WebClient.OpenRead Method (String)


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

Namespace:   System.Net
Assembly:  System (in System.dll)

public Stream OpenRead(
	string address


Type: System.String

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

Return Value

Type: System.IO.Stream

A Stream used to read data from a resource.

Exception Condition

The address parameter is null.


The URI formed by combining BaseAddress, address is invalid.


An error occurred while downloading data.

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.


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


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

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

// 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);

// Close the stream. 

.NET Framework
Available since 1.1
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