当从代码中调用web资源时，一个常见的任务是构建一个包含所有必要参数的查询字符串。虽然这绝不是火箭科学，但有一些漂亮的细节需要注意，例如，如果不是第一个参数，则添加&，对参数进行编码等。
实现它的代码非常简单，但有点乏味:
StringBuilder SB = new StringBuilder();
if (NeedsToAddParameter A)
{
SB.Append("A="); SB.Append(HttpUtility.UrlEncode("TheValueOfA"));
}
if (NeedsToAddParameter B)
{
if (SB.Length>0) SB.Append("&");
SB.Append("B="); SB.Append(HttpUtility.UrlEncode("TheValueOfB")); }
}
这是一个非常常见的任务，人们希望存在一个实用工具类，使其更加优雅和可读。扫描MSDN，我没有找到一个，这让我想到了以下问题:
你所知道的最优雅干净的方法是什么?
当前回答
查询字符串可以通过以下方式添加到URL:
创建名称值集合对象 将查询字符串项及其值添加到此对象 将此名称值集合对象编码为下面链接中提供的代码的url
https://blog.codingnovice.com/blog
public ActionResult Create()
{
//declaring name value collection object
NameValueCollection collection = new NameValueCollection();
//adding new value to the name value collection object
collection.Add("Id1", "wwe323");
collection.Add("Id2", "454w");
collection.Add("Id3", "tyt5656");
collection.Add("Id4", "343wdsd");
//generating query string
string url = GenerateQueryString(collection);
return View();
}
private string GenerateQueryString(NameValueCollection collection)
{
var querystring = (
from key in collection.AllKeys
from value in collection.GetValues(key)
select string.Format("{0}={1}",
HttpUtility.UrlEncode(key),
HttpUtility.UrlEncode(value))
).ToArray();
return "?" + string.Join("&", querystring);
}
其他回答
另一种方法是创建一个类NameValueCollection的扩展，返回完整的Url:
public static class CustomMethods
{
public static string ToUrl(this System.Collections.Specialized.NameValueCollection collection)
{
if (collection.Count == 0) return "";
string completeUrl = "?";
for (int i = 0; i < collection.Count; i++)
{
completeUrl += new Page().Server.UrlEncode(collection.GetKey(i)) + "=" + new Page().Server.UrlEncode(collection.Get(i));
if ((i + 1) < collection.Count) completeUrl += "&";
}
return completeUrl;
}
}
然后，你可以使用你的新方法，例如:
System.Collections.Specialized.NameValueCollection qString = new System.Collections.Specialized.NameValueCollection();
qString.Add("name", "MyName");
qString.Add("email", "myemail@test.com");
qString.ToUrl(); //Result: "?name=MyName&email=myemail%40test.com"
虽然不够优雅，但我选择了一个更简单的版本，它不使用NameValueCollecitons——只是一个包装在StringBuilder周围的构建器模式。
public class UrlBuilder
{
#region Variables / Properties
private readonly StringBuilder _builder;
#endregion Variables / Properties
#region Constructor
public UrlBuilder(string urlBase)
{
_builder = new StringBuilder(urlBase);
}
#endregion Constructor
#region Methods
public UrlBuilder AppendParameter(string paramName, string value)
{
if (_builder.ToString().Contains("?"))
_builder.Append("&");
else
_builder.Append("?");
_builder.Append(HttpUtility.UrlEncode(paramName));
_builder.Append("=");
_builder.Append(HttpUtility.UrlEncode(value));
return this;
}
public override string ToString()
{
return _builder.ToString();
}
#endregion Methods
}
根据现有的答案，我确保使用HttpUtility。UrlEncode调用。它是这样使用的:
string url = new UrlBuilder("http://www.somedomain.com/")
.AppendParameter("a", "true")
.AppendParameter("b", "muffin")
.AppendParameter("c", "muffin button")
.ToString();
// Result: http://www.somedomain.com?a=true&b=muffin&c=muffin%20button
未经测试，但我认为沿着这些路线的东西会工作得很好
public class QueryString
{
private Dictionary<string,string> _Params = new Dictionary<string,string>();
public overide ToString()
{
List<string> returnParams = new List<string>();
foreach (KeyValuePair param in _Params)
{
returnParams.Add(String.Format("{0}={1}", param.Key, param.Value));
}
// return String.Format("?{0}", String.Join("&", returnParams.ToArray()));
// credit annakata
return "?" + String.Join("&", returnParams.ToArray());
}
public void Add(string key, string value)
{
_Params.Add(key, HttpUtility.UrlEncode(value));
}
}
QueryString query = new QueryString();
query.Add("param1", "value1");
query.Add("param2", "value2");
return query.ToString();
我为我的剃刀项目写了一个助手，使用了其他答案的一些提示。
ParseQueryString业务是必要的，因为我们不允许篡改当前请求的QueryString对象。
@helper GetQueryStringWithValue(string key, string value) {
var queryString = System.Web.HttpUtility.ParseQueryString(HttpContext.Current.Request.QueryString.ToString());
queryString[key] = value;
@Html.Raw(queryString.ToString())
}
我是这样使用的:
location.search = '?@Helpers.GetQueryStringWithValue("var-name", "var-value")';
如果希望它接受多个值，只需将参数更改为Dictionary，并将对添加到查询字符串中。
只针对那些需要VB的人。NET版本的顶级答案:
Public Function ToQueryString(nvc As System.Collections.Specialized.NameValueCollection) As String
Dim array As String() = nvc.AllKeys.SelectMany(Function(key As String) nvc.GetValues(key), Function(key As String, value As String) String.Format("{0}={1}", System.Web.HttpUtility.UrlEncode(key), System.Web.HttpUtility.UrlEncode(value))).ToArray()
Return "?" + String.Join("&", array)
End Function
以及没有LINQ的版本:
Public Function ToQueryString(nvc As System.Collections.Specialized.NameValueCollection) As String
Dim lsParams As New List(Of String)()
For Each strKey As String In nvc.AllKeys
Dim astrValue As String() = nvc.GetValues(strKey)
For Each strValue As String In astrValue
lsParams.Add(String.Format("{0}={1}", System.Web.HttpUtility.UrlEncode(strKey), System.Web.HttpUtility.UrlEncode(strValue)))
Next ' Next strValue
Next ' strKey
Dim astrParams As String() = lsParams.ToArray()
lsParams.Clear()
lsParams = Nothing
Return "?" + String.Join("&", astrParams)
End Function ' ToQueryString
和没有LINQ的c#版本:
public static string ToQueryString(System.Collections.Specialized.NameValueCollection nvc)
{
List<string> lsParams = new List<string>();
foreach (string strKey in nvc.AllKeys)
{
string[] astrValue = nvc.GetValues(strKey);
foreach (string strValue in astrValue)
{
lsParams.Add(string.Format("{0}={1}", System.Web.HttpUtility.UrlEncode(strKey), System.Web.HttpUtility.UrlEncode(strValue)));
} // Next strValue
} // Next strKey
string[] astrParams =lsParams.ToArray();
lsParams.Clear();
lsParams = null;
return "?" + string.Join("&", astrParams);
} // End Function ToQueryString
