Sometimes we have to operate a URL address query parameters, in order not to break the original structure of the URL, we generally can not directly in the back of the URL plus &query=value, especially in our URL has more than one parameter, this kind of handling more trouble.
The following two small methods are specifically used to add a query parameter to a URL or delete a query parameter, the two methods hide the original URL has no parameters, is not originally have this parameter, there is no fragment (#anchor) these details and processing
/**////<summary>
Add a query to a URL.
If the URL has not any query,then append the query key and value to it.
If the URL has some queries, then check it if exists the query key already,replace the value, or append the key and VA Lue
If the URL has any fragment, append fragments to the URL end.
</summary>
public static string Safeaddquerytourl (string key,string value,string URL)
{
int fragpos = URL. LastIndexOf ("#");
string fragment = String. Empty;
if (Fragpos >-1)
{
fragment = URL. Substring (Fragpos);
url = URL. Substring (0,fragpos);
}
int querystart = URL. IndexOf ("?");
if (Querystart < 0)
{
url = "?" +key+ "=" +value;
}
Else
{
Regex reg = new Regex (@ <=[&\?]) +key+@ "=[^\s&#]*", regexoptions.compiled);
if (Reg. IsMatch (URL))
url = Reg. Replace (url,key+ "=" +value);
Else
URL + "&" +key+ "=" +value;
}
return url+fragment;
}
/**////<summary>
Remove a query from URL
</summary>
<param name= "Key" ></param>
<param name= "url" ></param>
<returns></returns>
public static string Saferemovequeryfromurl (String key,string URL)
{
Regex reg = new Regex (@ "[&\?]" +key+@ "=[^\s&#]*&?", regexoptions.compiled);
Return Reg. Replace (url,new matchevaluator (Putawaygarbagefromurl));
}
private static string Putawaygarbagefromurl (match match)
{
String value = Match. Value;
if (value. EndsWith ("&"))
return value. Substring (0,1);
Else
return string. Empty;
}
Test:
string s = "Http://www.cnblogs.com/?a=1&b=2&c=3#tag";
WL (Saferemovequeryfromurl ("a", s));
WL (Saferemovequeryfromurl ("B", s));
WL (Saferemovequeryfromurl ("C", s));
WL (Safeaddquerytourl ("D", "new", s));
WL (Safeaddquerytourl ("A", "newvalue", s));
The output is as follows:
Http://www.cnblogs.com/?b=2&c=3#tag
Http://www.cnblogs.com/?a=1&c=3#tag
Http://www.cnblogs.com/?a=1&b=2#tag
Http://www.cnblogs.com/?a=1&b=2&c=3&d=new#tag
Http://www.cnblogs.com/?a=newvalue&b=2&c=3#tag
