We Keep Coding

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.

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>.

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();

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.

Updating entire node with mutating cypher in Neo4jclient

I need to update all the properties of a given node, using mutating cypher. I want to move away from Node and NodeReference because I understand they are deprecated, so can't use IGraphClient.Update. I'm very new to mutating cypher. I'm writing in C#, using Neo4jclient as the interface to Neo4j.
I did the following code which updates the "Name" property of a "resunit" where property "UniqueId" equals 2. This works fine. However,
* my resunit object has many properties
* I don't know which properties have changed
* I'm trying to write code that will work with different types of objects (with different properties)
It was possible with IGraphClient.Update to pass in an entire object and it would take care of creating cypher that sets all properies.
Can I somehow pass in my object with mutating cypher as well?
The only alternative I can see is to reflect over the object to find all properties and generate .Set for each, which I'd like to avoid. Please tell me if I'm on the wrong track here.
string newName = "A welcoming home";
var query2 = agencyDataAccessor
.GetAgencyByKey(requestingUser.AgencyKey)
.Match("(agency)-[:HAS_RESUNIT_NODE]->(categoryResUnitNode)-[:THE_UNIT_NODE]->(resunit)")
.Where("resunit.UniqueId = {uniqueId}")
.WithParams(new { uniqueId = 2 })
.With("resunit")
.Set("resunit.Name = {residentialUnitName}")
.WithParams(new { residentialUnitName = newName });
query2.ExecuteWithoutResults();

It is indeed possible to pass an entire object! Below I have an object called Thing defined as such:
public class Thing
{
public int Id { get; set; }
public string Value { get; set; }
public DateTimeOffset Date { get; set; }
public int AnInt { get; set; }
}
Then the following code creates a new Thing and inserts it into the DB, then get's it back and updates it just by using one Set command:
Thing thing = new Thing{AnInt = 12, Date = new DateTimeOffset(DateTime.Now), Value = "Foo", Id = 1};
gc.Cypher
.Create("(n:Test {thingParam})")
.WithParam("thingParam", thing)
.ExecuteWithoutResults();
var thingRes = gc.Cypher.Match("(n:Test)").Where((Thing n) => n.Id == 1).Return(n => n.As<Thing>()).Results.Single();
Console.WriteLine("Found: {0},{1},{2},{3}", thingRes.Id, thingRes.Value, thingRes.AnInt, thingRes.Date);
thingRes.AnInt += 100;
thingRes.Value = "Bar";
thingRes.Date = thingRes.Date.AddMonths(1);
gc.Cypher
.Match("(n:Test)")
.Where((Thing n) => n.Id == 1)
.Set("n = {thingParam}")
.WithParam("thingParam", thingRes)
.ExecuteWithoutResults();
var thingRes2 = gc.Cypher.Match("(n:Test)").Where((Thing n) => n.Id == 1).Return(n => n.As<Thing>()).Results.Single();
Console.WriteLine("Found: {0},{1},{2},{3}", thingRes2.Id, thingRes2.Value, thingRes2.AnInt, thingRes2.Date);
Which gives:
Found: 1,Foo,12,2014-03-27 15:37:49 +00:00
Found: 1,Bar,112,2014-04-27 15:37:49 +00:00
All properties nicely updated!

Map enum value robustly

I have a form where I collect data from users. When this data is collected, I pass it to various partners, however each partner has their own rules for each piece of data, so this has to be converted. I can make this happen, but my worries are about the robustness. Here's some code:
First, I have an enum. This is mapped to dropdown a dropdown list - the description is the text value, and the int mapped to the value.
public enum EmploymentStatusType
{
[Description("INVALID!")]
None = 0,
[Description("Permanent full-time")]
FullTime = 1,
[Description("Permanent part-time")]
PartTime = 2,
[Description("Self employed")]
SelfEmployed = 3
}
When the form is submitted, the selected value is converted to its proper type and stored in another class - the property looks like this:
protected virtual EmploymentStatusType EmploymentStatus
{
get { return _application.EmploymentStatus; }
}
For the final bit of the jigsaw, I convert the value to the partners required string value:
Dictionary<EmploymentStatusType, string> _employmentStatusTypes;
Dictionary<EmploymentStatusType, string> EmploymentStatusTypes
{
get
{
if (_employmentStatusTypes.IsNull())
{
_employmentStatusTypes = new Dictionary<EmploymentStatusType, string>()
{
{ EmploymentStatusType.FullTime, "Full Time" },
{ EmploymentStatusType.PartTime, "Part Time" },
{ EmploymentStatusType.SelfEmployed, "Self Employed" }
};
}
return _employmentStatusTypes;
}
}
string PartnerEmploymentStatus
{
get { return _employmentStatusTypes.GetValue(EmploymentStatus); }
}
I call PartnerEmploymentStatus, which then returns the final output string.
Any ideas how this can be made more robust?

Then you need to refactor it into one translation area. Could be something like a visitor pattern implementation. Your choices are distribute the code (as you are doing now) or visitor which would centralize it. You need to build in a degree of fragility so your covering tests will show problems when you extend in order to force you to maintain the code properly. You are in a fairly common quandry which is really a code organisational one

I did encounter such a problem in one of my projects and I solved it by using a helper function and conventions for resource names.
The function is this one:
public static Dictionary<T, string> GetEnumNamesFromResources<T>(ResourceManager resourceManager, params T[] excludedItems)
{
Contract.Requires(resourceManager != null, "resourceManager is null.");
var dictionary =
resourceManager.GetResourceSet(culture: CultureInfo.CurrentUICulture, createIfNotExists: true, tryParents: true)
.Cast<DictionaryEntry>()
.Join(Enum.GetValues(typeof(T)).Cast<T>().Except(excludedItems),
de => de.Key.ToString(),
v => v.ToString(),
(de, v) => new
{
DictionaryEntry = de,
EnumValue = v
})
.OrderBy(x => x.EnumValue)
.ToDictionary(x => x.EnumValue, x => x.DictionaryEntry.Value.ToString());
return dictionary;
}
The convention is that in my resource file I will have properties that are the same as enum values (in your case None, PartTime etc). This is needed to perform the Join in the helper function which, you can adjust to match your needs.
So, whenever I want a (localized) string description of an enum value I just call:
var dictionary = EnumUtils.GetEnumNamesFromResources<EmploymentStatusType>(ResourceFile.ResourceManager);
var value = dictionary[EmploymentStatusType.Full];

Using Contains() list method to evaluate list contents

I have a list that contains 3 items, two of type_1, and one of type_2. I want to return a second list that contains the type and number of that type that exists. When stepping through the breakpoints set at the foreach loop, the IF statement is never true. I assume there is something wrong with my attempt to use Contains() method.
The output should be something like:
type_1 2
type_2 1
Instead, it evaluates as:
type_1 1
type_1 1
type_2 1
Is my use of Contains() not correct?
public List<item_count> QueryGraphListingsNewAccountReport()
List<item> result = new List<items>();
var type_item1 = new item { account_type = "Type_1" };
var type_item2 = new item { account_type = "Type_1" };
var type_item3 = new item { account_type = "Type_2" };
result.Add(type_item1);
result.Add(type_item2);
result.Add(type_item3);
//Create a empty list that will hold the account_type AND a count of how many of that type exists:
List<item_count> result_count = new List<item_count>();
foreach (var item in result)
{
if (result_count.Contains(new item_count { account_type = item.account_type, count = 1 } ) == true)
{
var result_item = result_count.Find(x => x.account_type == item.account_type);
result_item.count += 1;
result_count.Add(result_item);
}
else
{
var result_item = new item_count { account_type = item.account_type, count = 1 };
result_count.Add(result_item);
}
}
return result_count;
}
public class item
{
public string account_type { get; set; }
}
public class item_count
{
public int count {get; set;}
public string account_type { get; set; }
}

I think your problem is that you don't want to use contains at all. You are creating a new object in your contains statement and, obviously, it isn't contained in your list already because you only just created it. The comparison is comparing references, not values.
Why not just use the find statement that you do in the next line instead? If it returns null, then you know there isn't an item already with that type.
So you could do something like this:
var result_item = result_count.Find(x => x.account_type == item.account_type);
if (result_item != null)
{
result_item.count++;
// note here you don't need to add it back to the list!
}
else
{
// create your new result_item here and add it to your list.
}
Note: Find is o(n), so this might not scale well if you have a really large set of types. In that case, you might be better off with Saeed's suggestion of grouping.

You can do:
myList.GroupBy(x=>x.type).Select(x=>new {x.Key, x.Count()});
If you want use for loop, it's better to use linq Count function to achieve this, If you want use Contains you should implement equal operator as the way you used.

LINQ and creating NON anonymous return values

I think I understand returning records of an anonymous type from But in this I want to create NEW CatalogEntries, and set them from the values selected. (context is a Devart LinqConnect database context, which lets me grab a view).
My solution works, but it seems clumsy. I want to do this in one from statement.
var query = from it in context.Viewbostons
select it;
foreach (GPLContext.Viewboston item in query)
{
CatalogEntry card = new CatalogEntry();
card.idx = item.Idx;
card.product = item.Product;
card.size = (long)item.SizeBytes;
card.date = item.Date.ToString();
card.type = item.Type;
card.classification = item.Classification;
card.distributor = item.Distributor;
card.egplDate = item.EgplDate.ToString();
card.classificationVal = (int)item.ClassificationInt;
card.handling = item.Handling;
card.creator = item.Creator;
card.datum = item.Datum;
card.elevation = (int)item.ElevationFt;
card.description = item.Description;
card.dirLocation = item.DoLocation;
card.bbox = item.Bbox;
card.uniqID = item.UniqId;
values.Add(card);
}
CatalogResults response = new CatalogResults();
I just tried this:
var query2 = from item in context.Viewbostons
select new CatalogResults
{ item.Idx,
item.Product,
(long)item.SizeBytes,
item.Date.ToString(),
item.Type,
item.Classification,
item.Distributor,
item.EgplDate.ToString(),
(int)item.ClassificationInt,
item.Handling,
item.Creator,
item.Datum,
(int)item.ElevationFt,
item.Description,
item.DoLocation,
item.Bbox,
item.UniqId
};
But I get the following error:
Error 79 Cannot initialize type 'CatalogService.CatalogResults' with a
collection initializer because it does not implement
'System.Collections.IEnumerable' C:\Users\ysg4206\Documents\Visual
Studio
2010\Projects\CatalogService\CatalogService\CatalogService.svc.cs 91 25 CatalogService
I should tell you what the definition of the CatalogResults is that I want to return:
[DataContract]
public class CatalogResults
{
CatalogEntry[] _results;
[DataMember]
public CatalogEntry[] results
{
get { return _results; }
set { _results = value; }
}
}
My mind is dull today, apologies to all. You are being helpful. The end result is going to be serialized by WCF to a JSON structure, I need the array wrapped in a object with some information about size, etc.

Since .NET 3.0 you can use object initializer like shown below:
var catalogResults = new CatalogResults
{
results = context.Viewbostons
.Select(it => new CatalogEntry
{
idx = it.Idx,
product = it.Product,
...
})
.ToArray()
};
So if this is only one place where you are using CatalogEntry property setters - make all properties read-only so CatalogEntry will be immutable.
MSDN, Object initializer:
Object initializers let you assign values to any accessible fields or properties of an
object at creation time without having to explicitly invoke a constructor.

The trick here is to create a IQueryable, and then take the FirstOrDefault() value as your response (if you want a single response) or ToArray() (if you want an array). The error you are getting (Error 79 Cannot initialize type 'CatalogService.CatalogResults' with a collection initializer because it does not implement 'System.Collections.IEnumerable') is because you're trying to create an IEnumerable within the CatalogEntry object (by referencing the item variable).
var response = (from item in context.Viewbostons
select new CatalogEntry()
{
idx = item.Idx,
product = item.Product,
size = (long)item.SizeBytes,
...
}).ToArray();

You don't have to create anonymous types in a Linq select. You can specify your real type.
var query = context.Viewbostons.Select( it =>
new CatalogEntry
{
idx = it.idx,
... etc
});

This should work:
var query = from it in context.Viewbostons
select new CatalogEntry()
{
// ...
};