## Table of Contents

1. [Introduction](#introduction)
2. [Install NLog via NuGet](#install-nlog-via-nuget)
3. [Add NLog.config File](#add-nlogconfig-file)
4. [Using NLog in Code](#using-nlog-in-code)
5. [Conclusion](#conclusion)

## Introduction

This blog shows an example of how to configure NLog to log to a file, a database, and call a class.

Example requirements for logging:

  - Debug, Info, Warning, Error, and Fatal level logs to a file
  - Info, Warning, Error, and Fatal logs to a database
  - Fatal logs send an email

## Install NLog via NuGet

Type the following in the Visual Studio Package Manager Console window:
`Install-Package NLog`

## Add NLog.config File

```
<?xml version="1.0" encoding="utf-8" ?>


  






        Data Source=databaseservername;Initial Catalog=databasename;User Id=username;Password=password;


        insert into YourTableForLogging(date,level,message,machine_name, user_name, call_site,thread, exception, stacktrace) values(@time_stamp, @level, @message,@machinename, @user_name, @call_site, @threadid, @log_exception, @stacktrace);

      






```

## Using NLog in Code

At this point, the NLog configuration is ready, and you should be able to use NLog in your code.

For how to call NLog, you can reference the following article to write code in .NET. NLog will automatically handle the logging, and if you log at the Fatal level, it will call the specified class to perform the action.

How to call NLog

## Conclusion

NLog is a flexible logging framework for .NET that supports multiple targets including files, databases, and email. By configuring the NLog.config file, you can easily route different log levels to different destinations.

This blog shows an example of how to configure NLog to log to a file, a database, and trigger a class call.

How to Configure NLog to Log to File, Database, and Send Email

## Table of Contents

1. [Introduction](#introduction)
2. [NLog Database Target Configuration](#nlog-database-target-configuration)
3. [Dynamically Change Connection String in Code](#dynamically-change-connection-string-in-code)
4. [Conclusion](#conclusion)

## Introduction

You can define log-to-database settings in NLog, but you can't change the connection string depending on your environment. This blog shows how to dynamically change the connection string in C# based on your environment.

## NLog Database Target Configuration

```
<?xml version="1.0" encoding="utf-8" ?>


  






        Data Source=databaseservername;Initial Catalog=databasename;User Id=username;Password=password;


        insert into YourTableForLogging(date,level,message,machine_name, user_name, call_site,thread, exception, stacktrace) values(@time_stamp, @level, @message,@machinename, @user_name, @call_site, @threadid, @log_exception, @stacktrace);





















    






```

## Dynamically Change Connection String in Code

The following code shows how to dynamically change the connection string defined in NLog:

```
using (var databaseTarget = (DatabaseTarget)LogManager.Configuration.FindTargetByName("database"))
                {
                    var entityFrameworkConnection = ConfigurationManager.ConnectionStrings["MyDatabaseName"].ConnectionString;
                    var builder = new EntityConnectionStringBuilder(entityFrameworkConnection);
                    var connectionString = builder.ProviderConnectionString;
                    databaseTarget.ConnectionString = connectionString;
                }
```

## Conclusion

By using `LogManager.Configuration.FindTargetByName` and `EntityConnectionStringBuilder`, you can dynamically override the NLog database target's connection string at runtime. This approach allows you to use different connection strings for different environments without modifying the NLog config file.

You can define log-to-database settings in NLog, but you can't change the connection string depending on your environment. This blog shows how to change the connection string in C# based on your environment.

NLog

How to Configure NLog to Log to File, Database, and Send Email

Override Connection String at NLog Config Setting