Use LINQ To Find Complex Combinations Of Items In Two Lists?

Jun 28, 2010

This question is very similar to a previous question of mine, Use LINQ to count the number of combinations existing in two lists, except with some further twists.

I have a list of CartItems that can receive a discount based on the items specified in the list of DiscountItems. I need to be able to pull out the items in the Cart that can receive a discount and apply the appropriate discount specfied in the DiscountItem. The discount is only applied for each combination that exists. Here's what the two lists might look like to before the discount is applied[code]...

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.net - Use LINQ To Count The Number Of Combinations Existing In Two Lists?

Jun 17, 2010

I'm trying to create a LINQ query (or queries) that count the total number of occurences of a combinations of items in one list that exist in a different list. For example, take the following lists:

CartItems DiscountItems
========= =============
AAA AAA

[code]....

The result of the query operation should be 2 since I can find two combinations of AAA and BBB (from DiscountItems) within the contents of CartItems.My thinking in approaching the query is to join the lists together to shorten CartItems to only include items from DiscountItems. The solution would be to find the CartItem in the resulting query that occurs the least amount of times, thus indicating how many combinations of items exist in CartItems.When CartItems is filtered to only the items in DiscountItems, it can be visually displayed like this:

CartItems that get a discount
=============================
AAA BBB <= This combination is eligible for a discount
AAA BBB <= This combination is eligible for a discount
AAA <= Not eligible

Thus, because there are 2 combinations of the discount in the Cart, the result is 2.Here's the query I already have, but it's not working. query results in an enumeration with 100 items, far more than I expected.

Dim query = From cartItem In Cart.CartItems
Group Join discountItem
In DiscountGroup.DiscountItems

[code]....

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Combinations Of 16 Take By 2 Using LINQ

Oct 28, 2009

I want simply to generate rapidly combinations of 16 take by2 using linq.So I want to display me the combinations only not arrangements:1,2 (not 2,1 because there are combinations)...1,16 2,3 (not 3,2) because they are combinations..2,16..Comb of 16 take by 2 makes 120 so 120 combinations will be displayed on screen.[code]So my question is how to display rapidly on screen the combinations of 16 take by 2 using this Enumerable class of Visual Basic .NET(the 120combinations in fact)

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.net - Building A LINQ Expression To Find Items Related To All Descendants Of A Tree Node?

Mar 7, 2011

I have built a database structure that represents a category tree to help classify some of the data we have stored. The implementation is that each record in the Category table has a nullable foreign key back into the Category table to represent the parent Category of this category (one-to-many), essentially allowing for subcategories within a broader parent level. There is a CategoryMembership table that links a record in the Item table to its respective Category (many-to-many). I have created the DBML for this database, and it has a member access structure that includes the following:

[Code]...

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LINQ To XML To Create Complex XML File?

Feb 9, 2012

I would like to know if there is any simple/fast way to create a complex XML file, when I say complex, I mean more than 20 elements encapsulated. Although this is VB.net,unfortunately literals will not work in this case

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.net - Generate Complex Object From LINQ To XML In .NET?

Apr 1, 2009

I have an XML File that I am processing using LINQ. I want to basically serialize the XML data into custom objects but don't know how.

[Code]...

How can I finish the above LINQ query to populate the Children property of the Group object?

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Returning Subset Of Dictionary With A Complex Type As A Key With Linq

Oct 5, 2010

I have a collection as follows

Private _bankRates As Dictionary(Of RateSourceBank.Key, RateSourceBank)

Where RateSourceBank.Key is simply

Public Class Key
Public RateType As String
Public EffectiveDate As DateTime

[Code].....

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Sql Server - Converting Complex Sql Stored Proc Into Linq

Jan 24, 2011

I'm using Linq to Sql and have a stored proc that won't generate a class. The stored proc draws data from multiple tables into a flat file resultset. The amount of data returned must be as small as possible, the number of round trips to the Sql Server need to be limited, and the amount of server-side processing must be limited as this is for an ASP.NET MVC project. So, I'm trying to write a Linq to Sql Query however am struggling to both replicate and limit the data returned. Here's the stored proc that I'm trying to convert:

[Code]....

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Complex Filtering Datagridview Items

Aug 15, 2011

I wanna search items like MS windows search for example if i wanna search mp4 files i should write "*.mp4" its enough my searching but if i ll use filter function i cant do this on datagridview couse when i want to search something i need to know full name of this record... its to bad for me... is there any way? can i do it?

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Know If An Array Of Lists Contains Similar Items (similar Lists)?

May 20, 2010

I know how to check whether an item exists in a list using (MyList.Contains), But I do not know how to check the whole list. For example (use one button and one richtextbox):

[Code]...

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Merging 2 Lists In LINQ?

Jun 9, 2011

I have two Lists of custom objects:

List1: Year, Month, ValueA
List2: Year, Month, ValueB

I want to get a third List with a merge between the two:

List3: Year, Month, ValueA, ValueB

Is there any elegant way to perform that in LINQ VB.Net?

Example:

List1:
2010 - 6 - 2
2010 - 7 - 5

[Code].....

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How To Build A LINQ Where Source Is Made Of Different Lists

Jul 4, 2011

Suppose that I have more than one List (L1,L2,L3,L4) of instances of a class [code]Now I want to querry the 4 lists with one call like Dim L= (from P as MyClass in (L1,L2,L3,L4) where p.Datetime> XXXXX order by p.datetime select p).tolist..is it possible to do something like that? I Know that I could do a FOR NEXT loop with each list but i am looking for a way to do this with a single call

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Linq - Merge And Order 2 Lists Of Different Objects?

Mar 15, 2012

I have collections of 2 different types - let's call them Cars and Trucks. Both share base class Vehicle, which has property Passengers.I want to merge them into a single collection ordered by that property. E.g., merge Cars and Trucks and order by Passengers.

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C# - LINQ To Object Comparing Two Lists Of Integer For Different Values?

Sep 19, 2010

I accept both C# and VB.NET suggestion, even though I'm writing an app in VB.NET I have two lists of intergers

List1 {1,2,3,5}
List2 {2,4,6,7}

I want to have new List3 {4,6,7} which is composed of elements of List2 that are not in List1. I know I can write a nice For Each loop for this but I want it done in LINQ I've been looking for such methods at Enumerable Methods, but I can't find it.

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Find The Common Parts Of Lists?

Jan 27, 2011

Suppose I have two list

list1: {1,2,3,5}
list2: {1,2,2,3,3,4}

I want to get the result list3: {1,2,2,3,3,4,5}

notice the final result contains the common parts between two lists.

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Selecting Items At Same Index In Multiple Lists?

Apr 6, 2012

I am working on a project for software engineering where we are trying to create a warehouse inventory system. I have created an inventory page where I can add/delete/search for an item as well as access invoices and reorder items... i am struggling on the delete item part. I have my design set up where there are four different lists on my page. One for name, one for serial number, one for RFID number and one for amount in stock. I want to be able to select an item by name and its information in serial number, rfid, and amount also select and have no idea how to go about this..I wanted to use four different lists because I need to be able to delete an item from the list and it remove just one from that stock and not the entire item unless there is only one of that item left in stock.

for my inventory page

Public Class InventoryDepartment
Private Sub InventoryDepartment_Load(ByVal sender As System.Object, ByVal e As System.EventArgs) Handles MyBase.Load

[Code]....

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.net - Find Common Values In Several Arrays Or Lists

Dec 23, 2011

Find common values in multiple arrays with PHP Pretty much does what I need, but in PHP, I need VB. My situation is I am trying to create an intelligent stock pick system based on multiple stock locations. At the point of invoicing, we loop through the items invoiced and check the stock database for available stock.

If all items on the invoice are available to pick from stock location 1, then all should be picked from stock location 1... etc. If all most items are available from stock location 1 except one or two, then pick all stock from stock location 1 except for the exceptions which should be picked from the location with the highest available stock. Finding highest available stock is simple, but I can't work out how to analyse the stock availability from multiple locations and finding the common stock locations.

[Code]...

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Finding Equality In Items In Two Lists Of Differing Types?

Jun 9, 2009

I have two objects that are derived from same the base class. ets say ObjA is the base class, and ClassB and ClassC inherits ObjA. f I have a dim lst1 as List(Of ClassB) im list2 as List(Of ClassA)nd and I want to check for the existence of something being in lst1 that it is in list2, now I am only interested in comparing against one key bit of information that it is declared in the base class and is a string. How can I iterate through the lst1 comparing against list2? I thought I could I overload/override the Equals method but I am having no joy for either of the classes and say some thing similar to

Public Overloads Overrides Function Equals(ByVal obj As Object) As Boolean
Dim temp As ClassA = TryCast(obj, ClassA)
If temp.Id = Me.Id Then

[code].....

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VS 2010 - Multiple ComboBoxes And Dropdown Lists With Different Items

Jul 16, 2010

I have multiple combox boxes,
A B C
Combobox B has items Fruit, Veg, Dairy
Combobox C needs to contain 3 list and depending on what value is selected in Combo Box B.

For example,
If I select Veg in Combo Box B, I would like to have a drop down list containing "tomatoes, lettuce, onion,..........."
If I select Dairy in Combo Box B, I would like to have a drop down list containing "Milk, Cheese...................."

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Asp.net - Complex Linq Query - Add A .Where() Or .Any() Predicate To Reduce Query Complexity (in VB)?

Sep 14, 2010

I have to join two main tables, and I need to filter the results by elements in an ASP.NET web form. These filters are created on the fly so I have to use a lot of where extensions to filter the query. I want to execute the query with as optimized SQL as possible.

I am first doing a simple join between TW_Sites and TW_Investigators. Then there are two sub-tables that are involved. TW_InvestigatorToArea and TW_InvestigatorToDisease. While most of the where clauses are working fine, I have found a performance issue that won't be an issue right now, but will be an issue as the table gets bigger.

The arrays DiseaseCategories and DiseaseAreas would be the results of a CheckBoxList result.

Protected Sub LoadResults()
'Get Dictionary of Filters
Dim FilterDictionary As OrderedDictionary = Session.Item("InvestigatorFilterDictionary")
' Initialize LinqToSql

[code]....

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VS 2008 - Linq Statement To Go Through A Dropdown Menu's Sub Items And Get What Items Are Checked

Apr 8, 2010

I have the following linq statement to go through a dropdown menu's sub items and get what items are checked: vb Dim UnselectedItems = From xItem As ToolStripMenuItem In tsiSelectObjects.DropDownItems Where TypeOf xItem Is ToolStripMenuItem AndAlso CType(xItem, ToolStripMenuItem).Checked = False

I get this error tho: Unable to cast object of type 'System.Windows.Forms.ToolStripSeparator' to type 'System.Windows.Forms.ToolStripMenuItem'. As you can probably guess i have ToolStripMenuItems and separators in there

However the AndAlso should short circuit in the case where the item is not a ToolStripMenuItem and it doesn't seem to be doing so (as TypeOf xItem Is ToolStripMenuItem=false in this case)?

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LINQ To SQL "complex" Select?

Sep 5, 2011

I have Country=>Ligue=>Team(Name, Score)I need to select all team Name-Scores from a country.

something like this, does not work )
query = from ligue in myCountry.Ligues, from team in ligue.Teams
select name = team.Name, score = team.Score distinct

[code]....

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Sorting 2 Lists Based On Only One Of The Lists?

Apr 1, 2011

I have two lists. One list is a list of names, the other list is a list of how many times each name is found in the first list noted in the database

so...
Nick
John
Jim
Jack

is the firs tlist

10
13
13
2

is the second list. Nick had 10, john 13 and so on.I want to sort the second list from large to small, but have the index for the first list still linked to the correct amount of calls.i do it this way so I can

for x = 0 to num_of_names
string = lst_name(x) & "-" & lst_count(x)
next x

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C# - Pick Out A Group Of Items Using Linq To Xml

Jul 4, 2011

My head is fuzzled with this. I have an xml doc which has the layout for a grid stored in it. If you notice the columns are stored as "Items" in the XML. I am trying to retrieve each "Item" out of the XML using LINQ but no matter what I do I keep taking on straggler properties that I don't need.

[Code]...

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Linq Group Count Items?

Dec 5, 2011

I have this linq to entity

From r In ReceiptRepository.Fetch
Where
r.RECEIPTDATE >= ReportStartDate And

[Code]....

This is working fine, except the count property, it is just giving the number of group count. I don't know how to find out each Tender Count

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Linq Partial Sorting Items?

Aug 19, 2011

I have an issue for ordering items using Linq[code]...

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Find A DataTable Row By Column Value Using LINQ?

Jan 7, 2012

I have a Dynamic DataTable Created at runtime. The Setup is like so

Id | Name | Age
-----------------
3 | Mike | 21
6 | John | 43
8 | Sara | 34

What I am trying to do is come up with a linq statement I could use to find and update specific rows.

Such as a statement to change AGE to '33' WHERE ID = '3'

My code So far is:

-[VB.NET]-
Dim MyRow As DataRow = From column In MyTable.Rows Where column("Id") = 3
MyRow(0)("Age") = 33

But this is not updating my DataTable entry.

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How To Find Average In LINQ Query

May 3, 2010

I tried the following code:
Dim T5NHCEDCavg As Double
qry = From employee In empList
Where employee.HCEDC = False And employee.X5 = False _
Select employee.DCFSA
T5NHCEDCavg = qry.Average

But I'm getting a design-time error that says "Overload resolution failed because no accessible 'Average' accepts this number of arguments." I realize that I'm missing an overload here, but I'm not sure what to use or how to do this. I'm pretty new to LINQ. I've got a dataset in memory that I'm querying, and there is a double-precision property DCFSA, of which I'm trying to get the average based on my query above.

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Linq : Find Item In DataRow[]?

Sep 28, 2011

gefundeneID = drTerminal.AsEnumerable().Single(Function(s) s("TerminalID") = RandomID)Have an array of DataRow and want to look if the RandomID is in one of the rows.What's wrong with this code?

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Use LINQ To Find Certain Numbers Within An Array

Apr 13, 2011

I've been assigned a homework assignment where I need to use LINQ to find certain numbers within an array. I've read through the book and some online tutorials, for some reason I just can't seem to understand it. I'm not asking anybody to do my homework for me... Just asking if anybody could explain it better, maybe in more detail?

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