如何从任何地方访问 Request.QueryString？

Question

I've gotten an error with the Request.QueryString and I cant seem to find any solution..

 public static DataTable SelectFrom(string Table, string Felt, string query)
  {
    DataTable dt = new DataTable();
    try
    {

        SqlCommand cmd = new SqlCommand("SELECT * FROM " + Table + " WHERE " + Felt + " = @parameter", conn);
        cmd.Parameters.AddWithValue("@parameter", Request.QueryString[query]);

        SqlDataAdapter ad = new SqlDataAdapter(cmd);
        ad.Fill(dt);
    }
    catch
    {

    }
    return dt;
}

Answer 1

似乎您的代码在单独的类或程序集中（不在页面类中），如果是，请使用

httpcontext.current.request.QueryString

Answer 2

You are trying to get QueryString inside static method and there is no Request object inside this method so you need to use.

HttpContext.Current.Request.QueryString 

in static method.

Answer 3

Let us know the error that you got.

Always before using Request.QueryString you need to check it for null, like

if(Request.QueryString[query] != null && Request.QueryString[query].ToString() != string.empty)