How can search by streamreader line by line

int counter = 0;
string line;

// Read the file and display it line by line.
System.IO.StreamReader file =
   new System.IO.StreamReader("c:\\yourFile");
while((line = file.ReadLine()) != null)
{
   Console.WriteLine (line);
   counter++;
}

file.Close();
// Suspend the screen.
Console.ReadLine();