HttpRequestHeaderCollection Class

Definition

Namespace:

Windows.Web.Http.Headers

Provides a collection of the HTTP headers associated with an HTTP request.

public ref class HttpRequestHeaderCollection sealed : IIterable<IKeyValuePair<Platform::String ^, Platform::String ^> ^>, IMap<Platform::String ^, Platform::String ^>, IStringable

/// [Windows.Foundation.Metadata.ContractVersion(Windows.Foundation.UniversalApiContract, 65536)]
/// [Windows.Foundation.Metadata.MarshalingBehavior(Windows.Foundation.Metadata.MarshalingType.Agile)]
class HttpRequestHeaderCollection final : IIterable<IKeyValuePair<winrt::hstring, winrt::hstring const&>>, IMap<winrt::hstring, winrt::hstring const&>, IStringable

[Windows.Foundation.Metadata.ContractVersion(typeof(Windows.Foundation.UniversalApiContract), 65536)]
[Windows.Foundation.Metadata.MarshalingBehavior(Windows.Foundation.Metadata.MarshalingType.Agile)]
public sealed class HttpRequestHeaderCollection : IDictionary<string,string>, IEnumerable<KeyValuePair<string,string>>, IStringable

Public NotInheritable Class HttpRequestHeaderCollection
Implements IDictionary(Of String, String), IEnumerable(Of KeyValuePair(Of String, String)), IStringable

Inheritance

Object Platform::Object IInspectable HttpRequestHeaderCollection

Attributes

ContractVersionAttribute MarshalingBehaviorAttribute

Implements

IDictionary<String,String> IMap<Platform::String,Platform::String> IMap<winrt::hstring,winrt::hstring> IIterable<IKeyValuePair<K,V>> IEnumerable<KeyValuePair<K,V>> IEnumerable<KeyValuePair<String,String>> IIterable<IKeyValuePair<Platform::String,Platform::String>> IIterable<IKeyValuePair<winrt::hstring,winrt::hstring>> IStringable

Windows requirements

Device family	Windows 10 (introduced in 10.0.10240.0)
API contract	Windows.Foundation.UniversalApiContract (introduced in v1.0)

Examples

The following sample code shows a method to get and set request headers on an HttpRequestMessage object using the properties on the HttpRequestHeaderCollection object. The Windows.Web.Http.Headers namespace also has a number of strongly-typed header collection and value classes for specific HTTP headers that can be used to get and set headers with validation.

using System;
using System.Collections.Generic;
using Windows.Foundation;
using Windows.Foundation.Collections;
using Windows.Web.Http;
using Windows.Web.Http.Headers;

        public void DemonstrateHeaderRequest()
        {
            DemonstrateHeaderRequestAccept();
            DemonstrateHeaderRequestAcceptEncoding();
            DemonstrateHeaderRequestAcceptLanguage();
            DemonstrateHeaderRequestAuthorization();
            DemonstrateHeaderRequestCacheControl();
            DemonstrateHeaderRequestConnection();
            DemonstrateHeaderRequestCookie();
            DemonstrateHeaderRequestDate();
            DemonstrateHeaderRequestFrom();
            DemonstrateHeaderRequestHost();
            DemonstrateHeaderRequestIfModifiedSince();
            DemonstrateHeaderRequestIfUnmodifiedSince();
            DemonstrateHeaderRequestMaxForwards();
            DemonstrateHeaderRequestProxyAuthorization();
            DemonstrateHeaderRequestReferer();
            DemonstrateHeaderRequestUserAgent();
        }

        public void DemonstrateHeaderRequestAccept()
        {
            var request = new HttpRequestMessage();
            bool parsedOk = false;

            // Set the header with a string.
            parsedOk = request.Headers.Accept.TryParseAdd ("audio/*");
            parsedOk = request.Headers.Accept.TryParseAdd ("audio/*; q=0.2");
            parsedOk = request.Headers.Accept.TryParseAdd ("audio/*; q=0.4; mysetting=myvalue");

            // Set the header with a strong type.
            request.Headers.Accept.Add(new HttpMediaTypeWithQualityHeaderValue("audio/*", .6));

            // Get the strong type out
            foreach (var value in request.Headers.Accept)
            {
                System.Diagnostics.Debug.WriteLine("One of the Accept values: {0}={1}", value.MediaType, value.Quality);
            }

            // The ToString() is useful for diagnostics, too.
            System.Diagnostics.Debug.WriteLine("The Accept ToString() results: {0}", request.Headers.Accept.ToString());
        }

        public void DemonstrateHeaderRequestAcceptEncoding()
        {
            var request = new HttpRequestMessage();
            bool parsedOk = false;

            // Set the header with a string.
            parsedOk = request.Headers.AcceptEncoding.TryParseAdd("compress");
            parsedOk = request.Headers.AcceptEncoding.TryParseAdd("gzip;q=1.0");

            // Set the header with a strong type.
            request.Headers.AcceptEncoding.Add(new HttpContentCodingWithQualityHeaderValue("*", 0));

            // Get the strong type out
            foreach (var value in request.Headers.AcceptEncoding)
            {
                System.Diagnostics.Debug.WriteLine("One of the AcceptEncoding values: {0}={1}", value.ContentCoding, value.Quality);
            }

            // The ToString() is useful for diagnostics, too.
            System.Diagnostics.Debug.WriteLine("The AcceptEncoding ToString() results: {0}", request.Headers.AcceptEncoding.ToString());
        }

        public void DemonstrateHeaderRequestAcceptLanguage()
        {
            var request = new HttpRequestMessage();
            bool parsedOk = false;

            // Set the header with a string.
            parsedOk = request.Headers.AcceptLanguage.TryParseAdd("da");
            parsedOk = request.Headers.AcceptLanguage.TryParseAdd("en-gb;q=0.8");

            // Set the header with a strong type.
            request.Headers.AcceptLanguage.Add(new HttpLanguageRangeWithQualityHeaderValue("en", .7));

            // Get the strong type out
            foreach (var value in request.Headers.AcceptLanguage)
            {
                System.Diagnostics.Debug.WriteLine("One of the AcceptLanguage values: {0}={1}", value.LanguageRange, value.Quality);
            }

            // The ToString() is useful for diagnostics, too.
            System.Diagnostics.Debug.WriteLine("The AcceptLanguage ToString() results: {0}", request.Headers.AcceptLanguage.ToString());
        }

        public void DemonstrateHeaderRequestAuthorization()
        {
            var request = new HttpRequestMessage();

            // Set the header with a strong type.
            string username = "user";
            string password = "password";
            var buffer = Windows.Security.Cryptography.CryptographicBuffer.ConvertStringToBinary (username + ":" + password, Windows.Security.Cryptography.BinaryStringEncoding.Utf8);
            string base64token = Windows.Security.Cryptography.CryptographicBuffer.EncodeToBase64String(buffer);
            request.Headers.Authorization = new HttpCredentialsHeaderValue("Basic", base64token);


            // Get the strong type out
            System.Diagnostics.Debug.WriteLine("One of the Authorization values: {0}={1}", 
                request.Headers.Authorization.Scheme,
                request.Headers.Authorization.Token);

            // The ToString() is useful for diagnostics, too.
            System.Diagnostics.Debug.WriteLine("The Authorization ToString() results: {0}", request.Headers.Authorization.ToString());
        }

        public void DemonstrateHeaderRequestCacheControl()
        {
            var request = new HttpRequestMessage();
            bool parsedOk = false;

            // Set the header with a string.
            parsedOk = request.Headers.CacheControl.TryParseAdd("no-store");

            // Set the header with a strong type.
            request.Headers.CacheControl.Add(new HttpNameValueHeaderValue("max-age", "10"));

            // Get the strong type out
            foreach (var value in request.Headers.CacheControl)
            {
                System.Diagnostics.Debug.WriteLine("One of the CacheControl values: {0}={1}", value.Name, value.Value);
            }

            // The ToString() is useful for diagnostics, too.
            System.Diagnostics.Debug.WriteLine("The CacheControl ToString() results: {0}", request.Headers.CacheControl.ToString());
        }


        public void DemonstrateHeaderRequestConnection()
        {
            var request = new HttpRequestMessage();
            bool parsedOk = false;

            // Set the header with a string.
            parsedOk = request.Headers.Connection.TryParseAdd("close");

            // Set the header with a strong type.
            request.Headers.Connection.Add(new HttpConnectionOptionHeaderValue("cache-control"));

            // Get the strong type out
            foreach (var value in request.Headers.Connection)
            {
                System.Diagnostics.Debug.WriteLine("One of the Connection values: {0}", value.Token);
            }

            // The ToString() is useful for diagnostics, too.
            System.Diagnostics.Debug.WriteLine("The Connection ToString() results: {0}", request.Headers.Connection.ToString());
        }

        public void DemonstrateHeaderRequestCookie()
        {
            var request = new HttpRequestMessage();
            bool parsedOk = false;

            // Set the header with a string.
            parsedOk = request.Headers.Cookie.TryParseAdd("cookieName=cookieValue");

            // Set the header with a strong type.
            request.Headers.Cookie.Add(new HttpCookiePairHeaderValue("cookie2", "value2"));

            // Get the strong type out
            foreach (var value in request.Headers.Cookie)
            {
                System.Diagnostics.Debug.WriteLine("One of the Cookie values: {0}={1}", value.Name, value.Value);
            }

            // The ToString() is useful for diagnostics, too.
            System.Diagnostics.Debug.WriteLine("The Cookie ToString() results: {0}", request.Headers.Cookie.ToString());
        }


        public void DemonstrateHeaderRequestDate()
        {
            var request = new HttpRequestMessage();

            // This is not typically set with a string.

            // Set the header with a strong type.
            DateTimeOffset value = DateTimeOffset.UtcNow;
            request.Headers.Date = value;

            // Get the strong type out
            System.Diagnostics.Debug.WriteLine("Date value in ticks: {0}", request.Headers.Date.Value.Ticks);

            // The ToString() is useful for diagnostics, too.
            System.Diagnostics.Debug.WriteLine("The Date ToString() results: {0}", request.Headers.Date.ToString());
        }

        public void DemonstrateHeaderRequestFrom()
        {
            var request = new HttpRequestMessage();

            // Set the header with a string.
            request.Headers.From = "person@example.com";

            // Get the strong type out
            System.Diagnostics.Debug.WriteLine("From value: {0}", request.Headers.From);
        }

        public void DemonstrateHeaderRequestHost()
        {
            var request = new HttpRequestMessage();

            // This is not typically set with a string.

            // Set the header with a strong type.
            // HostName is in the Windows.Networking namespace.
            var value = new Windows.Networking.HostName("example.com");
            request.Headers.Host = value;

            // Get the strong type out
            System.Diagnostics.Debug.WriteLine("Canonical Host name: {0}", request.Headers.Host.CanonicalName);

            // The ToString() is useful for diagnostics, too.
            System.Diagnostics.Debug.WriteLine("The Host ToString() results: {0}", request.Headers.Host.ToString());
        }

        public void DemonstrateHeaderRequestIfModifiedSince()
        {
            var request = new HttpRequestMessage();

            // This is not typically set with a string.

            // Set the header with a strong type.
            var value = DateTimeOffset.Now.AddDays(-1); // Since yesterday.
            request.Headers.IfModifiedSince = value;

            // Get the strong type out
            System.Diagnostics.Debug.WriteLine("IfModifiedSince value in ticks: {0}", request.Headers.IfModifiedSince.Value.Ticks);

            // The ToString() is useful for diagnostics, too.
            System.Diagnostics.Debug.WriteLine("The IfModifiedSince ToString() results: {0}", request.Headers.IfModifiedSince.ToString());
        }

        public void DemonstrateHeaderRequestIfUnmodifiedSince()
        {
            var request = new HttpRequestMessage();

            // This is not typically set with a string.

            // Set the header with a strong type.
            var value = DateTimeOffset.Now.AddDays(-1); // Since yesterday.
            request.Headers.IfUnmodifiedSince = value;

            // Get the strong type out
            System.Diagnostics.Debug.WriteLine("IfUnmodifiedSince value in ticks: {0}", request.Headers.IfUnmodifiedSince.Value.Ticks);

            // The ToString() is useful for diagnostics, too.
            System.Diagnostics.Debug.WriteLine("The IfUnmodfiedSince ToString() results: {0}", request.Headers.IfUnmodifiedSince.ToString());
        }

        public void DemonstrateHeaderRequestMaxForwards()
        {
            var request = new HttpRequestMessage();

            // Set the header with an integer.
            request.Headers.MaxForwards= 2;

            // Get the strong type out
            System.Diagnostics.Debug.WriteLine("MaxForwards value: {0}", request.Headers.MaxForwards);
        }

        public void DemonstrateHeaderRequestProxyAuthorization()
        {
            var request = new HttpRequestMessage();

            // Set the header with a strong type.
            string username = "user";
            string password = "password";
            var buffer = Windows.Security.Cryptography.CryptographicBuffer.ConvertStringToBinary(username + ":" + password, Windows.Security.Cryptography.BinaryStringEncoding.Utf16LE);
            string base64token = Windows.Security.Cryptography.CryptographicBuffer.EncodeToBase64String(buffer);
            request.Headers.ProxyAuthorization = new HttpCredentialsHeaderValue("Basic", base64token);


            // Get the strong type out
            System.Diagnostics.Debug.WriteLine("One of the ProxyAuthorixation values: {0}={1}",
                request.Headers.ProxyAuthorization.Scheme,
                request.Headers.ProxyAuthorization.Token);

            // The ToString() is useful for diagnostics, too.
            System.Diagnostics.Debug.WriteLine("The ProxyAuthorization ToString() results: {0}", request.Headers.ProxyAuthorization.ToString());
        }


        public void DemonstrateHeaderRequestReferer()
        {
            var request = new HttpRequestMessage();

            // This is not typically set with a string.

            // Set the header with a strong type.
            // Uri is either in the Windows.Foundation namespace (JavaScript and C++)
            // or in the System.Net namespace (C#).
            var value = new Uri("http://example.com/");
            request.Headers.Referer = value;

            // Get the strong type out
            System.Diagnostics.Debug.WriteLine("Referer absolute uri: {0}", request.Headers.Referer.AbsoluteUri);

            // The ToString() is useful for diagnostics, too.
            System.Diagnostics.Debug.WriteLine("The Host ToString() results: {0}", request.Headers.Referer.ToString());
        }

        public void DemonstrateHeaderRequestUserAgent()
        {
            var request = new HttpRequestMessage();
            bool parsedOk = false;

            // Set the header with a string.
            parsedOk = request.Headers.UserAgent.TryParseAdd("testprogram/1.0");

            // Set the header with a strong type.
            request.Headers.UserAgent.Add(new HttpProductInfoHeaderValue("myprogram", "2.2"));

            // Get the strong type out
            foreach (var value in request.Headers.UserAgent)
            {
                System.Diagnostics.Debug.WriteLine("One of the UserAgent values: {0} / {1}", value.Product.Name, value.Product.Version);
            }

            // The ToString() is useful for diagnostics, too.
            System.Diagnostics.Debug.WriteLine("The UserAgent ToString() results: {0}", request.Headers.UserAgent.ToString());
        }

Remarks

The HttpRequestHeaderCollection is a collection of the HTTP headers associated with an HTTP request. The HttpRequestHeaderCollection object can be used to get or set the specific headers on an HTTP request. Most of the properties on the HttpRequestHeaderCollection object provide access to the value of a specific HTTP header.

The Headers property on HttpRequestMessage returns an HttpRequestHeaderCollection object. The DefaultRequestHeaders property on HttpClient also returns an HttpRequestHeaderCollection object. These are the two methods to construct an HttpRequestHeaderCollection object.

The HttpRequestHeaderCollection represents HTTP headers on an HTTP request that an app developer can set, not all of the headers that may eventually be sent with the request. The HttpBaseProtocolFilter will add some additional headers.

Headers on an HTTP request can be changed by the underlying stack. This would be why an app might want to get a header value from the HttpRequestHeaderCollection after the request has completed.

Enumerating the collection in C# or Microsoft Visual Basic

You can iterate through an HttpRequestHeaderCollection object in C# or Microsoft Visual Basic. In many cases, such as using foreach syntax, the compiler does this casting for you and you won't need to cast to IEnumerable explicitly. If you do need to cast explicitly, for example if you want to call GetEnumerator, cast the collection object to IEnumerable<T> with a KeyValuePair of String and String as the constraint.

Properties

Accept	Gets the HttpMediaTypeWithQualityHeaderValueCollection of HttpMediaTypeWithQualityHeaderValue objects that represent the value of an Accept HTTP header on an HTTP request.
AcceptEncoding	Gets the HttpContentCodingWithQualityHeaderValueCollection of HttpContentCodingWithQualityHeaderValue objects that represent the value of an Accept-Encoding HTTP header on an HTTP request.
AcceptLanguage	Gets the HttpLanguageRangeWithQualityHeaderValueCollection of HttpLanguageRangeWithQualityHeaderValue objects that represent the value of an Accept-Language HTTP header on an HTTP request.
Authorization	Gets or sets the HttpCredentialsHeaderValue object that represents the value of an Authorization HTTP header on an HTTP request.
CacheControl	Gets the HttpCacheDirectiveHeaderValueCollection that represents the value of a Cache-Control HTTP header on an HTTP request.
Connection	Gets the HttpConnectionOptionHeaderValueCollection of HttpConnectionOptionHeaderValue objects that represent the value of a Connection HTTP header on an HTTP request.
Cookie	Gets the HttpCookiePairHeaderValueCollection of HttpCookiePairHeaderValue objects that represent the value of an Cookie HTTP header sent on an HTTP request.
Date	Gets or sets the DateTime object that represents the value of a Date HTTP header on an HTTP request.
Expect	Gets the HttpExpectationHeaderValueCollection of HttpExpectationHeaderValue objects that represent the value of an Expect HTTP header on an HTTP request.
From	Gets or sets the String that represents the value of a From HTTP header on an HTTP request.
Host	Gets or sets the HostName that represents the value of a Host HTTP header on an HTTP request.
IfModifiedSince	Gets or sets the DateTime object that represents the value of an If-Modified-Since HTTP header on an HTTP request.
IfUnmodifiedSince	Gets or sets the DateTime object that represents the value of an If-Unmodified-Since HTTP header on an HTTP request.
MaxForwards	Gets or sets an integer value that represents the value of a Max-Forwards HTTP header on an HTTP request.
ProxyAuthorization	Gets or sets the HttpCredentialsHeaderValue object that represent the value of a Proxy-Authorization HTTP header on an HTTP request.
Referer	Gets or sets the Uri that represents the value of a Referer HTTP header on an HTTP request.
Size	Gets the number of objects in the HttpRequestHeaderCollection.
TransferEncoding	Gets the HttpTransferCodingHeaderValueCollection of HttpTransferCodingHeaderValue objects that represent the value of a Transfer-Encoding HTTP header on an HTTP request.
UserAgent	Gets the HttpProductInfoHeaderValueCollection of HttpProductInfoHeaderValue objects that represent the value of a User-Agent HTTP header on an HTTP request.

Methods

Append(String, String)	Adds a new item to the end of the HttpRequestHeaderCollection.
Clear()	Removes all objects from the HttpRequestHeaderCollection.
First()	Retrieves an iterator to the first item in the HttpRequestHeaderCollection.
GetView()	Returns an immutable view of the HttpRequestHeaderCollection.
HasKey(String)	Determines whether the HttpRequestHeaderCollection contains the specified key.
Insert(String, String)	Inserts or replaces an item in the HttpRequestHeaderCollection with the specified key and value.
Lookup(String)	Finds an item in the HttpRequestHeaderCollection if it exists.
Remove(String)	Removes a specific object from the HttpRequestHeaderCollection.
ToString()	Returns a string that represents the current HttpRequestHeaderCollection object.
TryAppendWithoutValidation(String, String)	Try to append the specified item to the HttpRequestHeaderCollection without validation.

See also

• DefaultRequestHeaders
• Headers
• HttpBaseProtocolFilter
• HttpClient
• HttpRequestMessage
• IMap<K,V>
• IIterable<T>
• IStringable