Using query syntax:

    from c in dbo.Companies
    join p in dbo.Persons on c.AccountCoordinatorPersonId equals p.PersonId
    join p2 in dbo.Persons on c.AccountManagerPersonId equals p2.PersonId
    select new
    {
        c.CompanyId,
        c.CompanyName,
        AccountCoordinator = p.FirstName + &#39; &#39; + p.Surname,
        AccountManager = p2.FirstName + &#39; &#39; + p2.Surname
    }

Using method chaining:

    dbo.Companies.Join(dbo.Persons, 
                       c =&gt; c.AccountCoordinatorPersonId,  
                       p =&gt; p.PersonId,  
                       (c, p) =&gt; new 
                       {  
                           Company = c,  
                           AccountCoordinator = p.FirstName + &#39; &#39; + p.Surname  
                       })
                 .Join(dbo.Persons,  
                       c =&gt; c.Company.AccountManagerPersonId,  
                       p2 =&gt; p2.PersonId,  
                       (c, p2) =&gt; new 
                       {  
                           c.Company.CompanyId,  
                           c.Company.CompanyName,  
                           c.AccountCoordinator,  
                           AccountManager = p2.FirstName + &#39; &#39; + p2.Surname 
                       });

I need to use boost::disjoint_sets, but [the documentation][1] is unclear to me. Can someone please explain what each template parameter means, and perhaps give a small example code for creating a disjoint_sets?

As per the request, I am using disjoint_sets to implement [Tarjan&#39;s off-line least common ancestors algorithm][2], i.e - the value type should be vertex_descriptor.


  [1]: http://www.boost.org/doc/libs/1_33_1/libs/disjoint_sets/disjoint_sets.html
  [2]: http://en.wikipedia.org/wiki/Tarjan&#39;s_off-line_least_common_ancestors_algorithm

Understanding boost::disjoint_sets

I have a UILabel, but how can I allow the user to select a portion of it&#39;s text. I don&#39;t want the user to be able to edit the text nor the label/textfield to have a border. 

Allow user to select text from UILabel to copy

I&#39;ve got the basics of LINQ-to-SQL down, but I&#39;ve been struggling trying to get JOINs to work properly.  I&#39;d like to know how to convert the following to LINQ-to-SQL (ideally using method chaining, as that is my preferred format).

    SELECT      c.CompanyId, c.CompanyName,
                p.FirstName + &#39; &#39; + p.LastName as AccountCoordinator,
                p2.FirstName + &#39; &#39; + p2.LastName as AccountManager
    FROM        dbo.Companies c
    INNER JOIN  dbo.Persons p
    ON          c.AccountCoordinatorPersonId = p.PersonId
    INNER JOIN  dbo.Persons p2
    ON          c.AccountManagerPersonId = p2.PersonId


How do I convert multiple inner joins in SQL to LINQ?

I've got the basics of LINQ-to-SQL down, but I've been struggling trying to get JOINs to work properly. I'd like to know how to convert the following to LINQ-to-SQL (ideally using method chaining, as that is my preferred format).
<pre><code class="hljs language-sql">SELECT c.CompanyId, c.CompanyName,
 p.FirstName + ' ' + p.LastName as AccountCoordinator,
 p2.FirstName + ' ' + p2.LastName as AccountManager
FROM dbo.Companies c
INNER JOIN dbo.Persons p
ON c.AccountCoordinatorPersonId = p.PersonId
INNER JOIN dbo.Persons p2
ON c.AccountManagerPersonId = p2.PersonId
</code></pre>

I need a regex that will only find matches where the entire string matches my query.

For instance if I do a search for movies with the name &quot;Red October&quot; I only want to match on that exact title (case insensitive) but not match titles like &quot;The Hunt For Red October&quot;. Not quite sure I know how to do this. Anyone know?

Thanks!

How do I match an entire string with a regex?

I have a C# class that I have inherited. I have successfully &quot;built&quot; the object. But I need to serialize the object to XML. Is there an easy way to do it?

It looks like the class has been set up for serialization, but I&#39;m not sure how to get the XML representation. My class definition looks like this:

    [System.CodeDom.Compiler.GeneratedCodeAttribute(&quot;xsd&quot;, &quot;4.0.30319.1&quot;)]
    [System.SerializableAttribute()]
    [System.Diagnostics.DebuggerStepThroughAttribute()]
    [System.ComponentModel.DesignerCategoryAttribute(&quot;code&quot;)]
    [System.Xml.Serialization.XmlTypeAttribute(AnonymousType = true, Namespace = &quot;http://www.domain.com/test&quot;)]
    [System.Xml.Serialization.XmlRootAttribute(Namespace = &quot;http://www.domain.com/test&quot;, IsNullable = false)]
    public partial class MyObject
    {
      ...
    }

Here is what I thought I could do, but it doesn&#39;t work:

    MyObject o = new MyObject();
    // Set o properties
    string xml = o.ToString();

How do I get the XML representation of this object?


Serialize an object to XML

What does it mean when you add the static keyword to a method?

    public static void doSomething(){
       //Well, do something!
    }

Can you add the `static` keyword to class? What would it mean then?

What&#39;s a &quot;static method&quot; in C#?

How can I calculate date difference between two dates in years?

For example: `(Datetime.Now.Today() - 11/03/2007)` in years.


Date difference in years using C#

In C# 4.0, we have `Task` in the *System.Threading.Tasks* namespace. What is the true difference between `Thread` and `Task`. I did some sample program(help taken from MSDN)  for my own sake of learning with 

    Parallel.Invoke 
    Parallel.For 
    Parallel.ForEach 

but have many doubts as the idea is not so clear. 

I have initially searched in Stackoverflow for a similar type of question but may be with this question title I was not able to get the same. If anyone knows about the same type of question being posted here earlier, kindly give the reference of the link.

What is the difference between task and thread?

In my application I am using Entity Framework. 

My Table

    -Article
    -period
    -startDate


I need records that match =&gt; `DateTime.Now &gt; startDate and (startDate + period) &gt; DateTime.Now`

I tried this code but its now working 

    Context.Article
        .Where(p =&gt; p.StartDate &lt; DateTime.Now)
        .Where(p =&gt; p.StartDate.AddDays(p.Period) &gt; DateTime.Now)

When I run my code the following exception occur
&gt;LINQ to Entities does not recognize the method &#39;System.DateTime AddDays(Double)&#39; method, and this method cannot be translated into a store expression.

Linq to EntityFramework DateTime

i have a list of writers.

    public class Writers{	
    	long WriterID { get;set; }
    }

Also I have two lists of type Article.

    public class Article{
    	long ArticleID { get; set; }
    	long WriterID { get; set; }
    	//and others	
    }

so the code i have is:
   

 

    List&lt;Article&gt; ArticleList = GetList(1);
    List&lt;Article&gt; AnotherArticleList = AnotherList(2);
    List&lt;Writers&gt; listWriters = GetAllForbiddenWriters();

	
I want to remove those records from `ArticleList`, `AnotherArticleList` where `WriterID` matches from `listWriters` `WriterID`. How to do this in LINQ?

            






Remove items of list from another lists with criteria

So I know that `Find()` is only a `List&lt;T&gt;` method, whereas `First()` is an extension for any `IEnumerable&lt;T&gt;`. I also know that `First()` will return the first element if no parameter is passed, whereas `Find()` will throw an exception. Lastly, I know that `First()` will throw an exception if the element is not found, whereas `Find()` will return the type&#39;s default value.

I hope that clears up confusion about what I&#39;m actually asking. This is a computer science question and deals with these methods at the computational level. I&#39;ve come to understand that `IEnumerable&lt;T&gt;` extensions do not always operate as one would expect under the hood. So here&#39;s the Q, and I mean from a &quot;close to the metal&quot; standpoint: What is the difference between `Find()` and `First()`?

Here&#39;s some code to provide basic assumptions to operate under for this question.

    var l = new List&lt;int&gt; { 1, 2, 3, 4, 5 };
    var x = l.First(i =&gt; i == 3);
    var y = l.Find(i =&gt; i == 3);
    
Is there any actual computational difference between how `First()` and `Find()` discover their values in the code above?

Note: Let us ignore things like `AsParallel()` and `AsQueryable()` for now.

C# Difference between First() and Find()

If all the items in a list have the same value, then I need to use that value, otherwise I need to use an “otherValue”. I can’t think of a simple and clear way of doing this. When the list is empty it should return the &quot;other&quot; value. 

See also [Neat way to write loop that has special logic for the first item in a collection.][1]


  [1]: https://stackoverflow.com/questions/4390232/neat-way-to-write-loop-that-has-special-logic-for-the-first-item-in-a-collection

How to check if all list items have the same value and return it, or return an “otherValue” if they don’t?

NHibernate eager loading can be done using `Fetch` and `FetchMany`, as described in [NHibernate Linq Eager Fetching](http://mikehadlow.blogspot.com/2010/08/nhibernate-linq-eager-fetching.html) on Mike Hadlow&#39;s blog.

What is the difference between these two methods and under what circumstance would each be used?

Fetch vs FetchMany in NHibernate Linq provider

We have a design with 150+ tables and in the .dbml layout has lines everywhere and it&#39;s hard to find individual tables.

Is there a way to search in the dbml layout instead of scrolling around trying to locate a table (Ctrl+F don&#39;t work), Running Visual Studio 2010 Ultimate?

Find (search for) table in DBML designer quickly?

**Given:**

A table named `TABLE_1` with the following columns:

 - `ID`
 - `ColumnA`
 - `ColumnB`
 - `ColumnC`

I have SQL query where `TABLE_1` joins on itself twice based off of `ColumnA`, `ColumnB`, `ColumnC`. The query might look something like this:

    Select t1.ID, t2.ID, t3.ID
      From TABLE_1 t1
      Left Join TABLE_1 t2 On
           t1.ColumnA = t2.ColumnA
       And t1.ColumnB = t2.ColumnB
       And t1.ColumnC = t2.ColumnC
      Left Join TABLE_1 t3 On
           t2.ColumnA = t3.ColumnA
       And t2.ColumnB = t3.ColumnB
       And t2.ColumnC = t3.ColumnC
    ... and query continues on etc.

**Problem:**

I need that Query to be rewritten in LINQ. I&#39;ve tried taking a stab at it:

    var query =
        from t1 in myTABLE1List // List&lt;TABLE_1&gt;
        join t2 in myTABLE1List
          on t1.ColumnA equals t2.ColumnA
          &amp;&amp; t1.ColumnB equals t2.ColumnA
        // ... and at this point intellisense is making it very obvious
        // I am doing something wrong :(

How do I write my query in LINQ? What am I doing wrong?

LINQ to SQL: Multiple joins ON multiple Columns. Is this possible?

What is difference between .edmx and .dbml file in linq?In VS 2008 which datasource is best choice where edmx or dbml?Any problem will arise using edmx file in VS 2008?Can i use edmx in VS-2008? 

What is difference between .edmx and .dbml file in linq?

I get this error when writing to the database:

&gt; A dependent property in a ReferentialConstraint is mapped to a
&gt; store-generated column. Column: &#39;PaymentId&#39;.

    public bool PayForItem(int terminalId, double paymentAmount, 
          eNums.MasterCategoryEnum  mastercategoryEnum, int CategoryId, int CategoryItemId)
        {

            using (var dbEntities = new DatabaseAccess.Schema.EntityModel())
            {
                int pinnumber = 0;
                long pinid = 1; //getPinId(terminalId,ref pinnumber) ;
                var payment = new DatabaseAccess.Schema.Payment();
                payment.CategoryId = CategoryId;
                payment.ItemCategoryId = CategoryItemId;
                payment.PaymentAmount = (decimal)paymentAmount;
                payment.TerminalId = terminalId;
                payment.PinId = pinid;

                payment.HSBCResponseCode = &quot;&quot;;
                payment.DateActivated = DateTime.Now;
                payment.PaymentString = &quot;Payment&quot;;
                payment.PromotionalOfferId = 1;
                payment.PaymentStatusId = (int)eNums.PaymentStatus.Paid;

                //payment.PaymentId = 1;

                dbEntities.AddToPayments(payment);
                dbEntities.SaveChanges();
            }
            return true;
        }

The schema is:

![enter image description here][1]


  [1]: http://i.stack.imgur.com/ygkYW.png

A dependent property in a ReferentialConstraint is mapped to a store-generated column

What is the difference between `.Select()` and `.Where()` in Entity Framework?
Eg 

    return ContextSet().Select(x=&gt; x.FirstName == &quot;John&quot;)

vs

    ContextSet().Where(x=&gt; x.FirstName == &quot;John&quot;)

When should I use `.Select` vs `.Where`?

Difference between Select and Where in Entity Framework

What&#39;s the difference between `INNER JOIN`, `LEFT JOIN`, `RIGHT JOIN` and `FULL JOIN` 
in ***MySQL***?


What&#39;s the difference between INNER JOIN, LEFT JOIN, RIGHT JOIN and FULL JOIN?

In trying to improve the speed of an immensely slow query (several _minutes_ on two tables with only ~50,000 rows each, on SQL Server 2008 if it matters), I narrowed down the problem to an `OR` in my inner join, as in:

    SELECT mt.ID, mt.ParentID, ot.MasterID
      FROM dbo.MainTable AS mt
      INNER JOIN dbo.OtherTable AS ot ON ot.ParentID = mt.ID
                                      OR ot.ID = mt.ParentID

I changed this to (what I hope is) an equivalent pair of left joins, shown here:

    SELECT mt.ID, mt.ParentID,
       CASE WHEN ot1.MasterID IS NOT NULL THEN
          ot1.MasterID ELSE
          ot2.MasterID END AS MasterID
      FROM dbo.MainTable AS mt
      LEFT JOIN dbo.OtherTable AS ot1 ON ot1.ParentID = mt.ID
      LEFT JOIN dbo.OtherTable AS ot2 ON ot2.ID = mt.ParentID
      WHERE ot1.MasterID IS NOT NULL OR ot2.MasterID IS NOT NULL

.. and the query now runs in about a second!

Is it generally a bad idea to put an `OR` in a join condition?  Or am I just unlucky somehow in the layout of my tables?

Is having an &#39;OR&#39; in an INNER JOIN condition a bad idea?

There are 2 tables, `spawnlist` and `npc`, and I need to delete data from `spawnlsit`.
`npc_templateid = n.idTemplate` is the only thing that &quot;connect&quot; the tables.
I have tried this script but it doesn&#39;t work.

I have tried this:

    DELETE s FROM spawnlist s
    INNER JOIN npc n ON s.npc_templateid = n.idTemplate
    WHERE (n.type = &quot;monster&quot;);



SQL DELETE with INNER JOIN

I have the below query which does not work. What am I doing wrong? Is this even possible?

    UPDATE ProductReviews AS R 
       INNER JOIN products AS P 
           ON R.pid = P.id 
    SET R.status = &#39;0&#39; 
    WHERE R.id = &#39;17190&#39; 
      AND P.shopkeeper = &#39;89137&#39;

SQL Server - inner join when updating

I have this cross-database query...

    SELECT
                `DM_Server`.`Jobs`.*,
                `DM_Server`.servers.Description AS server,
                digital_inventory.params,
                products.products_id,
                products.products_pdfupload,
                customers.customers_firstname,
                customers.customers_lastname
            FROM `DM_Server`.`Jobs`
            INNER JOIN `DM_Server`.servers ON servers.ServerID = Jobs.Jobs_ServerID
            JOIN `cpod_live`.`digital_inventory` ON digital_inventory.jobname = Jobs.Jobs_Name
            JOIN `cpod_live`.`products` ON products.products_pdfupload = CONCAT(digital_inventory.jobname, &quot;.pdf&quot;)
            JOIN `cpod_live`.`customers` ON customers.customers_id = products.cID
            ORDER BY `DM_Server`.`Jobs`.Jobs_StartTime DESC LIMIT 50

it runs fine until I make them `LEFT JOIN`s.  I thought that by not specifying a type of join it was assumed to be a `LEFT JOIN`.  Is this not the case?

Content Type	Original Author	Original Content on Stackoverflow
Question	Ed Sinek	View Question on Stackoverflow
Solution 1 - C#	Dave D	View Answer on Stackoverflow

How do I convert multiple inner joins in SQL to LINQ?

C# Problem Overview

C# Solutions

Solution 1 - C#

Allow user to select text from UILabel to copy

Understanding boost::disjoint_sets

Attributions