Was this page helpful?
Your feedback about this content is important. Let us know what you think.
Additional feedback?
1500 characters remaining
ReadLineAsync Method

StringReader.ReadLineAsync Method

.NET Framework 4.6 and 4.5

Reads a line of characters asynchronously from the current string and returns the data as a string.

Namespace:  System.IO
Assemblies:   mscorlib (in mscorlib.dll)
  System.IO (in System.IO.dll)

[ComVisibleAttribute(false)]
public override Task<string> ReadLineAsync()

Return Value

Type: System.Threading.Tasks.Task<String>
A task that represents the asynchronous read operation. The value of the TResult parameter contains the next line from the string reader, or is null if all the characters have been read.

ExceptionCondition
ArgumentOutOfRangeException

The number of characters in the next line is larger than MaxValue.

ObjectDisposedException

The string reader has been disposed.

InvalidOperationException

The reader is currently in use by a previous read operation.

The following example shows how to read one line at a time from a string asynchronously.

using System;
using System.IO;
using System.Text;

namespace ConsoleApplication
{
    class Program
    {
        static void Main(string[] args)
        {
            ReadCharacters();
        }

        static async void ReadCharacters()
        {
            StringBuilder stringToRead = new StringBuilder();
            stringToRead.AppendLine("Characters in 1st line to read");
            stringToRead.AppendLine("and 2nd line");
            stringToRead.AppendLine("and the end");

            string readText;

            using (StringReader reader = new StringReader(stringToRead.ToString()))
            {
                while ((readText = await reader.ReadLineAsync()) != null)
                {
                    Console.WriteLine(readText);
                }
            }
        }
    }
}
// The example displays the following output: 
// 
// Characters in 1st line to read 
// and 2nd line 
// and the end 
//

.NET Framework

Supported in: 4.6, 4.5

.NET for Windows Phone apps

Supported in: Windows Phone 8.1, Windows Phone Silverlight 8.1, Windows Phone Silverlight 8
Show:
© 2015 Microsoft