Is this the most straight forward way to return a typed collection?Here's the key line of code which returns a implicit type of IEnumerable that used to manually loop through to manually recreated a TYPED collection. Is there any native LINQ way to return a typed sorted collection without this recreating of the collection? [code]
View 2 RepliesCan I use LINQ to return an item in a collection that is the same TYPE as the items in the collection? I am a LINQ Noob trying to avoid looping.
Dim mostRecentlyCreatedQuestionnaire As ParentQuestionnaireItem =
CType((From P In questionnaireCollection Order By P.Metadata.CreateDate Descending).Take(1), ParentQuestionnaireItem)
I get an "unable to CAST" error when I include the CTYPE function. I kind of expected that error, but I imagine that if I coul dnot do this, LINQ's usefulness would be diminished and therefore assume that there must be a way..
I'm trying to do a LINQ Query against a typed datatable that will return me duplicated data.With out going into too much detail, here's the basic setup:
strCode1 - string type
intCode1 - int32 type
intAdjustor - int32
There are more fields but these are the ones that are important.I'm going to do my best to describe this, as it's kind of confusing.In theory intCode1 is a key for strCode1 (hence the names). So each time intCode1 is duplicated, the same strCode1 should appear. Example:
[code]...
Ultimately I'd like to get a List(Of T) - where T is my typed data row. In SQL, I would simply use a sub query, to get a distinct list of strCode1 and intCode1, then do a count, grouped by strCode1 where I get more than one row.I'm not sure how to translate that into LINQ, AND get the original types data rows returned in a list.
I have a method, that returns a group of accounts
Public Shared Function GetAllNotesByUser(ByVal UserID As Guid) As Account (??)
Using db As New MyEntity
Dim query= (From A In db.Account _
[Code].....
I would then like to pass this to another function to calculate the totals for all the accounts in the collection. Is it best practice to return an Ienumerable, a generic list, I'm just not sure what works best with LINQ and the entity framework.
I would like the following function to return Nothing if the element with the specified key is not in the collection. Instead, it returns an error - something to the effect of "no element found"
Public Class MyCollection
Inherits System.Collections.ObjectModel.Collection(Of MyType)
Public Function FindByActivityKey(ByVal searchValue As Integer) As MyType
[code]....
I cannot find how to display an error message when what I typed in the listbox field is not in the listbox collection.
For example the listbox contains the following items
1) Apple
2) Strawberry
3) Mango
If for example I type "Mongo" and then press tab to another field, a message will pop up saying I typed something not in the listbox. Anyone who knows how to code if text in textbox1 is not in listbox then blah blah blah.
I want to create a strongly typed multidimensional array or collection containing the following values from a database:[code]
View 3 RepliesI've got the following ADO.NET Entity Framework Entity Data Model:I want to find all the Policyholders with both a Service of a given Id and also a Keyword of a given Status.
This LINQ Does Not Work:
Dim ServicesId As Integer = ...
Dim KeywordStatus As Integer = ...
Dim FoundPolicyholders = From p As Policyholder In db.PolicyholderSet.Include("Keywords").Include("Services") _
Where p.Services.Id = ServicesId _
And p.Keywords.Status = KeywordStatus _
Select p
The Where clause cannot search the p.Services and p.Keywords EntityCollections in that way.
[Code]...
search the collection of a collection in my LINQ Where clause?
View 11 RepliesI am having a problem with the Visual Basic property collection editor .
I have created a Custom Type
Public Class Field
Private Item As Integer
Private Name As String = "FieldName"
[ode]....
I have the following linq query which returns a Report Object; yet I need to explicitly set the value of one of its proprties from another column. [code]...
View 1 RepliesTake the following scenario:
Public Class Store
Public Overridable Property Areas As List(Of Area)
End Class
Public Class Area
[code]....
What's the quickest way to get a total count of shelves for a store? I.e. for a store I get the total count of areas by using Areas.Count Or will I need to loop through each area and tally the count of shelves?
I am using a Strongly Typed Dataset as DAL. I want to return a single column from my table for that i wrote the code as
SELECT DISTINCT Floor
FROM Room
WHERE (Building = @Building)
But when i previewed the data, it shows me all the columns of the table with Null Value and the column with primary key has -1 value. This condition raise an Exception when i link this query to a ComboBox ..
cmbFloor.DataSource = da.GetFloorByBuilding(cmbBuilding.Text)
cmbFloor.DisplayMember = "Floor"
Error: Failed to enable constraints. One or more rows contain values violating non-null, unique, or foreign-key constraints.
I 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)'.
I am binding a Winforms Grid to an entity. (For reasons I won't go into here it must be bound to the entity, not the result a query) The code is as follows:
grid.DataSource = myEntities.entityName.Where("it.field = " & field)
It works, but it obviously isn't strongly typed. Is there a way to define the Where clause of an entity using a strongly typed notation?
How would I create a function to return one database row in a collection, such that the rows column name & value are stored as key/value pairs in the collection?
View 5 Repliesway to return a collection of treenodes which are children of a selected node? I can't find on MSDN a object of treenodes that is a collection of childnodes.
I have two treeviews, and I am writing code that will copy treenodes from one treeview to another treeview if it is selected. If a parent node is selected, I would also like to copy over all the children. If it is just a childnode, then I would like to copy just that.
Here is what I have so far.
Dim treeobj As TreeNode
treeobj = TreeView2.Nodes.Add(TreeView1.SelectedNode.Text)
If TreeView1.SelectedNode.Parent.Index.ToString Is System.DBNull.Value Then
[Code]...
I am doing this within a thread:For Each item As ListViewItem In lvUsers.Items and I am getting: Cross-thread operation not valid: Control 'lvUsers' accessed from a thread other than the thread it was created on.I have been able to adjust a control in a way using something like:
Public Delegate Sub ListAddNameInvoker(ByVal text As String)
Public Sub ListAddName(ByVal text As String)
If lvUsers.InvokeRequired Then
[code]....
But how do I get data from a control and pass it to another thread?
Here is an example of my xml doc:
<?xml version="1.0" encoding="utf-8"?>
<employeedata>
<employee>
<firstname>Bob</firstname>
<lastname>Anderson</lastname>
[Code]...
However, only the first phone number (Office) displays in the listbox. The phoneinfo collection has both <phone> elements, but the For Each statement doesn't seem to iterate thru.
I have a Customer object which has a collection of ContactNumbers. Is it possible with LINQ to get a list of Customers where one of the contact numbers = '123'?
Public Class Customer
Public Overridable Property ContactNumbers As List(Of ContactNumber)
End Class
[Code].....
I'm building flat file content from collections of strings.
Example collection: A, B, C, D, E, etc.
I want to be able to output these values to a string with line feeds in one swoop with Linq if possible.[cod]e...
How to get the last instance of label control in List (of Control) using linq?
View 4 RepliesPrivate Function GetWebDataGridOKButtonId() As String
Dim ctls As ControlCollection = _
WebDataGrid1.Controls(0).Controls(0).Controls
[Code]....
This is not working for me. I am trying to iterate a control collection and return one control ID.
On my view there is a datatable holding a collection of ServerRow and 4 textboxes (Hostname, OS, Location, Zone). When the user types into any of the 4 boxes I want to immediately filter this list. I have this code setup and ready to go that on the set method of each textbox property I call the filter method.
Now onto the problem: if I have 4 criteria that means I have 2 to the power of 4 different scenarios. What I would like to do is write a linq statement with all of these scenarios dealt with such that if any of the properties are NullOrEmpty they will not be used in the Where clause and on the flip side if there is a value the corresponding field will be searched with a Contains.
Example
AvailableCis = New ObservableCollection(Of ServerRow)
(_CiData.Where(Function(ci) ci.OS.ToUpper
.Equals(_selectedOS.ToUpper) AndAlso
ci.HostName.ToUpper.Contains(_ciNameFilterText.ToUpper))
.OrderBy(Function(a) a.CiName))
This example shows how it works with 2 criteria and both of those criteria are set.
Is it possible to use LINQ to query the items collection of a ComboBox & get the index of the item that matches what I'm looking for?
View 4 RepliesI have the following XML which I load via XDocument.Load(uri) or XElement.Load(uri). I am having trouble getting a collection of <asset> elements via LINQ.
Here is a snippet of the XML I'm trying to query:
<assetCollection xmlns="tag:aisle7.net,2009:/api/1.0">
<title>All Assets</title>
<description>Collection containing all assets in the system</description>
<resourcePath>/us/assets/~all</resourcePath>
[Code] .....
Using LINQ, How do I only get the author element value for the following XML: [code]but n.value returns the author and all the child element values.
View 3 RepliesI have a method that takes in an id, a start date, and and end date as parameters. It will return rows of data each corresponding to the day of the week that fall between the date range. The rows are all doubles. After returning it into a DataTable, I need to be able to use LINQ in VB.NET to return the maximum value. How can I achieve this? Here is the initial setup?
[Code]...
Currently, I am using a loop to find the row I want to update.
Public Sub pubsub_SetUserDGVColumnWidth(ByVal sender As Object, ByVal e As System.Windows.Forms.DataGridViewColumnEventArgs)
' update all user settings for the given column
[Code]....
I am using LinqPad to learn Linq by querying the NetFlix OData source.Here is the query I got working which is awesome.[code].....
(Pardon all the comments...it is a testament to the fact I am experimenting and that I will change the query for various needs).There are two thing I cannot figure out.First.Let's say I only want to return the first 10 results.Second (and most importantly). I want to filter by a partial string of the genre.Each title contains a Genres collection. I want to show only Genres where the Name contains a certain string (like "Family").Even better filter using Titles where genre.name.contains "firstFilter" AND "secondFilter".Basically, I want to filter by genre(s) and I cannot figure out how to do it since Title contains its own Genres collection and I cannot figure out how to return only title that are in one or more genres of the collection.