SmtpClient.SendAsync Method (String, String, String, String, Object)
Sends an e-mail message to an SMTP server for delivery. The message sender, recipients, subject, and message body are specified using String objects. This method does not block the calling thread and allows the caller to pass an object to the method that is invoked when the operation completes.
Assembly: System (in System.dll)
[HostProtectionAttribute(SecurityAction.LinkDemand, ExternalThreading = true)] public void SendAsync( string from, string recipients, string subject, string body, Object userToken )
- Type: System.Object
A user-defined object that is passed to the method invoked when the asynchronous operation completes.
from is null.
recipient is null.
from is Empty.
recipient is Empty.
Host is null.
Host is equal to the empty string ("").
Port is zero.
This object has been disposed.
The connection to the SMTP server failed.
The operation timed out.
The message could not be delivered to one or more of the recipients in recipients.
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.
To receive notification when the e-mail has been sent or the operation has been canceled, add an event handler to the SendCompleted event. You can cancel a SendAsync operation by calling the SendAsyncCancel method.
Before calling this method, the Host and Port properties must be set either through the configuration files or by setting the properties or passing this information into the SmtpClient(String, Int32) constructor.
If you receive an SmtpException exception, check the StatusCode property to find the reason the operation failed. The SmtpException can also contain an inner exception that indicates the reason the operation failed.
To send mail and block while it is transmitted to the SMTP server, use one of the Send methods.
Windows 7, Windows Vista, Windows XP SP2, Windows XP Media Center Edition, Windows XP Professional x64 Edition, Windows XP Starter Edition, Windows Server 2008 R2, Windows Server 2008, Windows Server 2003, Windows Server 2000 SP4, Windows Millennium Edition, Windows 98
The .NET Framework and .NET Compact Framework do not support all versions of every platform. For a list of the supported versions, see .NET Framework System Requirements.