WebClient.UploadStringAsync Method (Uri, String, String, Object)
Uploads the specified string to the specified resource. This method does not block the calling thread.
Assembly: System (in System.dll)
[<HostProtectionAttribute(SecurityAction.LinkDemand, ExternalThreading = true)>] member UploadStringAsync : address:Uri * method:string * data:string * userToken:Object -> unit
- Type: System.Uri
The URI of the resource to receive the string. For HTTP resources, this URI must identify a resource that can accept a request sent with the POST method, such as a script or ASP page.
- Type: System.String
The HTTP method used to send the file to the resource. If null, the default is POST for http and STOR for ftp.
- Type: System.String
The string to be uploaded.
- Type: System.Object
A user-defined object that is passed to the method invoked when the asynchronous operation completes.
The address parameter is a null reference (Nothing in Visual Basic).
The data parameter is a null reference (Nothing in Visual Basic).
The URI formed by combining BaseAddress and address is invalid.
method cannot be used to send content.
There was no response from the server hosting the resource.
This method sends a string to a resource. The string is sent asynchronously using thread resources that are automatically allocated from the thread pool. Before uploading the string, this method converts it to a Byte array using the encoding specified in the Encoding property. To receive notification when the string upload completes, you can add an event handler to the UploadStringCompleted event.
This method does not block the calling thread while the string is being sent. To send a string and block while waiting for the server's response, use one of the UploadString methods.
Asynchronous operations that have not completed can be canceled using the CancelAsync method.
If the BaseAddress property is not an empty string ("") and address does not contain an absolute URI, address must be a relative URI that is combined with BaseAddress to form the absolute URI of the requested data. If the QueryString property is not an empty string, it is appended to address.
This member outputs trace information when you enable network tracing in your application. For more information, see Network Tracing in the .NET Framework.
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.