C# 在c中写入文本文件时发生IoException#

我有一个文本文件，我需要根据正则表达式匹配更新它，但是当我的程序试图在文本文件中写入一行时，它给出了以下错误

The process cannot access the file 'D:\Archieve\20140123.text' because it is being used by another process.

这是我的密码

哪里出错了？

使用

File.Create（textfilename.Close（）

正如错误消息所示，创建文件不需要单独的指令。
StreamWriter将处理它：下面是您所使用的构造函数的描述

> Initializes a new instance of the StreamWriter class for the specified
> file by using the default encoding and buffer size. If the file
> exists, it can be either overwritten or appended to. If the file does
> not exist, this constructor creates a new file.

TextWriter tsw = new StreamWriter(textfilename,true);

> Initializes a new instance of the StreamWriter class for the specified
> file by using the default encoding and buffer size. If the file
> exists, it can be either overwritten or appended to. If the file does
> not exist, this constructor creates a new file.