WebClient.QueryString Property

Reference

Definition

Namespace:: System.Net

Assembly:: System.Net.WebClient.dll

Assembly:: System.dll

Assembly:: netstandard.dll

Source:: WebClient.cs

Source:: WebClient.cs

Source:: WebClient.cs

Important

Some information relates to prerelease product that may be substantially modified before it’s released. Microsoft makes no warranties, express or implied, with respect to the information provided here.

Gets or sets a collection of query name/value pairs associated with the request.

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

Property Value

NameValueCollection

A NameValueCollection that contains query name/value pairs associated with the request. If no pairs are associated with the request, the value is an empty NameValueCollection.

Examples

The following code example takes user input from the command line and builds a NameValueCollection that is assigned to the QueryString property. It then downloads the response from the server to a local file.

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."))

Remarks

Caution

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

The QueryString property contains a NameValueCollection instance containing name/value pairs that are appended to the URI as a query string. The contents of the QueryString property are preceded by a question mark (?), and name/value pairs are separated from one another by an ampersand (&).

Applies to

Jaa