private void Form1_Load(object sender, EventArgs e)
        {
            if (System.Diagnostics.EventLog.SourceExists("EreEventLog"))//判斷日誌位置
            {
                System.Diagnostics.EventLog.DeleteEventSource("EreEventLog");
            }
            System.Diagnostics.EventLog.CreateEventSource("EreEventLog", "Application");
            eventLog2.Log = "Application";  //設置名稱
            eventLog2.Source = "EreEventLog";//設置資料來源名稱
            this.eventLog1.MachineName = ".";//設置讀取名稱
            eventLog2.Clear();
        }

        private void button1_Click(object sender, EventArgs e)
        {
            if (eventLog1.Entries.Count > 0)//當日誌中有內容時
            {
                foreach (System.Diagnostics.EventLogEntry item in eventLog1.Entries)
                {
                    if (item.EntryType == System.Diagnostics.EventLogEntryType.Error)
                    {
                        listBox1.Items.Add(item.Message); //把資料讀入listBox
                        eventLog2.WriteEntry(item.Message, System.Diagnostics.EventLogEntryType.Error);
                    }
                }
            }
            else
                MessageBox.Show("沒有錯誤日誌");
        }

運用EventLog讀取系統日誌
把錯誤系統日誌寫入ListBox中,並把資料由系統中刪除