Azure SDK for .NET Samples

Scenario: Tracking a Button Click

Imagine a web application where users can submit a form. We want to track when the submit button is clicked as a custom event.

Prerequisites

• An Azure subscription.
• An Azure Application Insights resource configured for your application.
• .NET SDK installed.

C# Code Sample

First, ensure you have the necessary NuGet package installed:

dotnet add package Microsoft.ApplicationInsights

Here's the C# code to send a custom event:

using Microsoft.ApplicationInsights;
using Microsoft.ApplicationInsights.Extensibility;
using System;

public class ApplicationInsightsService
{
    private readonly TelemetryClient _telemetryClient;

    public ApplicationInsightsService(string instrumentationKey)
    {
        if (string.IsNullOrEmpty(instrumentationKey))
        {
            throw new ArgumentNullException(nameof(instrumentationKey));
        }
        // Configure the instrumentation key
        TelemetryConfiguration.Active.InstrumentationKey = instrumentationKey;
        _telemetryClient = new TelemetryClient();
    }

    public void TrackSubmitButtonClick()
    {
        // Track a custom event
        _telemetryClient.TrackEvent("SubmitButtonClick");

        // You can also add properties to the event for more context
        _telemetryClient.TrackEvent("SubmitButtonClick", new Dictionary<string, string>
        {
            { "ButtonLocation", "UserProfileForm" },
            { "ClickedByUserRole", "Admin" }
        });

        // It's a good practice to flush pending telemetry to ensure it's sent
        _telemetryClient.Flush();
        Console.WriteLine("Custom event 'SubmitButtonClick' tracked.");
    }

    // Example of tracking a more complex event
    public void TrackDataProcessingComplete(string dataType, int processedItems)
    {
        _telemetryClient.TrackEvent("DataProcessingComplete", new Dictionary<string, string>
        {
            { "DataType", dataType }
        },
        new Dictionary<string, double>
        {
            { "ItemsProcessed", processedItems }
        });

        Console.WriteLine($"Custom event 'DataProcessingComplete' tracked for {processedItems} {dataType} items.");
    }
}

// Example Usage:
public class Program
{
    public static void Main(string[] args)
    {
        string instrumentationKey = Environment.GetEnvironmentVariable("APPLICATIONINSIGHTS_INSTRUMENTATIONKEY");
        if (string.IsNullOrEmpty(instrumentationKey))
        {
            Console.WriteLine("Please set the APPLICATIONINSIGHTS_INSTRUMENTATIONKEY environment variable.");
            return;
        }

        var appInsightsService = new ApplicationInsightsService(instrumentationKey);

        // Simulate a button click
        appInsightsService.TrackSubmitButtonClick();

        // Simulate data processing completion
        appInsightsService.TrackDataProcessingComplete("CustomerRecords", 150);
    }
}
                

Explanation

1. TelemetryClient: This is the core class for sending telemetry data to Application Insights.

2. Instrumentation Key: You need to provide your Application Insights resource's instrumentation key. It's best practice to load this from configuration or environment variables.

3. TrackEvent(): This method is used to send custom events.

• The first parameter is the event name (e.g., "SubmitButtonClick").
• Optional parameters allow you to add custom properties (string key-value pairs) and metrics (double key-value pairs) for richer analysis.

4. Flush(): Ensures that any telemetry still in the buffer is sent immediately. This is particularly important in short-lived console applications.