How can I add additional Dictionary object

Question

How Can I Add additional Dictionary Object below

var topLevel1 = resultRows.GroupBy(g => g["CustomerAccountType"])
.ToDictionary(g => g.Key, g => g.ToList());

I want to add this within the LINQ line

  new Dictionary<string, object> { {"children", someDictionaryAgain}}

I want to append additional dictionary object after the .ToDictionary()

something like

var topLevel1 = resultRows.GroupBy(g => g["CustomerAccountType"])
.ToDictionary(g => g.Key, g => g.ToList()).Add(new Dictionary<string, object> {     {"somekey", "somevalueorobject"}}

Here is the expected output I wanted.

var toplevel = Dictionary <stirng, object> {
  {"Actual1", 0},
  {"Actual2", 0}
 }

After .ToDictionary() --> What code is best to use to achieve

    var toplevel = Dictionary <stirng, object> {
      {"Actual1", 0},
     {"Actual2", 0},
     {"AddedDynamically",0}
 }

You want to make another new dictionary? How would that even work? I'm pretty sure I know what the answer is (that you can't) but would like to understand better what you are trying to do. — BradleyDotNET, Dec 22 '14 at 18:13
I wanted to append additional Dictionary entry from the list dynamically — agentpx, Dec 22 '14 at 18:18
Nope just one, I'd like to add a custom dictionary value to the end of the ToDictionary Object created. — agentpx, Dec 22 '14 at 18:20

David · Accepted Answer · 2014-12-22T20:36:39.380

3

ToDictionary outputs a Dictionary, so you can easily save the result into a variable and add to it. To ensure you're getting a string and object dictionary, though, you'll need to explicitly reference the types.

var topLevel1 = resultRows
    .GroupBy(g => g["CustomerAccountType"])
    .ToDictionary(
        g => g.Key,                                // This is fine since it returns a string
        g => { return g.ToList() as object; });    // Explicitlyreturn this as an object
topLevel1.Add("somekey", "somevalueorobject");

To expand nested collections, use SelectMany instead of Select

var topLevel1 = resultRows
    .GroupBy(g => g["CustomerAccountType"])
    .SelectMany(g => g.Select(v => new { Key = g.Key, Value = v })) // This creates an anonymous type for use further into the query
    .ToDictionary(
        g => g.Key,
        g => g.Value);

edited Dec 22 '14 at 20:36

answered Dec 22 '14 at 18:22

David

10,458
1
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Looks close, but can we do that in one line? i need lambda because the additional "somekey" will be children of the first dictionary. – agentpx Dec 22 '14 at 18:28
The doing of this in one line for children of each dictionary? `.SelectMany` - I'll update my answer accordingly – David Dec 22 '14 at 20:22
Nope I will take care of the children object "somevalueObject" I just need to make your sample one LINQ syntax one liner. Not after the fact of creating topLevel1. I'll wait for your update. Thanks. – agentpx Dec 22 '14 at 20:27

score 2 · Answer 2 · edited May 23 '17 at 11:57

You can't do this, for multiple reasons.

Primarily, because ToDictionary returns a new dictionary object (which you then assign). Calling Add on this returns void, so you can't do the assignment.

Basically, you have to leave your first line alone. To do the merge, you need to do a foreach. This part of the question has been discussed before at: Merging dictionaries in C#

Basically you end up with a loop:

foreach (KeyValuePair<string, object> kvp in secondDictionary)
    topLevel1.Add(kvp.Key, kvp.Value);

Note that the code above will break on a duplicate key.

niceman · Answer 3 · 2014-12-22T19:10:27.500

1

you can try something like this:

var topLevel1 = resultRows
.GroupBy(g => g["CustomerAccountType"])
.ToDictionary(
    g => g.Key,                                
    g => { return g.ToList() as object; }).Union(new Dictionary<string, object> {     {"somekey", "somevalueorobject"}).ToDictionary(x=>x.Key,x=>x.Value);

edited Dec 22 '14 at 19:10

answered Dec 22 '14 at 18:43

niceman

2,653
29
57

this will not add duplicate entries since union means all shared and non-shared elements just once. – niceman Dec 22 '14 at 18:45

score 0 · Answer 4 · answered Dec 22 '14 at 18:19

0

If you use something like:

Dictionary<string,Dictionary<string,object>>

then you have the dictionary you are looking for ...

answered Dec 22 '14 at 18:19

Anders H

391
4
11

score 0 · Answer 5 · answered Dec 22 '14 at 18:24

public class Test
{
    public static void test()
    {
        Dictionary<string, int> d1 = new Dictionary<string, int>();
        Dictionary<string, int> d2 = new Dictionary<string, int>();

        d1.AddRange(d2);
    }
}

public static class Extensions
{
    public static Dictionary<K, V> AddRange<K, V>(this Dictionary<K, V> d1, Dictionary<K, V> d2)
    {
        foreach (var kv in d2)
        {
            d1[kv.Key] = kv.Value;
        }
        return d1;
    }
}

Using this extension function will:

not fail upon duplicate key
return the starting dictionary so you have a fluent interface

how will test method work while not providing the parameters to merge ? — niceman, Dec 22 '14 at 18:45

How can I add additional Dictionary object

5 Answers5