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)

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'.
    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
Available since 1.1
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