Extensions.AI;

public class GeminiService
{
    private readonly string _apiKey;
    private readonly string _modelName = "gemini-1.5-flash"; // Example model
    private readonly string _endpoint = "https://generativelanguage.googleapis.com/v1beta/models/";
    private static readonly HttpClient HttpClient = new(new SocketsHttpHandler
    {
        PooledConnectionLifetime = TimeSpan.FromMinutes(30),
        EnableMultipleHttp2Connections = true
    })
    {
        DefaultRequestVersion = HttpVersion.Version20 // Fallback to HTTP/2 for compatibility
    };
    private static readonly JsonSerializerOptions JsonOptions = new()
    {
        PropertyNamingPolicy = JsonNamingPolicy.CamelCase
    };

    public GeminiService(IConfiguration configuration)
    {
        _apiKey = configuration["Gemini:ApiKey"] ?? throw new ArgumentNullException("Gemini API key is missing.");
        HttpClient.DefaultRequestHeaders.Clear();
        HttpClient.DefaultRequestHeaders.Add("x-goog-api-key", _apiKey);
    }

    public async Task<string> CompleteAsync(IList<ChatMessage> chatMessages)
    {
        var requestUri = $"{_endpoint}{_modelName}:generateContent";
        var parameters = BuildGeminiChatParameters(chatMessages);
        var payload = new StringContent(
            JsonSerializer.Serialize(parameters, JsonOptions),
            Encoding.UTF8,
            "application/json"
        );

        try
        {
            using var response = await HttpClient.PostAsync(requestUri, payload);
            response.EnsureSuccessStatusCode();
            var json = await response.Content.ReadAsStringAsync();
            var result = JsonSerializer.Deserialize<GeminiResponseObject>(json, JsonOptions);
            return result?.Candidates?.FirstOrDefault()?.Content?.Parts?.FirstOrDefault()?.Text
                ?? "No response from model.";
        }
        catch (Exception ex) when (ex is HttpRequestException or JsonException)
        {
            throw new InvalidOperationException("Gemini API error.", ex);
        }
    }

    private GeminiChatParameters BuildGeminiChatParameters(IList<ChatMessage> messages)
    {
        var contents = messages.Select(m => new ResponseContent(
            m.Text,
            m.Role == ChatRole.User ? "user" : "model"
        )).ToList();

        return new GeminiChatParameters
        {
            Contents = contents,
            GenerationConfig = new GenerationConfig
            {
                MaxOutputTokens = 2000,
                StopSequences = new List<string> { "END_INSERTION", "NEED_INFO", "END_RESPONSE" } // Configurable stop sequences
            },
            SafetySettings = new List<SafetySetting>
            {
                new() { Category = "HARM_CATEGORY_HARASSMENT", Threshold = "BLOCK_ONLY_HIGH" },
                new() { Category = "HARM_CATEGORY_HATE_SPEECH", Threshold = "BLOCK_ONLY_HIGH" },
                new() { Category = "HARM_CATEGORY_SEXUALLY_EXPLICIT", Threshold = "BLOCK_ONLY_HIGH" },
                new() { Category = "HARM_CATEGORY_DANGEROUS_CONTENT", Threshold = "BLOCK_ONLY_HIGH" }
            }
        };
    }
}

NOTE

Store the Gemini API key in appsettings.json (e.g., { "Gemini": { "ApiKey": "your-api-key" } }) or as an environment variable to ensure security. The SafetySettings filter harmful content; adjust thresholds based on your application’s needs.

Define Request and Response Models

Define C# classes to match the Gemini API’s JSON request and response format.

1. Create a new file named GeminiModels.cs in the Services folder.
2. Add the following model classes:

GeminiModels.cs

public class Part
{
    public string Text { get; set; }
}

public class Content
{
    public Part[] Parts { get; init; } = Array.Empty<Part>();
}

public class Candidate
{
    public Content Content { get; init; } = new();
}

public class GeminiResponseObject
{
    public Candidate[] Candidates { get; init; } = Array.Empty<Candidate>();
}

public class ResponseContent
{
    public List<Part> Parts { get; init; }
    public string Role { get; init; }

    public ResponseContent(string text, string role)
    {
        Parts = new List<Part> { new Part { Text = text } };
        Role = role;
    }
}

public class GenerationConfig
{
    public int Temperature { get; init; } = 0;
    public int TopK { get; init; } = 0;
    public int TopP { get; init; } = 0;
    public int MaxOutputTokens { get; init; } = 2048;
    public List<string> StopSequences { get; init; } = new();
}

public class SafetySetting
{
    public string Category { get; init; } = string.Empty;
    public string Threshold { get; init; } = string.Empty;
}

public class GeminiChatParameters
{
    public List<ResponseContent> Contents { get; init; } = new();
    public GenerationConfig GenerationConfig { get; init; } = new();
    public List<SafetySetting> SafetySettings { get; init; } = new();
}

Create a Custom AI Service

Implement the IChatInferenceService interface to connect the Smart Paste Button to the Gemini service, acting as a bridge for AI-generated responses.

1. Create a new file named GeminiInferenceService.cs in the Services folder.
2. Add the following implementation:

GeminiInferenceService.cs

using Syncfusion.Blazor.AI;
using System.Threading.Tasks;

public class GeminiInferenceService : IChatInferenceService
{
    private readonly GeminiService _geminiService;

    public GeminiInferenceService(GeminiService geminiService)
    {
        _geminiService = geminiService;
    }

    public async Task<string> GenerateResponseAsync(ChatParameters options)
    {
        return await _geminiService.CompleteAsync(options.Messages);
    }
}

Configure the Blazor App

Register the Gemini service and IChatInferenceService implementation in the dependency injection container.

Update the ~/Program.cs file as follows:

~/Program.cs

using Microsoft.AspNetCore.Components;
using Microsoft.AspNetCore.Components.Web;
using Syncfusion.Blazor;
using Syncfusion.Blazor.AI;

var builder = WebApplication.CreateBuilder(args);

builder.Services.AddRazorPages();
builder.Services.AddServerSideBlazor();
builder.Services.AddSyncfusionBlazor();
builder.Services.AddSyncfusionSmartComponents();
builder.Services.AddSingleton<GeminiService>();
builder.Services.AddSingleton<IChatInferenceService, GeminiInferenceService>();

var app = builder.Build();
// ...

Add the Smart Paste Button

Add the Smart Paste Button to a form in the ~/Pages/Home.razor file to test the Groq AI integration.

~/Pages/Home.razor

@using Syncfusion.Blazor.DataForm
@using Syncfusion.Blazor.SmartComponents
@using System.ComponentModel.DataAnnotations

<SfDataForm ID="MyForm" Model="@EventRegistrationModel">
    <FormValidator>
        <DataAnnotationsValidator></DataAnnotationsValidator>
    </FormValidator>
    <FormItems>
        <FormItem Field="@nameof(EventRegistration.Name)" ID="firstname"></FormItem>
        <FormItem Field="@nameof(EventRegistration.Email)" ID="email"></FormItem>
        <FormItem Field="@nameof(EventRegistration.Phone)" ID="phonenumber"></FormItem>
        <FormItem Field="@nameof(EventRegistration.Address)" ID="address"></FormItem>
    </FormItems>
    <FormButtons>
        <SfSmartPasteButton IsPrimary="true" Content="Smart Paste" IconCss="e-icons e-paste"></SfSmartPasteButton>
    </FormButtons>
</SfDataForm>

<br>
<h4 style="text-align:center;">Sample Content</h4>
<div>
    Hi, my name is Jane Smith. You can reach me at [e-mail] or call me at [phone]. I live at 789 Pine Avenue, Suite 12, Los Angeles, CA 90001.
</div>

@code {
    private EventRegistration EventRegistrationModel = new();

    public class EventRegistration
    {
        [Required(ErrorMessage = "Please enter your name.")]
        [Display(Name = "Name")]
        public string Name { get; set; }

        [Required(ErrorMessage = "Please enter your email address.")]
        [Display(Name = "Email ID")]
        public string Email { get; set; }

        [Required(ErrorMessage = "Please enter your mobile number.")]
        [Display(Name = "Phone Number")]
        public string Phone { get; set; }

        [Required(ErrorMessage = "Please enter your address.")]
        [Display(Name = "Address")]
        public string Address { get; set; }
    }
}

NOTE

Ensure the Syncfusion Blazor DataForm package is installed for form integration.

Testing the Integration

1. Configure the Blazor Web App with the Groq AI service and Smart Paste Button as described above.
2. Add the code to ~/Pages/Home.razor, Program.cs, and the Services folder.
3. Run the application using Ctrl+F5 (Windows) or ⌘+F5 (macOS).
4. Copy the sample content provided in the Razor file.
5. Click the Smart Paste button to verify that the form fields are populated correctly using the Groq AI service.

NOTE

View Sample in GitHub.

Troubleshooting

If the Gemini AI integration does not work, try the following:

• No Suggestions Displayed: Verify that the Gemini API key and model name are correct in the configuration. Check the GeminiService implementation for errors.
• HTTP Request Failures: Ensure a stable internet connection and that the Gemini API endpoint (https://generativelanguage.googleapis.com/v1beta/models/) is accessible. Test with HTTP/2 if compatibility issues arise.
• Service Registration Errors: Confirm that GeminiService and GeminiInferenceService are registered in Program.cs.

See Also

• Getting Started with Syncfusion Blazor Smart Paste Button in Blazor Web App
• Customizing Smart Paste Button Suggestions