IDictionary<string, object> to ExpandoObject extension method

Yan Cui

I help clients go faster for less using serverless technologies.

As you know, the ExpandoObject class implements the IDictionary<string, object> interface, so if you have an ExpandoObject you can easily cast it to an IDictionary<string, object> but there’s no built-in way to easily do the reverse.

Luckily, I came across a very useful extension method today which converts an IDictionary<string, object> into an ExpandoObject, which you can then use dynamically in your code, sweet! :-)

With some small modifications, here’s the code I ended up with, with some comments thrown in for good measures:

   1: /// <summary>

   2: /// Extension method that turns a dictionary of string and object to an ExpandoObject

   3: /// </summary>

   4: public static ExpandoObject ToExpando(this IDictionary<string, object> dictionary)

   5: {

   6:     var expando = new ExpandoObject();

   7:     var expandoDic = (IDictionary<string, object>)expando;


   9:     // go through the items in the dictionary and copy over the key value pairs)

  10:     foreach (var kvp in dictionary)

  11:     {

  12:         // if the value can also be turned into an ExpandoObject, then do it!

  13:         if (kvp.Value is IDictionary<string, object>)

  14:         {

  15:             var expandoValue = ((IDictionary<string, object>)kvp.Value).ToExpando();

  16:             expandoDic.Add(kvp.Key, expandoValue);

  17:         }

  18:         else if (kvp.Value is ICollection)

  19:         {

  20:             // iterate through the collection and convert any strin-object dictionaries

  21:             // along the way into expando objects

  22:             var itemList = new List<object>();

  23:             foreach (var item in (ICollection)kvp.Value)

  24:             {

  25:                 if (item is IDictionary<string, object>)

  26:                 {

  27:                     var expandoItem = ((IDictionary<string, object>) item).ToExpando();

  28:                     itemList.Add(expandoItem);

  29:                 }

  30:                 else

  31:                 {

  32:                     itemList.Add(item);

  33:                 }

  34:             }


  36:             expandoDic.Add(kvp.Key, itemList);

  37:         }

  38:         else

  39:         {

  40:             expandoDic.Add(kvp);

  41:         }

  42:     }


  44:     return expando;

  45: }


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10 thoughts on “IDictionary<string, object> to ExpandoObject extension method”

  1. Pingback: Getting dynamic ExpandoObject to serialize to JSON as expected | PatridgeDev

  2. Pingback: IDictionary to ExpandoObject extension method | - wxy

  3. “ToExpando()” is what we’re defining here, as an extension method to IDictionary.

    We also call it recursively in the body of this extension method, so you won’t find it (or need it) on ICollection class, does this make sense?

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