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我正在为我的程序创建一个日志记录机制，我必须将数据记录到一个文件中，该文件的位置和名称由用户指定。

我正在使用流编写器进行日志记录，如下所示 -

 StreamWriter writer = Writer ?? File.AppendText(FileName);

                writer.WriteLine(DateTime.Now + " " + text);
                writer.Flush();
                writer.Close();

但是，如果用户在我的程序运行时打开文件，则在用户关闭并重新打开文件之前，用户看不到新记录的行，他们有什么办法可以克服这种行为并且用户也能够看到新记录的行文件打开时。

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1 回答 1

1

使用 FindWindow 和 sendmessage 找到了一个解决方案，下面是相同的代码 -

 [DllImport("user32.dll", EntryPoint = "FindWindow")]
        private static extern IntPtr FindWindow(string lp1, string lp2);
        [DllImport("User32.dll", CharSet = CharSet.Auto)]
        extern static IntPtr FindWindowEx(IntPtr hwndParent, IntPtr hwndChildAfter, [In] string lpClassName, [In] string lpWindowName);

        [DllImport("User32.dll", EntryPoint = "SendMessage")]
        extern static int SendMessageGetTextLength(IntPtr hWnd, int msg, IntPtr wParam, IntPtr lParam);

        [DllImport("User32.dll")]
        public static extern int SendMessage(IntPtr hWnd, int uMsg, int wParam, string lParam);

        [DllImport("User32.dll")]
        public static extern int SendMessage(IntPtr hWnd, int uMsg, int wParam, int lParam);

  // Writes text line into log file. 
        // If the log file is opened with notepad, it is pasted there instead
        static public void Log(string inputText, DateTime startTime = new DateTime())
        {

            try 
            {

           /*     DateTime now = DateTime.Now;
                inputText = now.ToString() + " " + inputText;
                if (startTime != new DateTime())
                {
                    double diffTime = (int)(now - startTime).TotalMilliseconds;
                    String t;
                    if (diffTime >= 10000)
                        t = ((int) diffTime / 10000).ToString() + " s";
                    else
                        t = ((int)diffTime).ToString() + " ms";

                    inputText += ", " + t;
                }
*/ //irrelevant to the answer

                // search for log file opened with notepad
                IntPtr editBox = GetNotepadWindow();
                if (editBox == IntPtr.Zero)
                {
                    // log file is not open => append line to file
                    try
                    {
                        var writer = new StreamWriter(LogFile, true);
                        writer.WriteLine(inputText);
                        writer.Flush();
                        writer.Close();
                    }
                    catch
                    {
                    }
                    return;
                }
                // paste line into notepad
                int length = SendMessageGetTextLength(editBox, WM_GETTEXTLENGTH, IntPtr.Zero, IntPtr.Zero);                 
                SendMessage(editBox, EM_SETSEL, length, length);    // search end of file position

                inputText += "\r\n";
                SendMessage(editBox, EM_REPLACESEL, 1, inputText);  // append new line
            }
            catch
            {
            }
        }

        static private IntPtr GetNotepadWindow()
        {
            string windowName = LogFile;
            if (string.IsNullOrEmpty(LogFile))
                windowName = "Untitled";

            int index = windowName.LastIndexOf('\\');
            if (index >= 0)
                windowName = windowName.Substring(index+1);

            IntPtr mainWindow = FindWindow("Notepad", windowName + " - Notepad");
            IntPtr editBox = IntPtr.Zero;

            if (mainWindow != IntPtr.Zero)
                editBox = FindWindowEx(mainWindow, new IntPtr(0), "Edit", null);

            return editBox;
        }
于 2013-09-02T02:44:18.987 回答