> For the complete documentation index, see [llms.txt](https://developer.harness.io/llms.txt). Markdown versions of documentation pages are available by appending `.md` to page URLs; this page is available as [Markdown](https://developer.harness.io/feature-management-experimentation/new-to-fme/sdks-and-customer-deployed-components/examples/dotnet-core-app.md).

# Create a .NET Core VB app using the FME SDK

### Overview <a href="#overview" id="overview"></a>

This example demonstrates how to build a basic .NET Core Visual Basic (VB) application that integrates with the FME SDK version 6.0.1. You will learn how to configure the SDK, enable debug logging with NLog, and evaluate feature flags for your users.

This setup is ideal for developers working with .NET Core and VB who want to incorporate feature flagging and experimentation into their applications.

### Environment <a href="#environment" id="environment"></a>

* Visual Studio for Mac 8.4
* NuGet 5.3
* .NET Core SDK 2.1.301

#### Packages <a href="#packages" id="packages"></a>

* Common.Logging.NLog41 3.4.1
* NLog.Config 4.6.8
* NLog 4.6.8
* NLog.Schema 4.6.8

### How to Use <a href="#how-to-use" id="how-to-use"></a>

#### 1. Configure Logging <a href="#id-1-configure-logging" id="id-1-configure-logging"></a>

The example uses NLog to enable detailed debug logging of the SDK operations. Logging is configured to write to a rolling file named `splitio.log`.

#### 2. Initialize the SDK <a href="#id-2-initialize-the-sdk" id="id-2-initialize-the-sdk"></a>

Update your FME API key, user ID, and feature flag names in the code below to match your environment.

#### 3. Sample Code <a href="#id-3-sample-code" id="id-3-sample-code"></a>

````
```vbnet
Imports System
Imports Splitio.Services.Client.Classes
Imports Common.Logging.Configuration
Imports NLog
Imports NLog.Config
Imports NLog.Targets

Public Class Application
Public Shared Sub Main() 

    ' Enable debug Logging
    Dim fileTarget = New FileTarget With {
    .Name = "splitio",
    .FileName = "splitio.log",
    .ArchiveFileName = "splitio.{#}.log",
    .LineEnding = LineEndingMode.CRLF,
    .Layout = "${longdate} ${level:uppercase=true} ${logger} - ${message} - ${exception:format=tostring}",
    .ConcurrentWrites = True,
    .CreateDirs = True,
    .ArchiveNumbering = ArchiveNumberingMode.DateAndSequence,
    .ArchiveAboveSize = 200000000,
    .ArchiveDateFormat = "yyyyMMdd",
    .MaxArchiveFiles = 30
    }
    Dim rule = New LoggingRule("*", LogLevel.Debug, fileTarget)
    Dim config = New LoggingConfiguration()
    config.AddTarget("splitio", fileTarget)
    config.LoggingRules.Add(rule)
    LogManager.Configuration = config
    Dim properties As NameValueCollection = New NameValueCollection()
    properties("configType") = "INLINE"
    Common.Logging.LogManager.Adapter = New Common.Logging.NLog.NLogLoggerFactoryAdapter(properties)

    ' Using the FME SDK
    Dim splitConfig As ConfigurationOptions
    splitConfig = New ConfigurationOptions()
    Dim factory As SplitFactory
    factory = New SplitFactory("API Key", splitConfig)
    Dim client As SplitClient
    client = factory.Client()
    client.BlockUntilReady(10000)
    System.Console.WriteLine("SDK is Ready")

    Dim treatment As String
    treatment = client.GetTreatment("User ID key","Feature flag name")
    System.Console.WriteLine(treatment)
End Sub
End Class
```
````

* Replace `"API Key"`, `"User ID key"`, and `"Feature flag name"` with your actual FME API key, user identifiers, and feature flag names.
* Build and run your .NET Core VB app to start evaluating feature flags.
* Check the generated `splitio.log` file for debug logs.