CODEWITHSUNDEEP
c#dictionary
Ben R
Ben R

Reputation: 85

How do i extract from a nested dictionary?

I have created a nested dictionary with the following:

Dictionary<DateTime, Dictionary<string, string>> dateDict =
    new Dictionary<DateTime, Dictionary<string, string>>();

I then enter values to this dictionary using the following:

while (reader.Read())
{
    DateTime date = DateTime.Parse(reader["Event_Date"].ToString());
    string name = reader["Event_Name"].ToString();
    string guid = reader["Event_GUID"].ToString();
    dateDict.Add(date, new Dictionary<string, string>());
    dateDict[date].Add(name, guid);
}

My question is how do I correctly pull the variables back out from the nested dictionary?

I have this loop running to pull values out and assign them to DateTimePickers and TextFields:

for (int i = 0; i < dateDict.Count; i++)
{
    DateTime keyVar = dateDict.ElementAt(i).Key;
    eventDateBoxes[i].Value = keyVar;
    eventTextBoxes[i].Text = dateDict[keyVar[]];
}

The eventTextBoxes part is where im getting stuck on how to pull the value from the nested dictionary, hence why that part of the code is wrong/incomplete.

I can't use tuples as I am using .NET lower than 4 and can't seem to wrap my head around making a custom class to act as its own tuple or multidictionary.

Upvotes: 0

Views: 945

Answers (3)

Matt Burland
Matt Burland

Reputation: 45145

It sounds like you don't need a Dictionary<DateTime, Dictionary<string, string>> since you have only one item inside your inner dictionary, you need a Dictionary<DateTime, Dictionary<string, Event>> where Event is a class that holds you event data. Something like:

public class Event
{
    public string Name {get; set;}
    public string Guid {get; set;}  // you could actually use the GUID type here!
}

Then you'd populate it like:

while (reader.Read())
{
    DateTime date = DateTime.Parse(reader["Event_Date"].ToString());
    string name = reader["Event_Name"].ToString();
    string guid = reader["Event_GUID"].ToString();
    dateDict.Add(date, new Event() { Name = name, Guid = guid };
}

Then when you get an item from your dictionary by key:

var item = dateDict[someKey];

You can get your name and guid back:

var name = item.Name;
var guid = item.guid;

Additionally, since you are iterating through your dictionary by numerical index rather than by key, it seems likely that you probably don't need a dictionary at all. Maybe all you need to do is add a Date property to your Event and just have an List<Event>.

Upvotes: 1

500 - Internal Server Error
500 - Internal Server Error

Reputation: 28839

This is the basic outline of what you would do:

foreach (var element in dateDict)
{
    eventDateBoxes[i].Value = element.Key;
    foreach (var subElement in element.Value)
    {
        eventTextBoxes[i].Text = subElement.Value;
    }
}

As others point out in the comment, there can be no one-to-one relationship between the elements in the outer dictionary and the text boxes as there can (potentially) be multiple entries in the sub-element.

Upvotes: 1

Tim Schmelter
Tim Schmelter

Reputation: 460158

I would use a foreach or a LINQ query. But it's not clear what you want as DateTimePicker.Text:

List<DateTimePicker> eventDateBoxes = dateDict
    .Select(kv => new{ 
       Date = kv.Key, 
       EventName = kv.Value["Event_Name"],
       EventGuid = kv.Value["Event_GUID"],
    })
    .Select(x => new DateTimePicker{ Value = x.Date, Text = x.EventName })
    .ToList();

Upvotes: 1

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