Asp.net request.UrlReferrer is null

in my web appl开发者_如何学Pythonication Request.UrlReferrer is null. how can i set UrlReferrer ?

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You don't need to set the UrlReferrer. The referrrer is something that the browser sends to the server. This property is how you read what the browser sent as a referrer. For obvious reasons you cannot set what the browser sends you because your server does not control it.

Why do you want to set it anyway?

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you want to make sure UrlReferrer is not null. if you do not it can create 'Object reference not set to an instance of an object.' error.

if (!(Request.UrlReferrer == null)) {
    'if Request.UrlReferrer is not null do this 
}
else {
    'set Request.UrlReferrer to null
}