WebClient.QueryString Property

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

[Visual Basic]
Public Property QueryString As NameValueCollection
[C#]
public NameValueCollection QueryString {get; set;}
[C++]
public: __property NameValueCollection* get_QueryString();
public: __property void set_QueryString(NameValueCollection*);
[JScript]
public function get QueryString() : NameValueCollection;
public function set QueryString(NameValueCollection);

Property Value

A NameValueCollection that contains query name/value pairs associated with the request.

Remarks

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 (&).

Example

[Visual Basic, C#, C++] The following 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.

[Visual Basic] 
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()
' Append necessary parameter/value pairs to the name/value container. 
' as QueryString = "?q=Microsoft&btnG=Google+Search". 
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.
myQueryStringCollection.Add("btnG", "Google" + ChrW(43) + "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."))

[C#] 
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.");

[C++] 
String* uriString = S"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(S"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(S"q", searchPhrase);
else
   // If error, default to search for 'Microsoft'.
   myQueryStringCollection->Add(S"q", S"Microsoft");
// Assign auxilliary parameters required for the search.
Console::WriteLine(S"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, S"searchresult.htm");
Console::WriteLine(S"\nDownload of {0} was successful. Please see 'searchresult.htm' for results.", uriString);

[JScript] No example is available for JScript. To view a Visual Basic, C#, or C++ example, click the Language Filter button in the upper-left corner of the page.

Requirements

Platforms: Windows 98, Windows NT 4.0, Windows Millennium Edition, Windows 2000, Windows XP Home Edition, Windows XP Professional, Windows Server 2003 family, Common Language Infrastructure (CLI) Standard

See Also

WebClient Class | WebClient Members | System.Net Namespace