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StringWriter.WriteAsync Method (Char[], Int32, Int32)

.NET Framework 4.6 and 4.5

Writes a subarray of characters to the string asynchronously.

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

[ComVisibleAttribute(false)]
[HostProtectionAttribute(SecurityAction.LinkDemand, ExternalThreading = true)]
public override Task WriteAsync(
	char[] buffer,
	int index,
	int count
)

Parameters

buffer
Type: System.Char[]

The character array to write data from.

index
Type: System.Int32

The position in the buffer at which to start reading data.

count
Type: System.Int32

The maximum number of characters to write.

Return Value

Type: System.Threading.Tasks.Task
A task that represents the asynchronous write operation.

ExceptionCondition
ArgumentNullException

buffer is null.

ArgumentException

The index plus count is greater than the buffer length.

ArgumentOutOfRangeException

index or count is negative.

ObjectDisposedException

The string writer is disposed.

InvalidOperationException

The string writer is currently in use by a previous write operation.

NoteNote

The HostProtectionAttribute attribute applied to this type or member has the following Resources property value: ExternalThreading. The HostProtectionAttribute does not affect desktop applications (which are typically started by double-clicking an icon, typing a command, or entering a URL in a browser). For more information, see the HostProtectionAttribute class or SQL Server Programming and Host Protection Attributes.

The following example shows how to write characters by using the WriteAsync(Char[], Int32, Int32) method.

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

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

        static async void WriteCharacters()
        {
            StringBuilder stringToWrite = new StringBuilder("Characters in StringBuilder");
            stringToWrite.AppendLine();

            using (StringWriter writer = new StringWriter(stringToWrite))
            {
                UnicodeEncoding ue = new UnicodeEncoding();
                char[] charsToAdd = ue.GetChars(ue.GetBytes("and chars to add"));

                await writer.WriteAsync(charsToAdd, 0, charsToAdd.Length);

                Console.WriteLine(stringToWrite.ToString());
            }
        }
    }
}
// The example displays the following output: 
// 
// Characters in StringBuilder 
// and chars to add 
//

.NET Framework

Supported in: 4.6, 4.5

Supported in: Windows Phone 8.1

Supported in: Windows Phone Silverlight 8.1

Supported in: Windows Phone Silverlight 8
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