在大文件中搜索和替换正则表达式而不会出现OutOfMemoryException

I created a little code which searches for a Regex string and replaces that with something else, it then creates a new output file with the changes made. The code seems to work well with smaller files, but for 100 MB or larger files I am giving the System.OutOfMemoryException' error. I created a little code which searches for a Re