(精华)2020年8月18日 ASP.NET Core Log4数据库日志扩展

public class CustomEFLogger : ILogger
    {
        private string _CategoryName = null;
        public CustomEFLogger(string categoryName)
        {
            this._CategoryName = categoryName;
        }

        public IDisposable BeginScope<TState>(TState state)
        {
            return null;
        }

        public bool IsEnabled(LogLevel logLevel)
        {
            return true;
        }

        public void Log<TState>(LogLevel logLevel, EventId eventId, TState state, Exception exception, Func<TState, Exception, string> formatter)
        {
            System.Diagnostics.Debug.WriteLine($"************************************************************");
            System.Diagnostics.Debug.WriteLine($"CustomEFLogger {_CategoryName} {logLevel} {eventId} {state} start");

            System.Diagnostics.Debug.WriteLine($"异常信息：{exception?.Message}");
            System.Diagnostics.Debug.WriteLine($"信息：{formatter.Invoke(state, exception)}");

            System.Diagnostics.Debug.WriteLine($"CustomEFLogger {_CategoryName} {logLevel} {eventId} {state} end");
            System.Diagnostics.Debug.WriteLine($"************************************************************");
        }
    }

 public class CustomEFLoggerFactory : ILoggerFactory
    {
        public void AddProvider(ILoggerProvider provider)
        {
            
        }

        public ILogger CreateLogger(string categoryName)
        {
            return new CustomEFLogger(categoryName);
        }

        public void Dispose()
        {
           
        }
    }

/// <summary>
/// 日志问题
/// </summary>
public partial class JDDbContext : DbContext
{
    public JDDbContext(DbContextOptions<JDDbContext> options) : base(options)
    {
        Console.WriteLine("This is JDDbContext DbContextOptions");
    }

    private IConfiguration _IConfiguration = null;
    private ILoggerFactory _iLoggerFactory = null;
    public JDDbContext(IConfiguration configuration, ILoggerFactory loggerFactory)
    {
        this._IConfiguration = configuration;
        this._iLoggerFactory = loggerFactory;
        Console.WriteLine("This is JDDbContext configuration loggerFactory");
    }

    protected override void OnConfiguring(DbContextOptionsBuilder optionsBuilder)
    {
        var builder = new ConfigurationBuilder()
       .SetBasePath(Directory.GetCurrentDirectory())
       .AddJsonFile("appsettings.json");
        var configuration = builder.Build();
        var conn = configuration.GetConnectionString("JDDbConnection");
        optionsBuilder.UseSqlServer(conn);

        
        optionsBuilder.UseLoggerFactory(new CustomEFLoggerFactory());

        optionsBuilder.UseLoggerFactory(this._iLoggerFactory);

        optionsBuilder.UseSqlServer(this._IConfiguration.GetConnectionString("JDDbConnection"));

        optionsBuilder.UseSqlServer(StaticConstraint.JDDbConnection);

        optionsBuilder.UseSqlServer("Server=.;Database=advanced11;User id=sa;password=Passw0rd");

    }
 }