HttpRequestHeaderCollection HttpRequestHeaderCollection HttpRequestHeaderCollection HttpRequestHeaderCollection Class

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

Syntax

Declaration

public sealed class HttpRequestHeaderCollectionpublic sealed class HttpRequestHeaderCollectionPublic NotInheritable Class HttpRequestHeaderCollection

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.

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());
        }

Properties summary

Gets the HttpMediaTypeWithQualityHeaderValueCollection of HttpMediaTypeWithQualityHeaderValue objects that represent the value of an Accept HTTP header on an HTTP request.

Gets the HttpContentCodingWithQualityHeaderValueCollection of HttpContentCodingWithQualityHeaderValue objects that represent the value of an Accept-Encoding HTTP header on an HTTP request.

Gets the HttpLanguageRangeWithQualityHeaderValueCollection of HttpLanguageRangeWithQualityHeaderValue objects that represent the value of an Accept-Language HTTP header on an HTTP request.

Gets or sets the HttpCredentialsHeaderValue object that represents the value of an Authorization HTTP header on an HTTP request.

Gets the HttpCacheDirectiveHeaderValueCollection that represents the value of a Cache-Control HTTP header on an HTTP request.

Gets the HttpConnectionOptionHeaderValueCollection of HttpConnectionOptionHeaderValue objects that represent the value of a Connection HTTP header on an HTTP request.

Gets the HttpCookiePairHeaderValueCollection of HttpCookiePairHeaderValue objects that represent the value of an Cookie HTTP header sent on an HTTP request.

Gets or sets the DateTime object that represents the value of a Date HTTP header on an HTTP request.

Gets the HttpExpectationHeaderValueCollection of HttpExpectationHeaderValue objects that represent the value of an Expect HTTP header on an HTTP request.

Gets or sets the String that represents the value of a From HTTP header on an HTTP request.

Gets or sets the HostName that represents the value of a Host HTTP header on an HTTP request.

Gets or sets the DateTime object that represents the value of an If-Modified-Since HTTP header on an HTTP request.

Gets or sets the DateTime object that represents the value of an If-Unmodified-Since HTTP header on an HTTP request.

Gets or sets an integer value that represents the value of a Max-Forwards HTTP header on an HTTP request.

Gets or sets the HttpCredentialsHeaderValue object that represent the value of a Proxy-Authorization HTTP header on an HTTP request.

Gets or sets the Uri that represents the value of a Referer HTTP header on an HTTP request.

Gets the number of objects in the HttpRequestHeaderCollection.

Gets the HttpTransferCodingHeaderValueCollection of HttpTransferCodingHeaderValue objects that represent the value of a Transfer-Encoding HTTP header on an HTTP request.

Gets the HttpProductInfoHeaderValueCollection of HttpProductInfoHeaderValue objects that represent the value of a User-Agent HTTP header on an HTTP request.

Methods summary

Adds a new item to the end of the HttpRequestHeaderCollection.

Removes all objects from the HttpRequestHeaderCollection.

Retrieves an iterator to the first item in the HttpRequestHeaderCollection.

Returns an immutable view of the HttpRequestHeaderCollection.

Determines whether the HttpRequestHeaderCollection contains the specified key.

Inserts or replaces an item in the HttpRequestHeaderCollection with the specified key and value.

Finds an item in the HttpRequestHeaderCollection if it exists.

Removes a specific object from the HttpRequestHeaderCollection.

Returns a string that represents the current HttpRequestHeaderCollection object.

Try to append the specified item to the HttpRequestHeaderCollection without validation.

Properties

  • Accept
    Accept
    Accept
    Accept

    Gets the HttpMediaTypeWithQualityHeaderValueCollection of HttpMediaTypeWithQualityHeaderValue objects that represent the value of an Accept HTTP header on an HTTP request.

    public HttpMediaTypeWithQualityHeaderValueCollection Accept { get; }public HttpMediaTypeWithQualityHeaderValueCollection Accept { get; }Public ReadOnly Property Accept As HttpMediaTypeWithQualityHeaderValueCollection

    Property Value

  • AcceptEncoding
    AcceptEncoding
    AcceptEncoding
    AcceptEncoding

    Gets the HttpContentCodingWithQualityHeaderValueCollection of HttpContentCodingWithQualityHeaderValue objects that represent the value of an Accept-Encoding HTTP header on an HTTP request.

    public HttpContentCodingWithQualityHeaderValueCollection AcceptEncoding { get; }public HttpContentCodingWithQualityHeaderValueCollection AcceptEncoding { get; }Public ReadOnly Property AcceptEncoding As HttpContentCodingWithQualityHeaderValueCollection

    Property Value

  • AcceptLanguage
    AcceptLanguage
    AcceptLanguage
    AcceptLanguage

    Gets the HttpLanguageRangeWithQualityHeaderValueCollection of HttpLanguageRangeWithQualityHeaderValue objects that represent the value of an Accept-Language HTTP header on an HTTP request.

    public HttpLanguageRangeWithQualityHeaderValueCollection AcceptLanguage { get; }public HttpLanguageRangeWithQualityHeaderValueCollection AcceptLanguage { get; }Public ReadOnly Property AcceptLanguage As HttpLanguageRangeWithQualityHeaderValueCollection

    Property Value

  • Authorization
    Authorization
    Authorization
    Authorization

    Gets or sets the HttpCredentialsHeaderValue object that represents the value of an Authorization HTTP header on an HTTP request.

    public HttpCredentialsHeaderValue Authorization { get; set; }public HttpCredentialsHeaderValue Authorization { get; set; }Public ReadWrite Property Authorization As HttpCredentialsHeaderValue

    Property Value

  • CacheControl
    CacheControl
    CacheControl
    CacheControl

    Gets the HttpCacheDirectiveHeaderValueCollection that represents the value of a Cache-Control HTTP header on an HTTP request.

    public HttpCacheDirectiveHeaderValueCollection CacheControl { get; }public HttpCacheDirectiveHeaderValueCollection CacheControl { get; }Public ReadOnly Property CacheControl As HttpCacheDirectiveHeaderValueCollection

    Property Value

  • Connection
    Connection
    Connection
    Connection

    Gets the HttpConnectionOptionHeaderValueCollection of HttpConnectionOptionHeaderValue objects that represent the value of a Connection HTTP header on an HTTP request.

    public HttpConnectionOptionHeaderValueCollection Connection { get; }public HttpConnectionOptionHeaderValueCollection Connection { get; }Public ReadOnly Property Connection As HttpConnectionOptionHeaderValueCollection

    Property Value

  • Date
    Date
    Date
    Date

    Gets or sets the DateTime object that represents the value of a Date HTTP header on an HTTP request.

    public IReference<DateTime> Date { get; set; }public IReference<DateTime> Date { get; set; }Public ReadWrite Property Date As IReference<DateTime>

    Property Value

    • The object that represents the value of a Date HTTP header on an HTTP request. A null value means that the header is absent.

    Remarks

    The Date property represents the Date header on an HTTP request message. The Date header is the date and time the message was sent.

    Javascript and .NET languages do not use the DateTime object directly. In Javascript a DateTime is projected as a object, and in .NET it is projected as a System.DateTimeOffset. Each language transparently handles the conversion to the granularity and date ranges for the respective language.

    In C++, a value has the same granularity as a and supports the date ranges required by Javascript and .NET.

    For more detailed information, see the DateTime structure.

    The following sample code shows a method to set the Date header on an HttpRequestMessage object using the Date property on the HttpRequestHeaderCollection object.

        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());
        }
    
  • Expect
    Expect
    Expect
    Expect

    Gets the HttpExpectationHeaderValueCollection of HttpExpectationHeaderValue objects that represent the value of an Expect HTTP header on an HTTP request.

    public HttpExpectationHeaderValueCollection Expect { get; }public HttpExpectationHeaderValueCollection Expect { get; }Public ReadOnly Property Expect As HttpExpectationHeaderValueCollection

    Property Value

  • From
    From
    From
    From

    Gets or sets the String that represents the value of a From HTTP header on an HTTP request.

    public string From { get; set; }public string From { get; set; }Public ReadWrite Property From As string

    Property Value

    • string
      string
      string
      string

      The value of a From HTTP header on an HTTP request. An empty string means that the header is absent.

    Remarks

    The following sample code shows a method to set the From header on an HttpRequestMessage object using the From property on the HttpRequestHeaderCollection object.

        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);
        }
    
  • Host
    Host
    Host
    Host

    Gets or sets the HostName that represents the value of a Host HTTP header on an HTTP request.

    public HostName Host { get; set; }public HostName Host { get; set; }Public ReadWrite Property Host As HostName

    Property Value

    Remarks

    The following sample code shows a method to set the Host header on an HttpRequestMessage object using the Host property on the HttpRequestHeaderCollection object.

        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());
        }
    
  • IfModifiedSince
    IfModifiedSince
    IfModifiedSince
    IfModifiedSince

    Gets or sets the DateTime object that represents the value of an If-Modified-Since HTTP header on an HTTP request.

    public IReference<DateTime> IfModifiedSince { get; set; }public IReference<DateTime> IfModifiedSince { get; set; }Public ReadWrite Property IfModifiedSince As IReference<DateTime>

    Property Value

    • The DateTime object that represents the value of an If-Modified-Since HTTP header on an HTTP request. A null value means that the header is absent.

    Remarks

    The IfModifiedSince property represents the value of an If-Modified-Since HTTP header on an HTTP request message. The If-Modified-Since header is the date and time the content was modified since.

    Javascript and .NET languages do not use the DateTime object directly. In Javascript a DateTime is projected as a object, and in .NET it is projected as a System.DateTimeOffset. Each language transparently handles the conversion to the granularity and date ranges for the respective language.

    In C++, a value has the same granularity as a and supports the date ranges required by Javascript and .NET.

    For more detailed information, see the DateTime structure.

    The following sample code shows a method to set the If-Modified-Since header on an HttpRequestMessage object using the IfModifiedSince property on the HttpRequestHeaderCollection object.

        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());
        }
    
  • IfUnmodifiedSince
    IfUnmodifiedSince
    IfUnmodifiedSince
    IfUnmodifiedSince

    Gets or sets the DateTime object that represents the value of an If-Unmodified-Since HTTP header on an HTTP request.

    public IReference<DateTime> IfUnmodifiedSince { get; set; }public IReference<DateTime> IfUnmodifiedSince { get; set; }Public ReadWrite Property IfUnmodifiedSince As IReference<DateTime>

    Property Value

    • The DateTime object that represents the value of an If-Unmodified-Since HTTP header on an HTTP request. A null value means that the header is absent.

    Remarks

    The IfUnmodifiedSince property represents the value of an If-Unmodified-Since HTTP header on an HTTP request message. The If-Unmodified-Since header is the date and time the content was not modified since.

    Javascript and .NET languages do not use the DateTime object directly. In Javascript a DateTime is projected as a object, and in .NET it is projected as a System.DateTimeOffset. Each language transparently handles the conversion to the granularity and date ranges for the respective language.

    In C++, a value has the same granularity as a and supports the date ranges required by Javascript and .NET.

    For more detailed information, see the DateTime structure.

    The following sample code shows a method to set the If-Unmodified-Since header on an HttpRequestMessage object using the IfUnmodifiedSince property on the HttpRequestHeaderCollection object.

        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());
        }
    
  • MaxForwards
    MaxForwards
    MaxForwards
    MaxForwards

    Gets or sets an integer value that represents the value of a Max-Forwards HTTP header on an HTTP request.

    public IReference<uint> MaxForwards { get; set; }public IReference<uint> MaxForwards { get; set; }Public ReadWrite Property MaxForwards As IReference<uint>

    Property Value

    • An integer value that represents the value of a Max-Forwards HTTP header on an HTTP request. A null value means that the header is absent.

    Remarks

    The following sample code shows a method to set the Max-Forwards header on an HttpRequestMessage object using the MaxForwards property on the HttpRequestHeaderCollection object.

        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);
        }
    
  • ProxyAuthorization
    ProxyAuthorization
    ProxyAuthorization
    ProxyAuthorization

    Gets or sets the HttpCredentialsHeaderValue object that represent the value of a Proxy-Authorization HTTP header on an HTTP request.

    public HttpCredentialsHeaderValue ProxyAuthorization { get; set; }public HttpCredentialsHeaderValue ProxyAuthorization { get; set; }Public ReadWrite Property ProxyAuthorization As HttpCredentialsHeaderValue

    Property Value

  • Referer
    Referer
    Referer
    Referer

    Gets or sets the Uri that represents the value of a Referer HTTP header on an HTTP request.

    public Uri Referer { get; set; }public Uri Referer { get; set; }Public ReadWrite Property Referer As Uri

    Property Value

    • The object that represents the value of a Referer HTTP header on an HTTP request. A null value means that the header is absent.

    Remarks

    The following sample code shows a method to set the Referer header on an HttpRequestMessage object using the Referer property on the HttpRequestHeaderCollection object.

        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());
        }
    
  • Size
    Size
    Size
    Size

    Gets the number of objects in the HttpRequestHeaderCollection.

    public uint Size { get; }public uint Size { get; }Public ReadOnly Property Size As uint

    Property Value

    Remarks

    The Size property returns the true number of items.

    If you are programming using C# or Microsoft Visual Basic, the equivalent method is Count.

  • TransferEncoding
    TransferEncoding
    TransferEncoding
    TransferEncoding

    Gets the HttpTransferCodingHeaderValueCollection of HttpTransferCodingHeaderValue objects that represent the value of a Transfer-Encoding HTTP header on an HTTP request.

    public HttpTransferCodingHeaderValueCollection TransferEncoding { get; }public HttpTransferCodingHeaderValueCollection TransferEncoding { get; }Public ReadOnly Property TransferEncoding As HttpTransferCodingHeaderValueCollection

    Property Value

    Remarks

    The only transfer encoding value supported by HttpClient is chunked, even though the HttpTransferCodingHeaderValueCollection of HttpTransferCodingHeaderValue objects supports setting other values.

    There is no need to set the transfer encoding value manually to chunked if the HttpRequestMessage is sent as an with no content-length specified or available using the method on HttpClient or one of the methods on the HTTP content classes.

    The following sample code shows a method to set the Transfer-Encoding header on an HttpRequestMessage object using the TransferEncoding property on the HttpRequestHeaderCollection object.

        void DemoTransferEncoding(HttpRequestMessage m) {
            var h = m.Headers;
    
            uiLog.Text += "\nTRANSFERENCODING HEADER\n";
            // Transfer-Encoding: chunked
            var okTryParseAdd = h.TransferEncoding.TryParseAdd("chunked");
            okTryParseAdd = h.TransferEncoding.TryParseAdd("mini; a=b; c=d; e=f");
            h.TransferEncoding.Add(new HttpTransferCodingHeaderValue("cab"));
            h.TransferEncoding.TryParseAdd("newtype, othernewtype");
    
            // TransferEncoding is a HttpTransferCodingHeaderValueCollection
            // A collection of HttpTransferCodingHeaderValue
    
            // HttpTransferCodingHeaderValue has three items:
            // Value (string); e.g. "compress"
            // Parameter (IList<HttpNameValueHeaderValue>)
            //
    
            foreach (var item in h.TransferEncoding) {
                // item has: Value (string), Parameter IList<HttpNameValueHeaderValue>
                var parameterString = "";
                foreach (var parameter in item.Parameters) {
                    parameterString += string.Format("[{0}={1}] ", parameter.Name, parameter.Value);
                }
                if (parameterString == "") {
                    parameterString = "(no parameters)";
                } 
                uiLog.Text += string.Format("Value: {0} Parameters: {1} ToString: {2}\n", item.Value, parameterString, item.ToString());
            }
            uiLog.Text += string.Format("TransferEncoding: ToString: {0}\n\n", h.TransferEncoding.ToString());
        }
    
  • UserAgent
    UserAgent
    UserAgent
    UserAgent

    Gets the HttpProductInfoHeaderValueCollection of HttpProductInfoHeaderValue objects that represent the value of a User-Agent HTTP header on an HTTP request.

    public HttpProductInfoHeaderValueCollection UserAgent { get; }public HttpProductInfoHeaderValueCollection UserAgent { get; }Public ReadOnly Property UserAgent As HttpProductInfoHeaderValueCollection

    Property Value

    Remarks

    The following sample code shows a method to set the User-Agent header on an HttpRequestMessage object using the UserAgent property on the HttpRequestHeaderCollection object.

        void DemoUserAgent(HttpRequestMessage m) {
            var h = m.Headers;
    
            uiLog.Text += "\nUSERAGENT HEADER\n";
            // User-Agent: CERN-LineMode/2.15 libwww/2.17b3
            // User-Agent: Mozilla/5.0 (compatible; MSIE 9.0; Windows NT 6.1; WOW64; Trident/5.0; SLCC2; .NET CLR 2.0.50727; .NET CLR 3.5.30729; .NET CLR 3.0.30729; Media Center PC 6.0; Zune 4.0; InfoPath.3; MS-RTC LM 8; .NET4.0C; .NET4.0E)
            var ok = h.UserAgent.TryParseAdd("ie");
            ok = h.UserAgent.TryParseAdd("Mozilla/5.0 (compatible; MSIE 9.0; Windows NT 6.1; WOW64; Trident/5.0; SLCC2; .NET CLR 2.0.50727; .NET CLR 3.5.30729; .NET CLR 3.0.30729; Media Center PC 6.0; Zune 4.0; InfoPath.3; MS-RTC LM 8; .NET4.0C; .NET4.0E)");
            ok = h.UserAgent.TryParseAdd("CERN-LineMode/2.15 libwww/2.17b3");
            h.UserAgent.Add (new HttpProductInfoHeaderValue ("productComment"));
            h.UserAgent.Add(new HttpProductInfoHeaderValue("Mozilla", "1.0"));
    
            // UserAgent is a HttpProductInfoHeaderValueCollection
            // A collection of HttpProductInfoHeaderValue
    
            // HttpProductInfoHeaderValue has two items:
            // Product (string)
            // Comment (string)
            //
            // According to the RFC, each "item" is EITHER a product OR a comment, and a product is EITHER product or product/version
    
            foreach (var item in h.UserAgent) {
                // item has: Value (string), Parameter IList<HttpNameValueHeaderValue>
    
                uiLog.Text += string.Format("Product: {0} Comment: {1} ToString: {2}\n", item.Product, item.Comment, item.ToString());
            }
            uiLog.Text += string.Format("UserAgent: ToString: {0}\n\n", h.UserAgent.ToString());
        }
    

Methods

  • Append(System.String,System.String)
    Append(System.String,System.String)
    Append(System.String,System.String)
    Append(System.String,System.String)

    Adds a new item to the end of the HttpRequestHeaderCollection.

    public void Append(System.String,System.String)public void Append(System.String,System.String)Public Function Append(System.String,System.String) As void

    Parameters

    • name
      System.String
      System.String
      System.String
      System.String

      The name of the value to add.

    • value
      System.String
      System.String
      System.String
      System.String

      The item value to add.

  • Clear()
    Clear()
    Clear()
    Clear()

    Removes all objects from the HttpRequestHeaderCollection.

    public void Clear()public void Clear()Public Function Clear() As void
  • First()
    First()
    First()
    First()

    Retrieves an iterator to the first item in the HttpRequestHeaderCollection.

    public IIterator<IKeyValuePair<string, string>> First()public IIterator<IKeyValuePair<string, string>> First()Public Function First() As IIterator( Of IKeyValuePairstring, string )

    Returns

    • An object that can be used to enumerate the items in the collection. The iterator points to the first item in the HttpRequestHeaderCollection.

  • GetView()
    GetView()
    GetView()
    GetView()

    Returns an immutable view of the HttpRequestHeaderCollection.

    public IMapView<string, string> GetView()public IMapView<string, string> GetView()Public Function GetView() As IMapView( Of string, string )

    Returns

    Remarks

    When programming with .NET, this method is hidden.

  • HasKey(System.String)
    HasKey(System.String)
    HasKey(System.String)
    HasKey(System.String)

    Determines whether the HttpRequestHeaderCollection contains the specified key.

    public bool HasKey(System.String)public bool HasKey(System.String)Public Function HasKey(System.String) As bool

    Parameters

    • key
      System.String
      System.String
      System.String
      System.String

      The key associated with the item to locate.

    Returns

    • bool
      bool
      bool
      bool

      true if the key is found; otherwise, false.

    Remarks

    When programming with .NET, this method is hidden and developers should use ContainsKey.

  • Insert(System.String,System.String)
    Insert(System.String,System.String)
    Insert(System.String,System.String)
    Insert(System.String,System.String)

    Inserts or replaces an item in the HttpRequestHeaderCollection with the specified key and value.

    public bool Insert(System.String,System.String)public bool Insert(System.String,System.String)Public Function Insert(System.String,System.String) As bool

    Parameters

    • key
      System.String
      System.String
      System.String
      System.String

      The key of the item to be inserted.

    • value
      System.String
      System.String
      System.String
      System.String

      The value of the item to insert.

    Returns

    • bool
      bool
      bool
      bool

      true if an item with the specified key is an existing item that was replaced; otherwise false.

    Remarks

    When programming with .NET, this method is hidden and developers should use the Add methods.

  • Lookup(System.String)
    Lookup(System.String)
    Lookup(System.String)
    Lookup(System.String)

    Finds an item in the HttpRequestHeaderCollection if it exists.

    public string Lookup(System.String)public string Lookup(System.String)Public Function Lookup(System.String) As string

    Parameters

    • key
      System.String
      System.String
      System.String
      System.String

      The key of the item to lookup.

    Returns

    • string
      string
      string
      string

      The value, if an item with the specified key exists. Use the HasKey method to determine whether the key exists.

    Remarks

    Use the HasKey(System.String) method to determine whether the key exists in the HttpRequestHeaderCollection.

    When programming with .NET, this method is hidden and developers should use the Item indexer.

  • Remove(System.String)
    Remove(System.String)
    Remove(System.String)
    Remove(System.String)

    Removes a specific object from the HttpRequestHeaderCollection.

    public void Remove(System.String)public void Remove(System.String)Public Function Remove(System.String) As void

    Parameters

    • key
      System.String
      System.String
      System.String
      System.String

      The key of the item to remove.

  • ToString()
    ToString()
    ToString()
    ToString()

    Returns a string that represents the current HttpRequestHeaderCollection object.

    public string ToString()public string ToString()Public Function ToString() As string

    Returns

    • string
      string
      string
      string

      A string that represents the current object.

  • TryAppendWithoutValidation(System.String,System.String)
    TryAppendWithoutValidation(System.String,System.String)
    TryAppendWithoutValidation(System.String,System.String)
    TryAppendWithoutValidation(System.String,System.String)

    Try to append the specified item to the HttpRequestHeaderCollection without validation.

    public bool TryAppendWithoutValidation(System.String,System.String)public bool TryAppendWithoutValidation(System.String,System.String)Public Function TryAppendWithoutValidation(System.String,System.String) As bool

    Parameters

    • name
      System.String
      System.String
      System.String
      System.String

      The name of the item to append.

    • value
      System.String
      System.String
      System.String
      System.String

      The value of the item to append.

    Returns

    • bool
      bool
      bool
      bool

      true if the item was appended; otherwise false.

    Remarks

    The TryAppendWithoutValidation(System.String,System.String) method is available when you need to work with an HTTP header on an HTTP request that doesn't have a strongly-typed class for the HTTP header. If there is a strongly-typed implementation of the HTTP header, then the methods and properties on the strongly-typed class should be used instead of the TryAppendWithoutValidation(System.String,System.String) method.

Device family

Windows 10 (introduced v10.0.10240.0)

API contract

Windows.Foundation.UniversalApiContract (introduced v1)

Attributes

Windows.Foundation.Metadata.ThreadingAttribute
Windows.Foundation.Metadata.MarshalingBehaviorAttribute
Windows.Foundation.Metadata.ContractVersionAttribute
Windows.Foundation.Metadata.DualApiPartitionAttribute

Details

Assembly

Windows.Web.Http.Headers.dll