Question

I am using this piece of code to read from file but have an error “Cannot create an instance of abstract class or interface “System.IO.TextReader””

using (FileStream fileStream = File.Open(fileName, FileMode.Open, FileAccess.Read))
       using(TextReader reader = new TextReader(fileStream))//error
       {
           ...       
       }

Answer 1

You cannot instantiate TextReader object directly, its an abstract class. Try using StreamReader or StringReader instead.

using (TextReader reader = new StreamReader(fileStream))
{

}

See details/usage of StreamReader on MSDN