WebClient.BaseAddress 属性

定义

命名空间:

System.Net

程序集:

System.Net.WebClient.dll

Source:

WebClient.cs

获取或设置由 WebClient发出的请求的基本 URI。

public:
 property System::String ^ BaseAddress { System::String ^ get(); void set(System::String ^ value); };

public string BaseAddress { get; set; }

member this.BaseAddress : string with get, set

Public Property BaseAddress As String

属性值

String

一个 String，包含 WebClient 发出的请求的基本 URI;如果未指定基址，则为 Empty。

例外

ArgumentException

BaseAddress 设置为无效 URI。 内部异常可能包含有助于查找错误的信息。

示例

下面的代码示例从 Internet 服务器下载数据，并将其显示在主机上。 它假定服务器的地址（如 http://www.contoso.com）处于 hostUri，资源的路径（如/default.htm）处于 uriSuffix中。

// Create a new WebClient instance.
WebClient^ myWebClient = gcnew WebClient;

// Set the BaseAddress of the Web Resource in the WebClient.
myWebClient->BaseAddress = hostUri;
Console::WriteLine( "Downloading from {0}/ {1}", hostUri, uriSuffix );
Console::WriteLine( "\nPress Enter key to continue" );
Console::ReadLine();

// Download the target Web Resource into a Byte array.
array<Byte>^ myDatabuffer = myWebClient->DownloadData( uriSuffix );

// Display the downloaded data.
String^ download = Encoding::ASCII->GetString( myDatabuffer );
Console::WriteLine( download );
Console::WriteLine( "Download of {0}{1} was successful.", myWebClient->BaseAddress, uriSuffix );

// Create a new WebClient instance.
WebClient myWebClient = new WebClient();

// Set the BaseAddress of the Web Resource in the WebClient.
myWebClient.BaseAddress = hostUri;
Console.WriteLine("Downloading from " + hostUri + "/" + uriSuffix);
Console.WriteLine("\nPress Enter key to continue");
Console.ReadLine();	

// Download the target Web Resource into a byte array.
byte[] myDatabuffer = myWebClient.DownloadData (uriSuffix);

// Display the downloaded data.
string download = Encoding.ASCII.GetString(myDatabuffer);
Console.WriteLine(download);

Console.WriteLine("Download of " + myWebClient.BaseAddress.ToString() + uriSuffix + " was successful.");

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

    ' Set the BaseAddress of the Web resource in the WebClient.
    myWebClient.BaseAddress = hostUri
    Console.WriteLine(("Downloading from " + hostUri + "/" + uriSuffix))
    Console.WriteLine(ControlChars.Cr + "Press Enter key to continue")
    Console.ReadLine()

    ' Download the target Web resource into a byte array.
    Dim myDatabuffer As Byte() = myWebClient.DownloadData(uriSuffix)

    ' Display the downloaded data.
Dim download As String = Encoding.ASCII.GetString(myDatabuffer)
Console.WriteLine(download)

    Console.WriteLine(("Download of " + myWebClient.BaseAddress.ToString() + uriSuffix + " was successful."))

注解

谨慎

WebRequest、HttpWebRequest、ServicePoint和 WebClient 已过时，不应将其用于新开发。 请改用 HttpClient。

BaseAddress 属性包含与相对地址组合的基 URI。 调用上传或下载数据的方法时，WebClient 对象将此基 URI 与方法调用中指定的相对地址组合在一起。 如果指定绝对 URI，WebClient 不使用 BaseAddress 属性值。

若要删除以前设置的值，请将此属性设置为 null 或空字符串（“）。