在文本文件中搜索

string path = @"c:\somedir";

string searchtext = "something";

DirectoryInfo di = new DirectoryInfo(path);

FileInfo[] files = di.GetFiles("*.txt");

foreach (FileInfo file in files)

{

    using (StreamReader sr = new StreamReader(file.FullName))

    {

        string content = sr.ReadToEnd().ToLower();

        if(content.Contains(searchtext.ToLower()))

            Console.WriteLine("{0} contains \"{1}\"",file.Name,searchtext);

        else

            Console.WriteLine("{0} does not contain \"{1}\"", file.Name, searchtext);

    }

}