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WebClient.QueryString Property

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

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

'Declaration
Public Property QueryString As NameValueCollection

Property Value

Type: System.Collections.Specialized.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.

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 (&).

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.

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."))

.NET Framework

Supported in: 4.5.2, 4.5.1, 4.5, 4, 3.5, 3.0, 2.0, 1.1, 1.0

.NET Framework Client Profile

Supported in: 4, 3.5 SP1

Windows 8.1, Windows Server 2012 R2, Windows 8, Windows Server 2012, Windows 7, Windows Vista SP2, Windows Server 2008 (Server Core Role not supported), Windows Server 2008 R2 (Server Core Role supported with SP1 or later; Itanium not supported)

The .NET Framework does not support all versions of every platform. For a list of the supported versions, see .NET Framework System Requirements.

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