Serializing Request.Form to a Dictionary or something

Question

Hi i need to pass my Request.Form as a parameter, but first i have to add some key/value pairs to it. I get the exception that the Collection is readonly.

I've tried:

System.Collections.Specialized.NameValueCollection myform = Request.Form; 

and i get the same error.

and i've tried:

foreach(KeyValuePair<string, string> pair in Request.Form)
{
     Response.Write(Convert.ToString(pair.Key) + " - " + Convert.ToString(pair.Value) + "<br />");
}

to test if i can pass it one by one to another dictionary, but i get:

System.InvalidCastException: Specified cast is not valid.

some help, anyone? Thanx

Answer 1

You don't need to cast a string to string. NameValueCollection is built around string keys, and string values. How about a quick extension method:

public static IDictionary<string, string> ToDictionary(this NameValueCollection col)
{
  var dict = new Dictionary<string, string>();

  foreach (var key in col.Keys)
  {
    dict.Add(key, col[key]);
  }

  return dict;
}

That way you can easily go:

var dict = Request.Form.ToDictionary();
dict.Add("key", "value");

Answer 2

If your already using MVC then you can do it with 0 lines of code.

using System.Web.Mvc;

var dictionary = new Dictionary<string, object>();
Request.Form.CopyTo(dictionary);

Answer 3

Andre,

how about:

System.Collections.Specialized.NameValueCollection myform = Request.Form; 

IDictionary<string, string> myDictionary = 
    myform.Cast<string>()
           .Select(s => new { Key = s, Value = myform[s] })
           .ToDictionary(p => p.Key, p => p.Value);

uses LINQ to keep it all on one 'line'. this could be exrapolated to an extension method of:

public static IDictionary<string, string> ToDictionary(this NameValueCollection col)
{
    IDictionary<string, string> myDictionary = new Dictionary<string, string>();
    if (col != null)
    {
        myDictionary =
            col.Cast<string>()
                .Select(s => new { Key = s, Value = col[s] })
                .ToDictionary(p => p.Key, p => p.Value);
    }
    return myDictionary;
}

hope this helps..

Answer 4

public static IEnumerable<Tuple<string, string>> ToEnumerable(this NameValueCollection collection)
{
    return collection
      //.Keys
        .Cast<string>()
        .Select(key => new Tuple<string, string>(key, collection[key]));
}

or

public static Dictionary<string, string> ToDictionary(this NameValueCollection collection)
{
    return collection
      //.Keys
        .Cast<string>()
        .ToDictionary(key => key, key => collection[key]));
}