VS 2010 : Counting Instances Of A Query In LINQ?
Sep 24, 2011
How would I go about counting the number of times a given query occurs inside of a text file using LINQ?I need to search through the attached file and see how many justices were appointed by each president, and then create a new text file displaying the following:
presName, justiceCounter 'president name ordered by first name, number of justices appointed
I pretty much get how to do everything except for keeping an accurate counter within the LINQ query. However, I do feel confused about the order in which I should write this code, as in where I should keep my counter for how many justices a given president has appointed.
My output is displaying like this:
Abraham Lincoln,111
Abraham Lincoln,111
Abraham Lincoln,111
[code]....
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Mar 7, 2012
Is bindingsource.count only used to give the total items in a list? I'm trying to prepare data for a pie chart, and need to count the instances of different items in a column (If there's a way that the Chart will do this itself, I've not been able to find it, it seems to need linked items and values). The bindingsource is already filtered and would prefer not to combine filters.Would it be best to loop through the rows of the column and count them 'manually' or is there a quicker way of doing this?Put it in a datagridview? Is it possible to use Aggregate Count on a bindingsource?
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Jun 5, 2011
i need to count the no of instances of a word in a string using vb.net i can do the usual way as my problem is a little different for eg i need to count the no of occurrences of -> in tree_ptr->sub.another->valu=3;
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Sep 22, 2009
I know that LINQ queries are deferred and only executed when the query is enumerated, but I'm having trouble figuring out exactly when that happens.Certainly in a For Each loop, the query would be enumerated.What's the rule of thumb to follow? I don't want to accidentally enumerate over my query twice if it's a huge result.
For example, does System.Linq.Enumerable.First enumerate over the whole query? I ask for performance reasons. I want to pass a LINQ result set to an ASP.NET MVC view, and I also want to pass the First element separately. Enumerating over the results twice would be painful.It would be great to turn on some kind of flag that alerts me each time a LINQ query is enumerated. That way I could catch scenarios when I accidentally enumerate twice.
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Aug 15, 2011
I have a table called Ordersthe table has many rows but im only interested in two in particular.I want to query the table so it returns the average ordered count of each producti want to know what is the average count of the ordered products, but now in total but per productID instead.
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May 9, 2012
I want to create a LINQ to entities query getting data(join) out of two tables and bind the result as datasource to a datagridview.
Unfortunately I seem to stumble upon a syntax issue.
Table 1 : dcpricing.tblpricing
Table 2 : dcpropertydetail.tblpropertydetail
Grid: grdpricing
[Code].....
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Mar 24, 2011
I am creating a mediaplayer / playlist creator tool that basically imports MP3 songs into playlists (grids). I'm looking to add search functionality where the user can search all open playlists (or a subset of the open playlists). A Playlist is basically a collection of AudioFiles, where an AudioFile is a class that holds the filename of the MP3 file and then exposes the tags (Title, Artist, Album, etc) in public properties.
The idea is that the user can search for a certain expression (for example "the"), and that he can then choose whether to search in the title, in the title and artist, in the title or artist, in the title, artist and/or album, etc. However, I'm having a hard time implementing this and also having it kind of dynamic.
At the moment I am simply gathering all the AudioFiles from the open playlists (or from the subset of playlists the user chooses) and then running a simple LINQ query to find those AudioFiles where the Title contains the search text. Then I display the resulting AudioFiles in a new playlist window:
[Code]....
In case the AND / OR distinguishing is too hard, I would be happy to start with just letting it default to 'OR', so that the user can check Title and Album for example. If he would then search for 'a' then all songs that contain 'a' in their title as well as all songs that contain 'a' in their album should be returned. I guess that makes it easier, but I still wouldn't know how to dynamically create the LINQ query.
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Jul 14, 2011
given this function:
Public Function Search(ByVal StartIndex As Integer, _
ByVal MaxResults As Integer, _
ByVal AccountNumber As String, _
ByVal LastName As String, _
[Code]....
instead of what I expected:
Select count(*) from remitline where lastname = "smith"
What am I doing wrong building up the where clause? I'm using Castle ActiveRecord 2.1
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Aug 6, 2009
if there is that much of a performance gain in running a LINQ stored procedure versus a LINQ query?
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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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Mar 31, 2011
Forgive my ignorance on this.I have this LINQ Query:Dim ngBikersDataContext As New CarBikeWalkDataContext
bikersList = (From c In ngBikersDataContext.Reg_Bikers _
Order By c.L_Name _
Select New Bikers() With { _
.BikerID = c.BikerID, _
.F_Name = c.F_Name, _
[Code]...
with the error "Overload resolution failed because no accesible 'Select' accepts this number of arguments."
Over the "NEW" I get an error " ')'expected."
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Jan 27, 2011
We are doing a query against an in-memory collection of LINQ data objects. The wrinkle is that we are ordering by a column in a related table whose records have not necessarily been loaded yet (deferred loading:)
Dim oPkgProducts = _
From b In oBillPkg.BillProducts _
Where b.Successful.GetValueOrDefault(Common.X_INDETERMINATE) = _
[code]....
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Aug 31, 2011
How do I add ROW_NUMBER to a LINQ query or Entity? How can I convert this solution to VB.NET?
[Code]...
I'm having trouble porting that last line. I have been unable to locate a VB.NET example. I'm actually not looking for any paging functionality like the example provides, just good old-fashioned Row_Number(Order By X) row index.
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Apr 20, 2010
I just upgraded a project from VB 2008 to VB 2010. Before, the project did not use LINQ. I have started implementing it. So, I have updated the target framework from 2.0 to 3.5, and added a reference to System.Core, and imported the namespace System.LINQ to the entire project and also imported System.Data.LINQ into the form I'm working with (because it was not available in the list for Imported Namespaces in the references tab).
It's not throwing any errors now, but my IntelliSense is not working for LINQ stuff.
For example... I write this:
[CODE]....................
Then, if I type S. on the next line, the IntelliSense doesn't grab what it should for S (Only get Equals, GetHashCode, GetType, ReferenceEquals, and ToString, instead of the options I should get like Count, First, FirstOrDefault, etc...). If I Type S.First. then its the same thing, no IntelliSense that lists the available fields for S, just the standard options (Equals, GetHashCode, GetType, ReferenceEquals, and ToString). I should be seeing my column names in my table when I type S.FirstOrDefault.
So any ideas what is going on? When I type the code, for example, MessageBox.Show(S.FirstOrDefault.FirstName), it works perfectly. But it doesn't change the casing of the text (so it would read s.firstordefault.firstname) and no intellisense while doing it. But no errors. BTW - Everything works perfectly when creating a NEW VS 2010 application, it's just my projects upgraded from Visual Basic 2008 that have this issue.
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Apr 16, 2011
I was wandering is it possible to use a query within another query below is the code I am trying to use.
Public Function GetInventByComp(ByVal CompID As String) Using DC As New DataClassDataContext
'need to get company id's based off names? thats bad should be name from Id need to rethink this
Dim invent = (From C In DC.Inventors_Companies _
Where C.CompID = CompID _
Select C.InventorID).ToString
[Code]...
I was trying to us multiple values in a string like "1, 3, 5" but I can't seem to get that working either so I am trying to use just a single value now. Can anyone help me? "Yes I am new to this"
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Feb 21, 2012
I have a problem with summing up the number od TextBox-es placed on several TabPages of a TabControl. The next line works fine without TabControl:
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May 9, 2010
I have a form with four chart controls on it and i would like to count them at runtime but i'm hitting a snag.
For Each ctrl As Control In Me.Controls
If TypeOf ctrl Is System.Windows.Forms.DataVisualization.Charting.Chart Then
Label1.Text = ctrl.Controls.Count
End If
Next
the count is returning zero when it should be returning 4 - what am i missing?
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Sep 22, 2010
I'm working on a program that uses a COM Object exposed by a .dll. The .dll has a known bug, though, where it acts very erratically when more than one instance of the object is created under one .dll, resulting in crashes or corrupted data a large part of the time. I'm curious if there is some way I can load another instance of the .dll itself, then create another instance of the object without having to need a new process for every instance.
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Mar 13, 2012
there are any nifty in-built .net methods that can essentially return either the number of occurrences of each element in an array, or simply return the modal value.
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Jan 24, 2012
I'm a little out of my comfort zone here having programmed in VB6 quite a few years ago things have changed a lot since then.My issue is I have a class that I've built which works with no issues but I would like to be able to keep a 'handle' of some description on this class so I can also make adjustments to it's parameters when the user changes something. My problem is that I need to do this for an unknown quantity of these class instances.
In the VB.Net language how would I create an instance of this class that could be accessed by any Sub within the application and each instance created can be individually accessed by specifying some sort of identifier?
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Jul 31, 2011
I'm creating a twitter account manager using the Twitter API. I have multiple accounts, over 10 of them. I want to automate all 10 of these accounts to do certain things, now the way I started to code the program was so that it would accommodate only one account, and all the codes worked perfectly and were managed by individual timers for individual processes that I wanted done. i could tweet between certain intervals, follow people who tweet certain things without me being on top of it.
Now the problem is that I've been trying to create new instances of subs that I've already created so that I dont have to create 10 new subs with the exact same procedures. I'm pretty sure it's impossible to create copies of subs dynamically or within a loop but it didn't stop me from trying. So question is how can I edit a program that was designed to accommodate and automate only one account, to potentially accommodate over a 100? I don't need codes or anything I need ideas so I can try them, but right now I'm completely blank.
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Jun 6, 2012
I'm trying to code to run 2 instances of the same client at the same time.Using a simple form with a button with system.dyecnostic.process.start(program path) to run the instance to start with.Now the problem starts with trying to run a second it just loads and closes and sends me to the first. how to negate this so I can get 2+ of the clients up?
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Oct 12, 2011
I have a problem that can be best solved with LINQ. I have a class that has 2 properties of which 1 is a single. I have a collection of that class and I need to select the instance with the highest single value.[code]I'm having a hard time explaining this even this is a simple task. Please ask if you don't understand.In addition to my original question, How would I create a collection containing the 5 highest Instances.
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Oct 12, 2011
I am just getting started with VB.NET - what I couldn't find in my book is whether a new instance of an object with the same variable-name will delete the previously stored values - or will that somehow remain in memory?This is the scenario:
I open a data file and load the contents in 'Dim var As New dataObject'what happens when I again open another file and the same line is encountered:Dim var As New dataObject'
Hope the question is clear p.s. the dataObject is a simple structure with a bunch of variables in it - nothing fancy.
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Jun 23, 2010
Like i have. Dim MainWindow as new Classic.
But i have another i need to Access.
Is there a Way. Ive Tried and Tried. But i can't find a Way to Load another.
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Sep 4, 2009
I've been reading a fair bit about the performance of using LINQ rather than using a for each loop and from what I understand using a LINQ query would be a little bit slower but generally worth it for convenience and expressiveness. However I am a bit confused about how much slower it is if you were to use the results of the query in a for loop.
Let's say that I have a set called 'Locations' and a set of objects called 'Items'. Each 'item' can only belong to one 'location'. I want to link items that are under the same location to each other. If I were to do this using a normal 'For Each' loop it would be something like this:
For Each it as Item in Items
If it.Location.equals(Me.Location)
Me.LinkedItems.Add(it)
End If
Next
However if i was to use LINQ it would instead be this:
For Each it as Item in Items.Where(Function(i) i.Location.equals(Me.Location))
Me.LinkedItems.Add(it)
Next
is the second (LINQ) option going to loop once through the entire 'Items' set to complete the query, then loop through the results to add them to the list, resulting in essentially two loops, or will it do the one loop like the first (For Each) option?
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Mar 24, 2012
Is it possible to do the following? [code] Basically I have one Load_Gridview function that is called on all postbacks, and rather than creating a bunch of different cases.I want the filters to stack.My actual code has more filters set up (4 or 5 of the).It all compiles ok but when I run and try to execute with active checked, or a department selected I get the following error. [code]
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May 5, 2009
I have below XML file
<?
xml version="1.0" encoding="utf-8" ?><
PageFlow>
<
attributegroup name="Search"><
attributes>
[Code]...
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Apr 18, 2012
I am looking to sum the "Status" field.
Dim _detailRecords As New DataTable
_detailRecords.Columns.Add("y")
_detailRecords.Columns.Add("z")
[Code]....
I'm also wanting to keep this as an IEnumerable of DataRow because I will be creating a datatable from it with
Dim yyyyy As DataTable = query8.CopyToDataTable
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Aug 13, 2010
I am Fairly new to Linq and I am trying to write a simple query to return the error messages within my xml file.
<?xml version="1.0" encoding="utf-8"?>
<Error xmlns="urn:xxxxx">
The following errors were detected:
[code].....
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