I have an ASP.Net application (actually Lightswitch is involved here, not sure that it matters much in this case).
I have the following code. It starts in the LogIn.aspx which calls RegisterUser on the OnLoggedIn event.
public static void RegisterUser(string userName)
{
using (var connection = new SqlConnection(IzendaSettings.ConnectionString))
using (var command = connection.CreateCommand())
{
connection.Open();
command.CommandText = @"SELECT CU.DisplayName, CU.ClientId, C.Name FROM ClientUser CU INNER JOIN Client C on C.ClientId = CU.ClientId WHERE CU.UserName = @userName AND Rights = 0";
command.Parameters.Add("userName", SqlDbType.NVarChar).Value = userName;
using (var reader = command.ExecuteReader())
{
if (reader.Read())
{
var unused = RegisterUserAsync(userName, reader.GetString(0), reader.GetInt32(1).ToString(), reader.GetString(0));
}
}
}
}
internal static async Task RegisterUserAsync(string userName, string fullName, string clientId, string clientName)
{
try
{
var token = TokenAuthorization.GetSystemAdministratorToken();
while (Bootstrap.Initalizing)
{
Thread.Yield();
}
var izenda = await TenantProcess.Initialize(clientId, clientName, token);
var connection = await izenda.SetUpConnection(IzendaSettings.ConnectionString);
await izenda.PutUserInRole("User", userName, fullName, "~/BI/tenantRolePermission.json", connection);
}
catch (Exception e)
{
Logger.Error("Register User", e);
}
}
The async code deadlocks. I'm trying to just run it off in a separate thread, I don't await it on purpose.
Changing the call to RegisterUserAsync to this (with the appropriate capture of the SQL prior to launching the thread):
Task.Run(() => RegisterUserAsync(userName, user.FullName, user.ClientId, user.ClientName));
Solves the problem. I understand why calling Task.Run solves an async call that you want to wait for without deadlocking, but I don't understand why in this case the deadlock was happening. (The Initializing variable was false - I logged a debug statement to make sure, so it never actually did the Thread.Yield, but I wouldn't see why that would affect it anyway).
Why was the deadlock happening in the old code?
