WebClient.QueryString 属性

定义

命名空间:

System.Net

程序集:

System.Net.WebClient.dll

Source:

WebClient.cs

获取或设置与请求关联的查询名称/值对的集合。

public:
 property System::Collections::Specialized::NameValueCollection ^ QueryString { System::Collections::Specialized::NameValueCollection ^ get(); void set(System::Collections::Specialized::NameValueCollection ^ value); };

public System.Collections.Specialized.NameValueCollection QueryString { get; set; }

member this.QueryString : System.Collections.Specialized.NameValueCollection with get, set

Public Property QueryString As NameValueCollection

属性值

NameValueCollection

包含与请求关联的查询名称/值对的 NameValueCollection。 如果没有与请求关联的对，则值为空 NameValueCollection。

示例

下面的代码示例从命令行获取用户输入，并生成分配给 QueryString 属性的 NameValueCollection。 然后，它将响应从服务器下载到本地文件。

String^ uriString = "http://www.contoso.com/search";
// Create a new WebClient instance.
WebClient^ myWebClient = gcnew WebClient;
// Create a new NameValueCollection instance to hold the QueryString parameters and values.
NameValueCollection^ myQueryStringCollection = gcnew NameValueCollection;
Console::Write( "Enter the word(s), separated by space character to search for in {0}: ", uriString );
// Read user input phrase to search for at uriString.
String^ searchPhrase = Console::ReadLine();
if ( searchPhrase->Length > 1 )
{
   // Assign the user-defined search phrase.
   myQueryStringCollection->Add( "q", searchPhrase );
}
else
{
   // If error, default to search for 'Microsoft'.
   myQueryStringCollection->Add( "q", "Microsoft" );
}
// Assign auxilliary parameters required for the search.
Console::WriteLine( "Searching {0} .......", uriString );
// Attach QueryString to the WebClient.
myWebClient->QueryString = myQueryStringCollection;
// Download the search results Web page into 'searchresult.htm' for inspection.
myWebClient->DownloadFile( uriString, "searchresult.htm" );
Console::WriteLine( "\nDownload of {0} was successful. Please see 'searchresult.htm' for results.", uriString );

string uriString = "http://www.contoso.com/search";
// Create a new WebClient instance.
WebClient myWebClient = new WebClient();
// Create a new NameValueCollection instance to hold the QueryString parameters and values.
NameValueCollection myQueryStringCollection = new NameValueCollection();
Console.Write("Enter the word(s), separated by space character to search for in " +  uriString + ": ");
// Read user input phrase to search for at uriString.
string searchPhrase = Console.ReadLine();
if (searchPhrase.Length > 1)
    // Assign the user-defined search phrase.
    myQueryStringCollection.Add("q",searchPhrase);
else
    // If error, default to search for 'Microsoft'.
    myQueryStringCollection.Add("q","Microsoft");		
// Assign auxilliary parameters required for the search.
Console.WriteLine("Searching " + uriString + " .......");
// Attach QueryString to the WebClient.
myWebClient.QueryString = myQueryStringCollection;
// Download the search results Web page into 'searchresult.htm' for inspection.
myWebClient.DownloadFile (uriString, "searchresult.htm");
Console.WriteLine("\nDownload of " + uriString + " was successful. Please see 'searchresult.htm' for results.");

Dim uriString As String = "http://www.contoso.com/search"
' Create a new WebClient instance.
Dim myWebClient As New WebClient()
' Create a new NameValueCollection instance to hold the QueryString parameters and values.
Dim myQueryStringCollection As New NameValueCollection()
Console.Write(("Enter the word(s), separated by space characters, to search for in " + uriString + ": "))
' Read user input phrase to search in uriString.
Dim searchPhrase As String = Console.ReadLine()
If searchPhrase.Length > 1 Then
    'Assign the user-defined search phrase.
    myQueryStringCollection.Add("q", searchPhrase)
' If error, default to search 'Microsoft'.
Else
    myQueryStringCollection.Add("q", "Microsoft")
End If 
' Assign auxilliary parameters required for the search.
Console.WriteLine(("Searching " + uriString + " ......."))
' Attach QueryString to the WebClient.
myWebClient.QueryString = myQueryStringCollection
' Download the search results Web page into 'searchresult.htm' for inspection.
myWebClient.DownloadFile(uriString, "searchresult.htm")
Console.WriteLine((ControlChars.Cr + "Download of " + uriString + " was successful. Please see 'searchresult.htm' for results."))

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。

QueryString 属性包含一个 NameValueCollection 实例，该实例包含作为查询字符串追加到 URI 的名称/值对。 QueryString 属性的内容前面有问号（？），名称/值对由与（&）彼此分隔。