System Namespace

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Provides an object representation of a uniform resource indentifier ( URI ) and easy access to the parts of the URI.

Uri Class Members

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Constructors Visibility Constructor Parameters public Uri ( String uriString ) public Uri ( String uriString , Boolean dontEscape ) public Uri ( String uriString , UriKind uriKind ) public Uri ( Uri baseUri , String relativeUri ) public Uri ( Uri baseUri , String relativeUri , Boolean dontEscape ) public Uri ( Uri baseUri , Uri relativeUri )   Fields Visibility Name Type public static SchemeDelimiter String public static UriSchemeFile String public static UriSchemeFtp String public static UriSchemeGopher String public static UriSchemeHttp String public static UriSchemeHttps String public static UriSchemeMailto String public static UriSchemeNetPipe String public static UriSchemeNetTcp String public static UriSchemeNews String public static UriSchemeNntp String   Properties Visibility Name Value Type Accessibility public AbsolutePath String [ Get ] public AbsoluteUri String [ Get ] public Authority String [ Get ] public DnsSafeHost String [ Get ] public Fragment String [ Get ] public Host String [ Get ] public HostNameType UriHostNameType [ Get ] public IsAbsoluteUri Boolean [ Get ] public IsDefaultPort Boolean [ Get ] public IsFile Boolean [ Get ] public IsLoopback Boolean [ Get ] public IsUnc Boolean [ Get ] public LocalPath String [ Get ] public OriginalString String [ Get ] public PathAndQuery String [ Get ] public Port Int32 [ Get ] public Query String [ Get ] public Scheme String [ Get ] public Segments String [ Get ] public UserEscaped Boolean [ Get ] public UserInfo String [ Get ]   Methods Visibility Name Parameters Return Type protected Canonicalize ( ) Void public static CheckHostName ( String name ) UriHostNameType public static CheckSchemeName ( String schemeName ) Boolean protected CheckSecurity ( ) Void public static Compare ( Uri uri1 , Uri uri2 , UriComponents partsToCompare , UriFormat compareFormat , StringComparison comparisonType ) Int32 public Equals ( Object comparand ) Boolean protected Escape ( ) Void public static EscapeDataString ( String stringToEscape ) String protected static EscapeString ( String str ) String public static EscapeUriString ( String stringToEscape ) String public static FromHex ( Char digit ) Int32 public GetComponents ( UriComponents components , UriFormat format ) String public GetHashCode ( ) Int32 public GetLeftPart ( UriPartial part ) String protected GetObjectData ( SerializationInfo serializationInfo , StreamingContext streamingContext ) Void public static HexEscape ( Char character ) String public static HexUnescape ( String pattern , Int32& index ) Char protected IsBadFileSystemCharacter ( Char character ) Boolean public IsBaseOf ( Uri uri ) Boolean protected static IsExcludedCharacter ( Char character ) Boolean public static IsHexDigit ( Char character ) Boolean public static IsHexEncoding ( String pattern , Int32 index ) Boolean protected IsReservedCharacter ( Char character ) Boolean public IsWellFormedOriginalString ( ) Boolean public static IsWellFormedUriString ( String uriString , UriKind uriKind ) Boolean public MakeRelative ( Uri toUri ) String public MakeRelativeUri ( Uri uri ) Uri protected Parse ( ) Void public ToString ( ) String public static TryCreate ( Uri baseUri , String relativeUri , Uri& result ) Boolean public static TryCreate ( String uriString , UriKind uriKind , Uri& result ) Boolean public static TryCreate ( Uri baseUri , Uri relativeUri , Uri& result ) Boolean protected Unescape ( String path ) String public static UnescapeDataString ( String stringToUnescape ) String

A URI is a compact representation of a resource available to your application on the Internet. The Uri class defines the properties and methods for handling URIs, including parsing, comparing, and combining. The Uri class properties are read-only, to modify a Uri instance use the UriBuilder class.

The Uri class stores only absolute URIs ( for example, "http://www.contoso.com/index.aspx" ). Relative URIs ( for example, "/new/index.aspx" ) must be expanded with respect to a base URI so that they are absolute. The MakeRelative method is provided to convert absolute URIs to relative URIs when necessary.

The Uri constructors will not escape URI strings if the string is a well-formed URI including a scheme identifier that contains escape sequences. The constructors will escape relative URI strings that contain a percent sign ( % ).

URIs are stored as canonical URIs in escaped encoding, with all characters with ASCII values greater than 127 replaced with their hexidecimal equivalents. To put the URI in canonical form, the Uri constructor performs the following steps.

• Converts the URI scheme to lower case.
• Converts the host name to lower case.
• Removes default and empty port numbers.
• Simplifies the URI by removing superfluous segments such as "/" and "/test" segments.

You can transform the contents of the Uri class from an escape encoded URI reference to a readable URI reference using the ToString method.

Some URIs include a fragment identifier or query. A fragment identifier is any text that follows a number sign ( # ) in the URI and is stored in the Fragment property. Query information is any text that follows a question mark ( ? ) in the URI, and is stored in the Query property.

The following example creates an instance of the Uri class and uses it to create a WebRequest.

[ VB ]
Dim siteUri As New Uri ( "http://www.contoso.com/" )

Dim wr As WebRequest = WebRequest.Create ( siteUri )

[ C# ]
Uri siteUri = new Uri ( "http://www.contoso.com/" );

 WebRequest wr = WebRequest.Create ( siteUri );

UriBuilder

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