protected void btnLogin_Click(object sender, EventArgs e)
        {
            try { var i = 0; var a = 2 / i; }
            catch (Exception ex) { LoggingService.LogError("WebParts", ex.Message); }
        }

using System;
using System.Collections.Generic;
using System.Linq;
using System.Text;
using Microsoft.SharePoint.Administration; //需要引入

namespace CopyListContent
{
    public class LoggingService : SPDiagnosticsServiceBase
    {
        public static string MyDiagnosticAreaName = "MyDiagnosticTest";
        private static LoggingService _Current;
        public static LoggingService Current
        {
            get
            {
                if (_Current == null)
                { _Current = new LoggingService(); }
                return _Current;
            }
        }

private LoggingService()
            : base("MyDiagnosticTest Logging Service", SPFarm.Local)
        { }

protected override IEnumerable<SPDiagnosticsArea> ProvideAreas()
        {
            List<SPDiagnosticsArea> areas = new List<SPDiagnosticsArea>  {            
                new SPDiagnosticsArea(MyDiagnosticAreaName, new List<SPDiagnosticsCategory>
                {new SPDiagnosticsCategory("WebParts", TraceSeverity.Unexpected, EventSeverity.Error) })};
            return areas;
        }

public static void LogError(string categoryName, string errorMessage)
        {
            SPDiagnosticsCategory category = LoggingService.Current.Areas[MyDiagnosticAreaName].Categories[categoryName];
            LoggingService.Current.WriteTrace(0, category, TraceSeverity.Unexpected, errorMessage);
        }
    }

}

protected void btnLogin_Click(object sender, EventArgs e)
        {
            try { var i = 0; var a = 2 / i; }
            catch (Exception ex)
            { SPDiagnosticsService.Local.WriteTrace(0,
                new SPDiagnosticsCategory("My Category", TraceSeverity.Unexpected, EventSeverity.Error),
                TraceSeverity.Unexpected, ex.Message, ex.StackTrace);
            }
        }