I would guess that EF doesn&#39;t support the overload of StartsWith that takes a StringComparison parameter.

It should support **StartsWith**, **EndsWith** and **Contains**, so maybe you can try:

    dp.LastName.StartsWith(searchTerm)

or:

    dp.LastName.ToLower().StartsWith(searchTerm)

and then make sure that `searchTerm` is also lowercase.

What is a Proxy Class in C++? Why it is created and where it is useful?

What is Proxy Class in C++

I am looking for an alternative to the visitor pattern. Let me just focus on a couple of pertinent aspects of the pattern, while skipping over unimportant details. I&#39;ll use a Shape example (sorry!):

1. You have a hierarchy of objects that implement the IShape interface
2. You have a number of global operations that are to be performed on all objects in the hierarchy, e.g. Draw, WriteToXml etc...
3. It is tempting to dive straight in and add a Draw() and WriteToXml() method to the IShape interface. This is not necessarily a good thing - whenever you wish to add a new operation that is to be performed on all shapes, each IShape-derived class must be changed
4. Implementing a visitor for each operation i.e. a Draw visitor or a WirteToXml visitor encapsulates all the code for that operation in one class. Adding a new operation is then a matter of creating a new visitor class that performs the operation on all types of IShape
5. When you need to add a new IShape-derived class, you essentially have the same problem as you did in 3 - all visitor classes must be changed to add a method to handle the new IShape-derived type

Most places where you read about the visitor pattern state that point 5 is pretty much the main criteria for the pattern to work and I totally agree. If the number of IShape-derived classes is fixed, then this can be a quite elegant approach.

So, the problem is when a new IShape-derived class is added - each visitor implementation needs to add a new method to handle that class. This is, at best, unpleasant and, at worst, not possible and shows that this pattern is not really designed to cope with such changes.

So, the question is has anybody come across alterative approaches to handling this situation?


Alternative to the visitor pattern?

I&#39;m trying to build a search page using LINQ to Entities, but the following code is giving me a runtime error about l.t.e. not recognising &#39;Boolean StartsWith().  The code compiles just fine.  How can I work around this better than shipping the StartsWith filtering out to a stored proc?

        return from dp in dents.DirectoryPersonEntrySet
               where
                   ((dp.LastName.StartsWith(searchTerm, StringComparison.CurrentCultureIgnoreCase)) ||
                    (dp.Department.StartsWith(searchTerm, StringComparison.CurrentCultureIgnoreCase)) ||
                    dp.Extension.StartsWith(searchTerm, StringComparison.CurrentCultureIgnoreCase))
               select dp;



Problem with LINQ to Entities and String.StartsWith

I'm trying to build a search page using LINQ to Entities, but the following code is giving me a runtime error about l.t.e. not recognising 'Boolean StartsWith(). The code compiles just fine. How can I work around this better than shipping the StartsWith filtering out to a stored proc?
<pre><code class="hljs language-csharp"> return from dp in dents.DirectoryPersonEntrySet
 where
 ((dp.LastName.StartsWith(searchTerm, StringComparison.CurrentCultureIgnoreCase)) ||
 (dp.Department.StartsWith(searchTerm, StringComparison.CurrentCultureIgnoreCase)) ||
 dp.Extension.StartsWith(searchTerm, StringComparison.CurrentCultureIgnoreCase))
 select dp;
</code></pre>

What do I need to do to make a [Windows Forms][1] application to be able to run in the System Tray?

Not an application that can be minimized to the tray, but an application that will be only exist in the tray, with nothing more than 
  - an icon
  - a tool tip, and 
  - a &quot;*right click*&quot; menu.

  [1]: https://docs.microsoft.com/en-us/dotnet/desktop/winforms/overview/?view=netdesktop-5.0


How can I make a .NET Windows Forms application that only runs in the System Tray?

I have a `byte[]` array that is loaded from a file that I happen to known contains [UTF-8][1].

In some debugging code, I need to convert it to a string. Is there a one-liner that will do this?

Under the covers it should be just an allocation and a *memcopy*, so even if it is not implemented, it should be possible.

  [1]: http://en.wikipedia.org/wiki/UTF-8




How to convert UTF-8 byte[] to string

I&#39;m trying to compare a time stamp from an incoming request to a database stored value. SQL Server of course keeps some precision of milliseconds on the time, and when read into a .NET DateTime, it includes those milliseconds. The incoming request to the system, however, does not offer that precision, so I need to simply drop the milliseconds.

I feel like I&#39;m missing something obvious, but I haven&#39;t found an elegant way to do it (C#).

How to truncate milliseconds off of a .NET DateTime

I have 60k items that need to be checked against a 20k lookup list. Is there a collection object (like `List`, `HashTable`) that provides an exceptionly fast `Contains()` method? Or will I have to write my own? In otherwords, is the default `Contains()` method just scan each item or does it use a better search algorithm.

    foreach (Record item in LargeCollection)
    {
        if (LookupCollection.Contains(item.Key))
        {
           // Do something
        }
    }

**Note**. The lookup list is already sorted.

What .NET collection provides the fastest search

I&#39;m currently having some assembly binding problems on our development server. I want to investigate the problem a bit further with Fusion Log Viewer. Since there is no Visual Studio installed on the machine, I copied FUSLOGVW.EXE to a local folder and started it there.

Is this supposed to work or does it need something else? I don&#39;t get the impression the application is logging any failures (and yes I have the settings right).

using FUSLOGVW.EXE on a machine with no Visual Studio installed

I have the following item set from an XML:

    id           category
    
    5            1
    5            3
    5            4
    5            3
    5            3

I need a distinct list of these items:

    5            1
    5            3
    5            4

How can I distinct for Category AND Id too in LINQ?


LINQ: Distinct values

I usually create a sequence from a single value using array syntax, like this:

	IEnumerable&lt;string&gt; sequence = new string[] { &quot;abc&quot; };
	
Or using a new List&lt;T&gt;. I&#39;d like to hear if anyone has a more expressive way to do the same thing.


Favorite way to create an new IEnumerable&lt;T&gt; sequence from a single value?

I&#39;ve searched around and haven&#39;t really found a clear answer as to when you&#39;d want to use `.First` and when you&#39;d want to use `.FirstOrDefault` with LINQ.

 - When would you want to use `.First`? Only when you&#39;d want to catch the exception if no results where returned?

        var result = List.Where(x =&gt; x == &quot;foo&quot;).First();

 - And when would you want to use `.FirstOrDefault`? When you&#39;d always want the default type if no result?

        var result = List.Where(x =&gt; x == &quot;foo&quot;).FirstOrDefault();

 - And for that matter, what about Take?

        var result = List.Where(x =&gt; x == &quot;foo&quot;).Take(1);





When to use .First and when to use .FirstOrDefault with LINQ?

Is there a built-in way to convert `IEnumerator&lt;T&gt;` to `IEnumerable&lt;T&gt;`?


Is there a built-in way to convert IEnumerator to IEnumerable

I am a LINQ newbie trying to use it to acheive the following:


I have a list of ints:-

    List&lt;int&gt; intList = new List&lt;int&gt;(new int[]{1,2,3,3,2,1});

Now, I want to compare the sum of the first three elements [index range 0-2] with the last three [index range 3-5] using LINQ. I tried the LINQ Select and Take extension methods as well as the SelectMany method, but I cannot figure out how to say something like 

    (from p in intList  
    where p in  Take contiguous elements of intList from index x to x+n  
    select p).sum()

I looked at the Contains extension method too, but that doesn&#39;t see to get me what I want. Any suggestions? Thanks.

How to select values within a provided index range from a List using LINQ

For several reasons that I don&#39;t have the liberty to talk about, we are defining a view on our Sql Server 2005 database like so:

    CREATE VIEW [dbo].[MeterProvingStatisticsPoint]
    AS
    SELECT
    	CAST(0 AS BIGINT) AS &#39;RowNumber&#39;,
    	CAST(0 AS BIGINT) AS &#39;ProverTicketId&#39;,
    	CAST(0 AS INT) AS &#39;ReportNumber&#39;,
    	GETDATE() AS &#39;CompletedDateTime&#39;,
    	CAST(1.1 AS float) AS &#39;MeterFactor&#39;,
    	CAST(1.1 AS float) AS &#39;Density&#39;,
    	CAST(1.1 AS float) AS &#39;FlowRate&#39;,
    	CAST(1.1 AS float) AS &#39;Average&#39;,
    	CAST(1.1 AS float) AS &#39;StandardDeviation&#39;,
    	CAST(1.1 AS float) AS &#39;MeanPlus2XStandardDeviation&#39;,
    	CAST(1.1 AS float) AS &#39;MeanMinus2XStandardDeviation&#39;
    WHERE 0 = 1

The idea is that the Entity Framework will create an entity based on this query, which it does, but it generates it with an error that states the following:

&gt;Warning 6002: The table/view &#39;Keystone_Local.dbo.MeterProvingStatisticsPoint&#39; does not have a primary key defined. The key has been inferred and the definition was created as a read-only table/view.

And it decides that the CompletedDateTime field will be this entity primary key. 

We are using EdmGen to generate the model. Is there a way not to have the entity framework include any field of this view as a primary key?

Entity Framework and SQL Server View

&gt;&gt;&gt;Error 3007: Problem in Mapping Fragments starting at lines 186, 205: Non-Primary-Key column(s) [WheelID] are being mapped in both fragments to different conceptual side properties - data inconsistency is possible because the corresponding conceptual side properties can be independently modified.

I found several places on the web describing this error, but I simply don&#39;t understand them. (confused smiley goes here)

[One][1]  
[Two][2]  
[Three][3]  
[Four][4]  

There is something pretty fundamental here, I must be missing. Can you explain it, so that I understand it? Maybe using my real life example below?

[![alt text][5]][5]
&lt;!-- source: http://i39.tinypic.com/2hppnoo.jpg --&gt;

Foreign key 1:N Wheels.Id -&gt; Slices.WheelId

I add them to entity framework, and WheelId is not visible in the Slices-entity.

[![alt text][6]][6]
&lt;!-- source: http://i43.tinypic.com/287hq87.jpg --&gt;

Doing some workaround (deleting the relationship from the db before adding tables to EF - then re-creating it and updating EF) I managed to get the WheelId to stay in Slices, but then I get the error mentioned at the top.


  [1]: http://social.msdn.microsoft.com/Forums/en-US/adodotnetentityframework/thread/2823634f-9dd1-4547-93b5-17bb8a882ac2
  [2]: http://marko.unite.si/post/2008/11/19/Problem-in-Mapping-Fragments-in-Visual-Studio-2008s-Entity-Model-designer.aspx
  [3]: http://techiethings.blogspot.com/2009/03/entity-framework-error-3007.html
  [4]: http://earthli.com/news/view_article.php?id=2167
  [5]: https://i.stack.imgur.com/cgBmc.jpg
  [6]: https://i.stack.imgur.com/bZKpx.jpg
  [7]: http://i43.tinypic.com/2concw1.jpg

Entity framework - &quot;Problem in mapping fragments&quot;-error. Help me understand the explanations of this error

We&#39;re trying to implement the &quot;LIKE&quot; operator in Entity Framework for our entities with string fields, but it doesn&#39;t appear to be supported.  Has anyone else tried to do something like this?

This [blog post][1] summarizes the issue we&#39;re having.  We could use contains, but that only matches the most trivial case for LIKE.  Combining contains, startswith, endswith, and indexof gets us there, but requires a translation between standard wildcards and Linq to Entities code.


  [1]: http://th2tran.blogspot.com/2009/06/linq-to-entities-does-not-recognize.html

Like Operator in Entity Framework?

This code:

    using (EntityConnection conn = new EntityConnection(&quot;name=ELSCommonEntities&quot;))
    {
      conn.Open();
    }

Gives me the following error:

&lt;!-- language: lang-none --&gt;

    Test method ELS.Service.Business.IntegrationTest.Base.ServiceBaseIntegrationTest.StartLoggingTestMethod threw exception:  System.Data.MetadataException: Unable to load the specified metadata resource..

With the following stack trace:

&lt;!-- language: lang-none --&gt;

    System.Data.Metadata.Edm.MetadataArtifactLoaderCompositeResource.LoadResources(String assemblyName, String resourceName, ICollection`1 uriRegistry, MetadataArtifactAssemblyResolver resolver)
    System.Data.Metadata.Edm.MetadataArtifactLoaderCompositeResource.CreateResourceLoader(String path, ExtensionCheck extensionCheck, String validExtension, ICollection`1 uriRegistry, MetadataArtifactAssemblyResolver resolver)
    System.Data.Metadata.Edm.MetadataArtifactLoader.Create(String path, ExtensionCheck extensionCheck, String validExtension, ICollection`1 uriRegistry, MetadataArtifactAssemblyResolver resolver)
    System.Data.EntityClient.EntityConnection.SplitPaths(String paths)
    System.Data.EntityClient.EntityConnection.GetMetadataWorkspace(Boolean initializeAllCollections)
    System.Data.EntityClient.EntityConnection.InitializeMetadata(DbConnection newConnection, DbConnection originalConnection, Boolean closeOriginalConnectionOnFailure)
    System.Data.EntityClient.EntityConnection.Open()
    ELS.Service.Business.Base.ServiceBase.StartLogging(String userWindowsLogon) in C:\C-TOM\ELS-RELEASE1\ELS.Service.Business\Base\ServiceBase.cs: line 98
    ELS.Service.Business.IntegrationTest.Base.ServiceBaseIntegrationTest.StartLoggingTestMethod() in C:\C-TOM\ELS-RELEASE1\ELS.Service.Business.IntegrationTest\Base\ServiceBaseIntegrationTest.cs: line 65

However, this code which uses the same connection string:

    using (ELSCommonEntities db = new ELSCommonEntities())
    {
        var res = from c in db.Logging
                  select c;

        int i = res.Count();
    }


Does not give an error. 

The connection string is:

    &lt;add name=&quot;ELSCommonEntities&quot; connectionString=&quot;metadata=res://*/Common.CommonModel.csdl|res://*/Common.CommonModel.ssdl|res://*/Common.CommonModel.msl;provider=System.Data.SqlClient;provider connection string=&amp;quot;Data Source=localhost;Initial Catalog=els5_demo;Integrated Security=True;MultipleActiveResultSets=True&amp;quot;&quot; providerName=&quot;System.Data.EntityClient&quot; /&gt;

I have also opened up the dll in reflector and the metadata looks ok.


MetadataException when using Entity Framework Entity Connection

I have developed an application using [Entity Framework][1], SQL Server 2000, Visual&amp;nbsp;Studio&amp;nbsp;2008 and Enterprise Library.

It works absolutely fine locally, but when I deploy the project to our test environment, I am getting the following error:

&gt; Unable to load one or more of the requested types. Retrieve the LoaderExceptions property for more information
&gt;
&gt; Stack trace: at System.Reflection.Module._GetTypesInternal(StackCrawlMark&amp; stackMark)
&gt;
&gt; at System.Reflection.Assembly.GetTypes()
&gt;
&gt; at System.Data.Metadata.Edm.ObjectItemCollection.AssemblyCacheEntry.LoadTypesFromAssembly(LoadingContext context)
&gt;
&gt; at System.Data.Metadata.Edm.ObjectItemCollection.AssemblyCacheEntry.InternalLoadAssemblyFromCache(LoadingContext context)
&gt;
&gt; at System.Data.Metadata.Edm.ObjectItemCollection.AssemblyCacheEntry.LoadAssemblyFromCache(Assembly assembly, Boolean loadReferencedAssemblies, Dictionary`2 knownAssemblies, Dictionary`2&amp; typesInLoading, List`1&amp; errors)
&gt;
&gt; at System.Data.Metadata.Edm.ObjectItemCollection.LoadAssemblyFromCache(ObjectItemCollection objectItemCollection, Assembly assembly, Boolean loadReferencedAssemblies)
&gt;
&gt; at System.Data.Metadata.Edm.ObjectItemCollection.LoadAssemblyForType(Type type)
&gt;
&gt; at System.Data.Metadata.Edm.MetadataWorkspace.LoadAssemblyForType(Type type, Assembly callingAssembly)
&gt;
&gt; at System.Data.Objects.ObjectContext.CreateQuery[T](String queryString, ObjectParameter[] parameters)

Entity Framework seems to have issue, any clue how to fix it?

  [1]: http://en.wikipedia.org/wiki/ADO.NET_Entity_Framework


Error message &#39;Unable to load one or more of the requested types. Retrieve the LoaderExceptions property for more information.&#39;

    var items = from c in contacts
                select new ListItem
                {
                    Value = c.ContactId, //Cannot implicitly convert type &#39;int&#39; (ContactId) to &#39;string&#39; (Value).
                    Text = c.Name
                };
    var items = from c in contacts
                select new ListItem
                {
                    Value = c.ContactId.ToString(), //Throws exception: ToString is not supported in linq to entities.
                    Text = c.Name
                };

Is there anyway I can achieve this?
Note, that in VB.NET there is no problem use the first snippet it works just great, VB is flexible, im unable to get used to C#&#39;s strictness!!!

Problem with converting int to string in Linq to entities

Please help.
I am trying to figure out how to use DATE or DATETIME for comparison in a linq query.

Example:
If I wanted all Employee names for those who started before today, I would do something like this in SQL:

    SELECT EmployeeNameColumn
    FROM EmployeeTable
    WHERE StartDateColumn.Date &lt;= GETDATE() //Today

But what about linq?

    DateTime startDT = //Today
    
    var EmployeeName =  
    from e in db.employee
    where e.StartDateColumn &lt;= startDT 

The above WHERE doesn&#39;t work: 
&gt;Exception Details: System.NotSupportedException: The specified type member &#39;Date&#39; is not supported in LINQ to Entities. Only initializers, entity members, and entity navigation properties are supported.

How do I perform Date Comparison in EF query?

I am using entities, C# and SQL Server to create an n-tier app. I am creating some base classes common to all my DAL components. In this base class, i want to handle the connection state of the ObjectContext base class inherited by entities object.

Compiling throws the following error:  
  

&gt; The type or namespace name &#39;Objects&#39;
&gt; does not exist in the namespace
&gt; &#39;System.Data&#39; (are you missing an
&gt; assembly reference?)

  

Also, the using statement System.Data.Objects doesn&#39;t resolve for the same reason. 

I tried adding the assembly as reference, but couldn&#39;t find it in the .NET tab of assembly references.

Any thoughts? Thanks!

The type or namespace name &#39;Objects&#39; does not exist in the namespace &#39;System.Data&#39;

I am having two date values, one already stored in the database and the other selected by the user using DatePicker. The use case is to search for a particular date from the database.

The value previously entered in the database always has time component of 12:00:00, where as the date entered from picker has different time component. 

I am interested in only the date components and would like to ignore the time component. 

What are the ways to do this comparison in C#?

Also, how to do this in LINQ?

UPDATE:
On LINQ to Entities, the following works fine.

    e =&gt; DateTime.Compare(e.FirstDate.Value, SecondDate) &gt;= 0

Content Type	Original Author	Original Content on Stackoverflow
Question	ProfK	View Question on Stackoverflow
Solution 1 - .Net	BengtBe	View Answer on Stackoverflow

Problem with LINQ to Entities and String.StartsWith

.Net Problem Overview

.Net Solutions

Solution 1 - .Net

Alternative to the visitor pattern?

What is Proxy Class in C++

Attributions