HttpResponse.AppendHeader Method (String, String)


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Adds an HTTP header to the output stream.

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

Public Sub AppendHeader (
	name As String,
	value As String


Type: System.String

The name of the HTTP header to add to the output stream.

Type: System.String

The string to append to the header.

Exception Condition

The header is appended after the HTTP headers have been sent.

If you use the AppendHeader method to send cache-specific headers and at the same time use the cache object model (Cache) to set cache policy, HTTP response headers that pertain to caching (Cache-Control, Expires, Last-Modified, Pragma, and Vary) might be deleted when the cache object model is used. This behavior enables ASP.NET to maintain the most restrictive settings. For example, consider a page that includes user controls. If those controls have conflicting cache policies, the most restrictive cache policy will be used. If one user control sets the header "Cache-Control: Public" and another user control sets the more restrictive header "Cache-Control: Private" via calls to SetCacheability, then the "Cache-Control: Private" header will be sent with the response.

For a list of standard HTTP/1.1 headers, see section 14, "Header Field Definitions," in the Hypertext Transfer Protocol -- HTTP/1.1 specification on the World Wide Web Consortium (W3C) Web site.

The following example calls the AppendHeader method to add a custom header to the HttpResponse object sent to the requesting client.

Response.AppendHeader("CustomAspNetHeader", "Value1")

.NET Framework
Available since 1.1
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