Linq-to-XML: Adding Enumerations To Objects?
Oct 2, 2010I'm trying to figure out how to add an enumeration to an object with Linq. For example:
Dim thingBlock = <Things>
<Thing Name="Ish">
<SmallThing>Jibber</SmallThing>
[code].....
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C# - Where And When To Use LINQ To Objects
Feb 21, 2009In which situations I should use LINQ to Objects?
Obviously I can do everything without LINQ. So in which operations LINQ to code shorter and/or more readable?
Enumerations To Array Of (Type) Functions
Apr 11, 2010I usually always use enummerations as a pass ID of some type with a calculated value using the n^2 notation to calculate the return values. It's easy to derive with squareroots what values are derived from a sum; but most of the time I use the Identifier String to denote a combo box drop down list view. I think this is fairly routine for most developers; since in all my coding or rework I have seen it used commonly by other developers also.
Anyway, I wanted to do some sort of comparisson array of strings to fill the combobox using the *.Items.AddRange() function and it requires an array pass (this typically shrinks the code down considerably) and if you want to mix and match arrays in segments it's easier. So here is the code; for doing so I am assuming that other developers use an "AddToArray" type function like me; if not you have to write the function or just replace the code with the actual adding to array.
''' <summary>
''' Convert an enummeration to an array.
''' </summary>
''' <param name="ConvertTo">Convert to return type.</param>
[CODE]...
.net - String Where In LINQ To Objects
Jun 5, 2012I have a linq query like that:
Elementos = From b In Elementos Where b.Value.IdGrupo = 0 Select b
"Elementos" is a dictionary(of long, MyObject). MyObject has approximately 50 properties.
The problem I have is that I have a new requirement to accept string parameter with a "where" condition. Something like "property1>10 and property2 like 'anystring' or property3<=25". (That means any property could have a condition. I have string and numeric properties.)
I'd like to keep using linq, adding the condition as it comes. I'm aware that it could produce an exception if the condition is misspelled or something, but that's acceptable (by try catchs). I wouldn't want to parse the string to build parameters or anything.
LINQ To XML And Child Objects?
Nov 20, 2009I am creating a tool that interfaces with an API for a CD/DVD burner. I have created several custom classes that will hold the information for the disk sets (which consist of a data path and a label file among other information. The DiskSet class has a list of Include objects. My proposed XML output would be something similar to the following:
<DiskSets>
<DiskSet>
<Name>MySet 1</Name>
[code].....
I am attempting to traverse the Includes collection (I have tried List and Binding List as I am also using this in a pair of datagridview controls) and it keeps returning Expression of type 'Object is not queryable. Make sure you are not missing an assembly reference and/or namespace import for the LINQ provider." How can I use LINQ to pull a list of the Include objects under each DiskSet object for transformation into XML? I am hoping to keep this restricted to this one block of code if possible.
.NET Enumerations Of Symbolic Constants For String Values?
Jun 1, 2009I have a list of rather meaningless codes that I'm processing with a VB.NET Windows application. For the business logic I'm writing to process those codes, I'd like to use meaningful constants (like ServiceNotCovered or MemberNotEligible) instead of the original codes (like "SNCV" and "MNEL").As far as I can tell, Enums can only map to numeric values, not to strings. So the best I've been able to come up with is a static class that exposes the constants as static readonly string fields that are internally set equal to the code values, as follows.
Public Class MyClass
private _reasonCode as String()
Public Property ReasonCode() As String
[code].....
PictureBox - How To Access Desired Colors From Enumerations
Jun 8, 2011In my project, it is desirable to access built-in color, dash styles, hatch styles by a numerical index rather than their names. For example, I would like to access the colors in a loop from 0 to 140 and display each of these in side by side rectangles in a picture box. Then later, when I click on the rectangle for a desired color, calculate the index of the color from the position of the rectangle in the picture box and use this index to set another object to the clicked color. I understand the coding for all of this except for how to get the colors from the enumeration in the loop and later, after I get the index from the clicked picture box, how to I access the desired color from the enumeration by using the index obtained from clicking the picture box.
View 5 RepliesAsp.net - Serialize Linq Objects Not Working?
Apr 14, 2010Using the following code:
Private Sub MakeMeSomeXmlBeforeRyanGetsAngry()
Dim db As New MyDBDataContext
Dim customer = From c In db.Customers Select c
[code]....
I am attempting to serialize my linq collection of customers. But it keeps throwing
Type 'System.Data.Linq.DataQuery`1[MyDB.Customer]' cannot be serialized. Consider marking it with the DataContractAttribute attribute, and marking all of its members you want serialized with the DataMemberAttribute attribute. See the Microsoft .NET Framework documentation for other supported types. My issue is that I have already marked the dbml Serialization Mode to UniDirectional and when I check the dbml codebehind all of the DataContract()> and DataMember()> elements are there. I have tried adding various dataloadoptions and setting deferredloading to false, but no luck.
C# - Join The Objects In A LINQ Expression?
Dec 15, 2011How to Join the objects in a LINQ select in this sample (C# variants accepted as well):
Class Room
Public Area As Integer
End Class
Class RoomPair
[code]....
C# - Linq To Objects Outer Join?
Mar 10, 2010Im trying to use LINQ to query Objets. I'm doing the following:
Dim myList As Generic.List(Of MyItem) = (From ThisItem In LinqToSqlObject.Items _
Join Folder In LinqToSqlObject.Folders _
On Folder.Id Equals Item.Id _
[Code]....
This however will not return any item that has a ParentItemId of null. I am trying to do a left join so as to return all "Item" regardless of whether it has a parent or not. I am aware that this is feasible in C# by adding an "into X" on the join, and selecting from X.DefaultIfEmpty(), this however does not appear to work in VB.Net.
LINQ Filtering List Objects?
Mar 1, 2011I have list object and I need to check id in a comma separated string using LINQ in VB.NET, something like this:
dim strId as String = "1,2,3,5,"
dim myList = from objmylist where objmylist.id in (strId)
LINQ To XML Syntax And Class Objects In .net?
Dec 10, 2010I have the following XML file
<Test>
<Modules>
<Module Name= "Test1">
<QueueName Name="Test1Active1" Active="True"></QueueName>
<QueueName Name="Test1Active2" Active="True"></QueueName>
[Code]...
.net - LINQ Union Objects With Same Base Class?
Apr 5, 2011I'm trying to create a list of all my objects from several lists of objects using Union.
Return Chart.AnnotativeNodes.Union( _
Chart.DecisionNodes.Union( _
Chart.EndNodes.Union( _
Chart.StartNodes.Union(Chart.WorkCenterNodes))))
The above line gets an error because I can't union List(of AnnotativeNode) with List(of DecisionNode). Each list defined like List(of EndNode) or List(of StartNode), but each class inherits from the base type Node.Is there a possible way to union these to get a result of IEnumerable(of Node)?
Asp.net - LINQ To Objects Auto-increment Number?
Feb 25, 2009This feels like a completely basic question, but, for the life of me, I can't seem to work out an elegant solution.
Basically, I am doing a LINQ query creating a new object from the query. In the new object, I want to generate a auto-incremented number to allow me to keep a selection order for later use (named Iter in my example).
Here is my current solution that does what I need:
Dim query2 = From x As DictionaryEntry In MasterCalendarInstance _
Order By x.Key _
Select New With {.CalendarId = x.Key, .Iter = 0}
[Code]....
Is there a way to do this within the context of the LINQ query (so that I don't have to loop the collection after the query)?
Check If Objects Follow Sequentially Using LINQ?
May 27, 2011I have an object that looks like follows:
Public Class MyObject
Public Property Key as Intger
get 'Elided for clarity
[code].....
Creating Objects From Child Elements Using LINQ To XML
Feb 1, 2011Is there any way to use a LINQ to XML to query an XML document like the one below to create new (anonymous or strongly typed) objects from the child elements of a descendant? Here is my XML document:
[Code]...
Linq - Merge And Order 2 Lists Of Different Objects?
Mar 15, 2012I 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.
View 2 RepliesLinq To Entities Query With Child Objects?
Oct 13, 2011Basically I have the follwing:Dim ctx As New AdminCoreEntities Dim roles = (From r In ctx.Roles where r.Name.StartsWith("cust") Select r) 'list of System .Linq.IQueryable(Of AdminCoreModel.Role)
[code]...
The error i get when i run this is: Unable to cast object of type System.Data.Objects.ObjectQuery`1[AdminCoreModel.Role] to type AdminCoreModel.Role
Basically I have a many to many situation and I try to get all the Quicklinks objects queried by their roles and not quite sure why EF will cast to a single AdminCoreModel.Role when i.Roles is a collections of objects.
LINQ To Objects, Query Arrays In Object?
Sep 15, 2011I need to query an array. I have tried to use LINQ but with no success.
Here is a simplified structure of Insurance
Public Class Insurance
Public _typ As String
Public _numb As Number()
[Code]....
LINQ VB How To Check For Duplicates In A List Of Objects
Oct 11, 2011I have a list of objects, each with 2 relevant properties: "ID" and "Name". Lets call the list "lstOutcomes".I need to check the list for duplicates (meaning object1.ID = object2.ID, etc.) and set a flag (valid = false, or something) if there is at least one duplicate. Also, it would be nice to send a message to the user mentioning the "Name" of the object, when it fails.I am sure I will need to use the Group By operator to do this, but I am not used to doing that in LINQ, and the examples out there are just not helping me. This article seems to be close to what i need, but not quite and it's in C#.
Here is a starting stab at it...
Dim duplist = _
(From o As objectType In lstOutcomes _
[code]......
help?
LINQ: Creating Objects Of Anonymous Types?
Oct 25, 2011I am in the process of learning LINQ to Objects. I am querying an array of reference elements using LINQ. In the code below, which I have marked with asteriks and PROBLEM, I am having difficulty returning any values for and I suspect its because of the multiple Select arguments.
'Program name:Querying an Array of Invoice Objects
'Created/revised:
'Project description:To demonstrate the use of LINQ to query objects
[Code].....
Order By And Group By In A Linq To Objects Query?
Sep 28, 2010How do I order by and group by in a Linq query?I tried..Dim iPerson = From lqPersons In objPersons Where Len(lqPersons.Person) > 0 Group lqPersons By key = lqPersons.Name Into Group Order By Group descending Select Group, key
For Each i In iPerson
tmp = tmp & vbNewLine & i.key & ", " & i.Group.Count
Next
[code].....
Querying An Array Of Invoice Objects (LINQ)?
Sep 19, 2009I am having a little problem with some homework. Here is the problem:Use the Invoice Class provided to create an array of Invoice Objects. Class Invoice includes four properties- a PartNumber (type integer), a PartDescription (type String), a Quantity of the item being purchased (type Integer), and a Price (type Decimal). Write a Console Application that performs the following queries on the array of Invoice objects and displays the results:
[Code]...
Adding New Objects To Form?
Jul 8, 2011I know that there is a method for doing this but I can't find what that would be. In my program I am looking to allow the user to create new elements(with code behind them) by entering a certain keystroke say ctrl+v(doesn't matter) and adds a textbox
View 5 RepliesAdding Objects In Run Time?
Feb 7, 2011would i do something like "dim txt_whatever as new textbox" or would i do something else?
View 6 RepliesAdding To A List Of Objects
Nov 9, 2011I have an Object structured as follows:[code]I thought this would work but I keep getting the following error: Object reference not set to an instance of an object.
View 1 Replies.net - LINQ Query Returns List Of Empty Objects?
May 3, 2012I have a query that 'selects' object of a type:
Dim l as IList(Of Foo) = (From dataRow As DataRow In table.Select()
Where CStr(dataRow("Column1")) = "A"
Select New Foo(CStr(dataRow("Column1")), _
CStr(dataRow("Column2")))).ToList()
What's happening is that if i set a break-point to the constructor of Foo and step, the constructor is hit and the parameters are loaded with the arguments. However, l has empty Foo objects (the members in every object are Nothing). What could be happening here?
.net - LINQ Sample: Select Typed Objects From A List
Jul 7, 2011I have
Dim objectsList as List(Of Object) = GetAllObjects()
' Filter from Objects just Persons '
Dim peopleList as List(Of Person) = ???
What is the most efficient and effective LINQ expression to do it?
EDIT
1 Dim selectedObjects As List(Of Object) = GetAllObjects()
2 Dim selectedPeople As IEnumerable(Of Person)= selectedObjects.OfType(Of Person)
3 Dim people As List(Of Person) = selectedPeople.ToList()
Error on 3:
Value of type
'System.Collections.Generic.List(Of
System.Collections.Generic.IEnumerable(Of Person))' cannot be
converted to
'System.Collections.Generic.List(Of Person)'.
Linq - Create A Concatenated String From A List Of Objects In 3.5?
Apr 27, 2012I figure I should use 'Aggregate' but apparently I am getting it wrong First I get a list of my Entity objects Dim employers As List(Of myEntity) = (New XXXX()).getZZZ(userName, userType) Then I figured this would be a way to put all the names in a string Dim names as String = employers.Aggregate(Function(current, [next]) current.Name & " " & [next].Name)
[Code]....
LINQ Objects - Group All The MyObjects Together That Share The Same Value And Then Return That Value?
Nov 16, 2010I am having trouble following some of the examples at MSDN for LINQ.Basically I have a List Of MyObject. MyObject has a property called Value which is an integer.I want to group all the MyObjects together that share the same Value and then return that Value where the count of the group is greater than 5.I have tried the following,
dim foak = From o as MyObject in MyObjectList _
Group o By o.Value into Count _
WHERE Count > 5 _
Select o.Value