StringReader.ReadLineAsync Método

Definición

Lee de forma asincrónica una línea de caracteres de la cadena actual y devuelve los datos como una cadena.Reads a line of characters asynchronously from the current string and returns the data as a string.

public:
 override System::Threading::Tasks::Task<System::String ^> ^ ReadLineAsync();
[System.Runtime.InteropServices.ComVisible(false)]
public override System.Threading.Tasks.Task<string> ReadLineAsync ();
override this.ReadLineAsync : unit -> System.Threading.Tasks.Task<string>
Public Overrides Function ReadLineAsync () As Task(Of String)

Devoluciones

Tarea que representa la operación de lectura asincrónica.A task that represents the asynchronous read operation. El valor del parámetro TResult contiene la línea siguiente del lector de cadenas, o es null si se han leído todos los caracteres.The value of the TResult parameter contains the next line from the string reader, or is null if all the characters have been read.

Atributos

Excepciones

El número de caracteres de la siguiente línea es mayor que MaxValue.The number of characters in the next line is larger than MaxValue.

El lector de cadenas se ha desechado.The string reader has been disposed.

Una operación de lectura anterior está usando actualmente el lector.The reader is currently in use by a previous read operation.

Ejemplos

En el ejemplo siguiente se muestra cómo leer una línea a la vez desde una cadena de forma asincrónica.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
//
Imports System.IO
Imports System.Text

Module Module1

    Sub Main()
        ReadCharacters()
    End Sub

    Async Sub ReadCharacters()
        Dim stringToRead = New StringBuilder()
        stringToRead.AppendLine("Characters in 1st line to read")
        stringToRead.AppendLine("and 2nd line")
        stringToRead.AppendLine("and the end")

        Using reader As StringReader = New StringReader(stringToRead.ToString())
            Dim readText As String = Await reader.ReadLineAsync()
            While Not IsNothing(readText)
                Console.WriteLine(readText)
                readText = Await reader.ReadLineAsync()
            End While
        End Using
    End Sub
End Module
' The example displays the following output:
'
' Characters in 1st line to read
' and 2nd line
' and the end
'

Se aplica a