WebClient.OpenRead Method

Definition

Namespace:

System.Net

Assembly:

System.Net.WebClient.dll

Opens a readable stream for the data downloaded from a resource with the specified URI.

Overloads

OpenRead(String)	Opens a readable stream for the data downloaded from a resource with the URI specified as a String.
OpenRead(Uri)	Opens a readable stream for the data downloaded from a resource with the URI specified as a Uri.

OpenRead(String)

Source:

WebClient.cs

Opens a readable stream for the data downloaded from a resource with the URI specified as a String.

public:
 System::IO::Stream ^ OpenRead(System::String ^ address);

public System.IO.Stream OpenRead (string address);

member this.OpenRead : string -> System.IO.Stream

Public Function OpenRead (address As String) As Stream

Parameters

address

String

The URI specified as a String from which to download data.

Returns

Stream

A Stream used to read data from a resource.

Exceptions

ArgumentNullException

The address parameter is null.

WebException

The URI formed by combining BaseAddress, address is invalid.

-or-

An error occurred while downloading data.

Examples

The following code example opens the resource identified by uriString and displays the results on the system console. The Stream returned by OpenRead is closed when the data has been read.

// Create a new WebClient instance.
WebClient^ myWebClient = gcnew WebClient;
// Download home page data.
Console::WriteLine( "Accessing {0} ...", uriString );
// Open a stream to point to the data stream coming from the Web resource.
Stream^ myStream = myWebClient->OpenRead( uriString );

Console::WriteLine( "\nDisplaying Data :\n" );
StreamReader^ sr = gcnew StreamReader( myStream );
Console::WriteLine( sr->ReadToEnd() );

// Close the stream.
myStream->Close();

// Create a new WebClient instance.
WebClient myWebClient = new WebClient();
// Download home page data. 
Console.WriteLine("Accessing {0} ...",  uriString);						
// Open a stream to point to the data stream coming from the Web resource.
Stream myStream = myWebClient.OpenRead(uriString);

Console.WriteLine("\nDisplaying Data :\n");
StreamReader sr = new StreamReader(myStream);
Console.WriteLine(sr.ReadToEnd());

// Close the stream. 
myStream.Close();

    ' Create a new WebClient instance.
    Dim myWebClient As New WebClient()

    ' Download home page data. 
    Console.WriteLine("Accessing {0} ...", uriString)

    ' Open a stream to point to the data stream coming from the Web resource.
    Dim myStream As Stream = myWebClient.OpenRead(uriString)

    Console.WriteLine(ControlChars.Cr + "Displaying Data :" + ControlChars.Cr)
Dim sr As New StreamReader(myStream)
Console.WriteLine(sr.ReadToEnd())


    ' Close the stream.
    myStream.Close()

Remarks

Caution

WebRequest, HttpWebRequest, ServicePoint, and WebClient are obsolete, and you shouldn't use them for new development. Use HttpClient instead.

The OpenRead method creates a Stream instance used to read the contents of the resource specified by the address parameter. This method blocks while opening the stream. To continue executing while waiting for the stream, use one of the OpenReadAsync methods.

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 null, it is appended to address.

This method uses the RETR command to download an FTP resource. For an HTTP resource, the GET method is used.

Note

You must call Stream.Close when finished with the Stream to avoid running out of system resources.

Note

This member outputs trace information when you enable network tracing in your application. For more information, see Network Tracing in .NET Framework.

OpenRead(Uri)

Source:

WebClient.cs

Opens a readable stream for the data downloaded from a resource with the URI specified as a Uri.

public:
 System::IO::Stream ^ OpenRead(Uri ^ address);

public System.IO.Stream OpenRead (Uri address);

member this.OpenRead : Uri -> System.IO.Stream

Public Function OpenRead (address As Uri) As Stream

Parameters

address

Uri

The URI specified as a Uri from which to download data.

Returns

Stream

A Stream used to read data from a resource.

Exceptions

ArgumentNullException

The address parameter is null.

WebException

The URI formed by combining BaseAddress, address is invalid.

-or-

An error occurred while downloading data.

Remarks

Caution

WebRequest, HttpWebRequest, ServicePoint, and WebClient are obsolete, and you shouldn't use them for new development. Use HttpClient instead.

The OpenRead method creates a Stream instance used to read the contents of the resource specified by the address parameter. This method blocks while opening the stream. To continue executing while waiting for the stream, use one of the OpenReadAsync methods.

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 null, it is appended to address.

This method uses the RETR command to download an FTP resource. For an HTTP resource, the GET method is used.

Note

You must call Stream.Close when finished with the Stream to avoid running out of system resources.

Note

This member outputs trace information when you enable network tracing in your application. For more information, see Network Tracing in .NET Framework.