Question

I’m very new to C# so please have some extra patience. What I am looking to do is read all files in a folder, to find a specific line (which can occur more than once in the same file) and get that output to show onscreen.

If anyone could point me in the direction to which methods I need to use it would be great.
Thanks!

Answer 1

Start with

const string lineToFind = "blah-blah";
var fileNames = Directory.GetFiles(@"C:\path\here");
foreach (var fileName in fileNames)
{   
    int line = 1;     
    using (var reader = new StreamReader(fileName))
    {
         // read file line by line 
         string lineRead;
         while ((lineRead = reader.ReadLine()) != null)
         {
             if (lineRead == lineToFind)
             {
                 Console.WriteLine("File {0}, line: {1}", fileName, line);
             }
             line++;
         }
    }
}

As Nick pointed out below, you can make search parallel using Task Library, just replace ‘foreach’ with Parallel.Foreach(filesNames, file=> {..});

Directory.GetFiles: http://msdn.microsoft.com/en-us/library/07wt70x2

StreamReader: http://msdn.microsoft.com/en-us/library/f2ke0fzy.aspx