Comparisons For A LINQ Except Query Using Primitive Datatypes?
Jan 13, 2012Anyone have any insight on the Big O notation for comparisons for a LINQ Except query using primitive datatypes? I couldn't find anything on google.
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LINQ Query Is Enumerated - Turn On Some Kind Of Flag That Alerts Me Each Time A LINQ Query Is Enumerated?
Sep 22, 2009I 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.
.net - ActiveRecord Linq/NHibernate Linq Not Building Query Completely?
Jul 14, 2011given 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
Performance Gain In LINQ Query Vs LINQ Stored Procedure?
Aug 6, 2009if there is that much of a performance gain in running a LINQ stored procedure versus a LINQ query?
View 1 RepliesAsp.net - Complex Linq Query - Add A .Where() Or .Any() Predicate To Reduce Query Complexity (in VB)?
Sep 14, 2010I 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]....
LINQ Query Using The Dynamic LINQ Library?
Mar 31, 2011Forgive 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."
"System.ArgumentException: An Item With The Same Key Has Already Been Added." When Trying To Order An In-memory LINQ Query By A LINQ Association?
Jan 27, 2011We 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]....
LINQ To SQL - Add In Row_Number To A LINQ To SQL Query?
Aug 31, 2011How 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.
VS 2008 Linq Possible To Use Query In Another Query?
Apr 16, 2011I 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"
VS 2008 Comparisons Of Strings
Aug 30, 2010I have a database of tables that I needed to do some comparison work on and sql server is limited to the means of doing string comparisons. I put all the data into lists and thought of using [URL] or string.contains but does not seem like it is working right. It is large amount of data and I need to be able to make some matches in order to avoid the manual checking of each string. Here is sample data and code;
[Code]...
Perform Element Comparisons Between Arrays?
May 7, 2012I ran into a situation where I have to compare an element in one array to the corresponding element in a separate array of the same size. I've tried using Google and search for the answer though all searches came up nothing I could use.
[Code]...
Tell If An Object Supports Scalar Comparisons?
Mar 6, 2010how i would check to see if a given class supports the >, = and < operators?
Given an object passed in, I am looking for code that implements the following logic:
If GetType(someObj).SupportsScalarComparisons() Then ...
I don't know if this is a case for Reflection, or ?
VS 2008 - Any Shortcut To Directory Comparisons?
Jan 5, 2010I'm developing a relatively quick-and-dirty approach to copying some files over. The situation is that I have a point on the network where a master directory is located. This directory includes the official directory structure as well as all official files. The user's local machine should have a place in their C:Program Files directory that has the exact same directory structure.
If it doesn't, the application should create it and copy files over based on the network master. If the user's local machine does have the appropriate folders in place, then any newer files found in the network master directory should be copied over to update the user's local files. It seems to me that this would require knowledge of the root directories up to the point of the network master and the same for the local directory.
At first glance, this looks to be a bit more complicated to accomplish than I was thinking it should be. Are there any shortcuts to using say the Directory/DirectoryInfo, File/FileInfo classes, etc that would allow this to be accomplished? I'm trying not to overcomplicate it as I need to get something out pretty quick. But the answer just doesn't seem to be showing itself.
.net - Should Use LINQ For This Query
Sep 4, 2009I'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?
Can Do A LINQ Query Of A LINQ Query?
Mar 24, 2012Is 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]
View 4 RepliesLinq Query In .net?
May 5, 2009I have below XML file
<?
xml version="1.0" encoding="utf-8" ?><
PageFlow>
<
attributegroup name="Search"><
attributes>
[Code]...
Put A Sum() In Linq Query?
Apr 18, 2012I 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
Query With Linq To Xm?
Aug 13, 2010I 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].....
C# - Conversion Tool Comparisons For Visual Basic 6.0?
Apr 5, 2009Has anyone here used either of the following (or any other tool) to convert your vb6 code to a .net language?Artinsoft's upgrade companion (converts to c# and vb.net)
vbmigration partner(converts to vb.net)How effective were they and what size project did you convert?
How much work was left to do afterwards?How happy are you with the resultant .net project.What was the support like?Is there a support forum anywhere for users of tools like these, neither vendor seems to offer one.What did they charge, their prices are not published and I have heard wildly differing prices from different sources for both the above examples
What Am I Missing About Numeric Comparisons In This Simple Delegate Example?
Jul 26, 2011I am looking specifically at the ShowInOrder method which has been passed the delegate function CompareNumbers. I am trying to figure out exactly what is going on here:
If compare(_num1, _num2) Then ...Here is the full sample.
Module Module1[code]....
C# - Is String A Primitive Type
Oct 19, 2010I am curious about the string and primitive types. Article like this says string is primitive type. However second article on MSDN does not list string as primitive type. However when I ran the code provided in second article, it displays String is not Primitive type.
View 8 RepliesCreate Our Own Primitive Type?
Oct 31, 2009there anyway that we can create our own primitive type? let's say we call this
Code:dim test = 4 then test will automatically be an integer right but i wanted this
Code:dim test = 4% and i want test not to be an integer, but a percentage_integer, in other words, my own primitive type. is that possible?
Why The Sql Query Is Different On That Linq Query When Run On C# And On .net
Aug 26, 2009if I run this under c#
from p in Addresses where p.Address2 == null select p.AddressID
it generate this query
SELECT [t0].[AddressID]
FROM [dbo].[Address] AS [t0]
WHERE [t0].[Address2] IS NULL
if I run this under vb.net
from p in Addresses where p.Address2 = nothing select p.AddressID
it generate this query
SELECT [t0].[AddressID]
FROM [dbo].[Address] AS [t0]
WHERE [t0].[Address2] = ''
p.Address2 is a varchar field that accept null value
why vb.net is "wrong" ?
Benefits Of Different Datatypes?
Jun 8, 2009I was wondering, what are the benefits of having a variety of different data types available to programmers?
View 1 RepliesHow To Convert DataTypes In VB
Jan 2, 2011I am working on a produce inventory database in my VB Express program. I have a form on the bottom and a spreadsheet at the top. I want to enter all the data in the form and have that data automatically transferred as a group to the spreadshet in the upper part of the page when I press a button.
I know that there's an insert function. I set it up correctly. The problem is that I have to convert the textbox, which contain string data, to the datatype used in the database spreadsheet. HOw do I use CAST or do this?
Here's the function I am using:
Me.TableAdapterManager.InventoryTableAdapter.Insert(IDTextBox.Text, fruitName, unitprice, unitsize, unitIn, unitTransit, unitOut)
Evernything is a string cause the data is coming from a textbox, I need to convert it to the datatypes used in the database.
.net - Converting Linq To XML Query From C# To .Net?
Dec 1, 2009I'm converting the Linq query below from C# to VB.Net. Can you spot my error? The query joins 3 XML datasets. C# - This one works great.
List<Course> courses =
(from course in CourseXML.Descendants(ns + "row")
join coursecategory in CourseCategoryXML.Descendants("Table") on (string)course.Attribute("code") equals (string)coursecategory.Element("DATA")
[code]....
.net - Dynamic Linq Query?
Mar 14, 2011I have been trying the following but it returns unexpected results:
Dim xd As XDocument = _
<?xml version="1.0" encoding="utf-8"?>
<root>
[code].....
The above result returns both 'element' nodes however it should only return the first where element/subelement@id=1/subsubelement@id=3 However if results.Ancestors. is used it returns the correct 'subelement' and if that line is not included it returns a single 'subsubelement' whih is also correct I don't understand why when mvoing to the 'element' it returns both (I realise both have a subelement with id=1 but I thought each further query would filter out the presvious results)?
.net - LINQ C# Query In VB - Getting An Error
Feb 22, 2012I have a List of Price Objects (Price contains Date, High, Low) and am trying to extract monthly averages via LINQ. I have this working in C# but we have a few legacy applications that need it in VB.Net and I can't quite seem to figure out the conversion. I've even tried breaking it into two queries to no avail.
[Code]...
.net - Linq Query If Statement?
Jun 24, 2011Ok im trying to do a if statement in Linq and was wondering if it was possible to do something like:
Dim loadFriends = From p In db.UserRelationships Where p.aspnet_User.UserName = User.Identity.Name _
Or p.aspnet_User1.UserName = User.Identity.Name And p.Type = 1 _
Select New With {if p.aspnet_user1.user = "a certan username" then .username = _
p.aspnet_user.username else .username = p.aspnet_user1.Username}
[Code]...
.net - Linq Query To List?
Sep 2, 2011Dim query = From o In myContainer.MyObjects Select o.MyStringProperty Distinct
Dim myProperties As List(Of String) = query.ToList????? 'no way!!!'
"query" type is IEnumerable(Of String)
I tried to use the query directly as a DataSource of a (infragistic) combobox, but it throws me NullReferenceException, so I decided to convert it to a listof strings, to be a more "classical" datasource.
Dim values As List(Of String) = query.AsQueryable().ToList()
does not work either: Value of type 'System.Collections.Generic.List(Of System.Linq.IQueryable(Of String))' cannot be converted to 'System.Collections.Generic.List(Of String)'.