Question

我们假设一个aspx页面有多个查询字符串，例如books.aspx?author=Arthor&level=4&year=2004。

我想创建一个清除特定查询字符串的按钮。

例如，点击clearAuthorBtn时，应将用户重定向到books.aspx?level=4&year=2004

我该怎么做？非常感谢你。

Answer 1

ASP.NET，C＃这样的伪代码应该在你的按钮事件处理程序中起作用：

  foreach (var key in Request.QueryString)
  {
    string url = "books.aspx?";
    if (key != "author")
    {
      url = url + Server.UrlEncode(key) + "=" + Server.UrlEncode(Request.QueryString[key]) + "&";
    }
    Response.Redirect(url);
  }

Answer 2

这是一种可能有用的方法。我没有测试过这个特定的实现，但类似的东西应该足够了（并且相当健壮）。

public static string GetQueryStringWithoutKey(HttpRequest request, string keyToRemove) {

    // Assert keyToRemove is not null.
    if (keyToRemove == null) {
        throw new ArgumentNullException("keyToRemove");
    }

    // If the QueryString has no data, simply return an empty string.
    if (request.QueryString.AllKeys.Length == 0) {
        return string.Empty;
    }

    // Reconstruct the QueryString with everything except the existing key/value pair.
    StringBuilder queryStringWithoutKey = new StringBuilder();
    for (int i = 0; i < request.QueryString.AllKeys.Length; i++) {

        // Only append data that is not the given key/value pair.
        if (request.QueryString.AllKeys[i] != null &&
            request.QueryString.AllKeys[i].ToLower() != keyToRemove.ToLower()) {
            queryStringWithoutKey.Append(request.QueryString.AllKeys[i]);
            queryStringWithoutKey.Append("=");
            queryStringWithoutKey.Append(request.QueryString[i]);
            queryStringWithoutKey.Append("&");
        }
    }

    // We might have had a key, but if the only key was Message, then there is no
    // data to return for the QueryString.
    if (queryStringWithoutKey.Length == 0) {
        return string.Empty;
    }

    // Remove trailing ampersand.
    return queryStringWithoutKey.ToString().TrimEnd('&');
}

你可以像这样调用上面的方法（注意我使用HttpContext.Current，以防你想在Page或UserControl之外调用它）：

HttpRequest request = HttpContext.Current.Request;
string url = request.ServerVariables["PATH_INFO"];
string queryString = GetQueryStringWithoutKey(request, "author");
if (!string.IsNullOrEmpty(queryString) {
    url += "?" + queryString;
}
HttpContext.Current.Response.Redirect(url);

删除特定的QueryStrings

2 个答案: