问题
Request["key"] vs Request.Params["key"] vs Request.QueryString["key"]
Which method do you seasoned programmers use? and why?
回答1:
I recommend Request.QueryString["key"]. There isn't a lot of difference to Request["Key"] for a query string but there is a big(er) difference if you are trying to get the value from ServerVariables. Request["Key"] looks for a value in QueryString if null, it looks at Form, then Cookie and finally ServerVariables.
Using Params is the most costly. The first request to params creates a new NameValueCollection and adds each of the QueryString, Form, Cookie and ServerVariables to this collection. For the second request on it is more performant than Request["Key"].
Having said that the performance difference for a couple of keys is fairly negligable. The key here is code should show intent and using Request.QueryString makes it clear what your intent is.
回答2:
I prefer to use Request.QueryString["key"] because it helps the code-reader know exactly where you are getting the data from. I tend not to use Request.Params["key"] because it could refer to a cookie, query string and a few other things; so the user has to think a little. The less time someone needs to figure out what you are thinking, the easier it is to maintain the code.
回答3:
HttpRequest.Params or Request.Params gets just about everything (querystring, form, cookie and session variables) from the httprequest, whereas Request.Querystring only will pull the querystring... all depends on what you are doing at the time.
回答4:
I always explicitly specify the collection. If for some reason you want to allow overrides, code the "get" for each one and write some clear code that shows your hierarchy for choosing one over the other. IMO, I dislike getting a value from multiple sources without a clear business reason for so doing.
回答5:
As a kindly notice, If you set requestValidationMode="4.5" under web.config, both Request.QueryString[“key”] and Request[“key”] will use "lazy loading" behavior as design.
However, somehow Request.Params[“key”] will still trigger validation as the behavior of 4.0 .
This odd behavior really confuses me for a long time.
来源：https://stackoverflow.com/questions/2312855/requestkey-vs-request-paramskey-vs-request-querystringkey