Why is Serilog logging in Main() but not in Form1 - serilog

Question

Using Serilog with the MSSQL sink. I am logging OK when I write to the log after defining it in Main(). When I try to write to the log in Form1 form loading event handler it does not log.
The code in Program.cs Main() look like this and works.
var connectionString = #"Data Source=XXX\XXX; Initial Catalog=XXX; User ID=XXX; Password=XXX;";
var sinkOpts = new MSSqlServerSinkOptions();
sinkOpts.TableName = "Logs";
var columnOption = new ColumnOptions();
columnOption.Store.Remove(StandardColumn.MessageTemplate);
Log.Logger = new LoggerConfiguration()
.WriteTo.MSSqlServer(
connectionString: connectionString,
sinkOptions: sinkOpts,
columnOptions: columnOption
).CreateLogger();
Log.Error("nujcsin");
Log.CloseAndFlush();
Code in Form1 loading handler looks like this. It does not log:
private void Form1_Load(object sender, EventArgs e)
{
List<ToolLocationItem> toolList = new List<ToolLocationItem>();
fastObjectListView1.ClearObjects();
fastObjectListView1.Refresh();
FillList();
Log.Information("Testing in Form1");
Log.CloseAndFlush();
}
I have tried replacing "WriteTo" with "AuditTo". I get nothing but my log entry in Main(). My Log.Information is not throwing any errors.
Why is Serilog not logging in Form1?
Edit
Same behaviour when using the file sink. Serilog logs when the logging statement is in the Main procedure but not elsewhere. It seems to be something that Serilog doesn't like rather than the sink.

Answer 1

You have Log.CloseAndFlush() in the code shortly after you initialize your logger. Like the documentation points out, this should be called only once right before the application exits.
Log.CloseAndFlush() will give the sinks a chance to wrap up what they were logging (some sinks are asynchronous) and then kill the logger, so any events logged after that will be lost. It disposes of the logger. So if you call that too soon, you're killing logging in the rest of your app.
You might think that putting it in a variable and then assigning it to the static logger was the solution, but you're misunderstanding what's going on. You haven't shown exactly what you did, but let's say you did this...
var log = new LoggerConfiguration()
.WriteTo.MSSqlServer(
connectionString: connectionString,
sinkOptions: sinkOpts,
columnOptions: columnOption
).CreateLogger();
Log.CloseAndFlush();
Log.Logger = log;
Now you've created a logger, assigned it to a local variable, closed and flushed (destroy/disposed) of the original static logger (there's a default implementation there that does nothing) then assigned the logger from your local variable to be the static logger. The key point is that all of this wouldn't be necessary if you closed and flushed in the proper place in the code, which is right before the program exits.

Answer 2

Wow. A new day and a fresh look.
What I did wrong is the following:
I needed to define the logger like this:
var log = new LoggerConfiguration()
.WriteTo.MSSqlServer(
connectionString: connectionString,
sinkOptions: sinkOpts,
columnOptions: columnOption
).CreateLogger();
and then:
Log.Logger = log;
If I defined my logger like this it did not seem to work outside the Main().
Log.Logger = new LoggerConfiguration()
.WriteTo.MSSqlServer(
connectionString: connectionString,
sinkOptions: sinkOpts,
columnOptions: columnOption
).CreateLogger();