Try this:

    context.People.AddOrUpdate(p =&gt; new { p.FirstName, p.LastName }, people);

If you got `Only primitive types or enumeration types are supported in this context.` because of using navigation property - consider adding foreign key property directly to the entity (maybe only with getter) and use it as *Ladislav Mrnka* proposed.

I&#39;m studying C# and I wonder what the point and benefit of overriding `ToString` might be, as shown in the example below.

Could this be done in some simpler way, using a common method without the override?

    public string GetToStringItemsHeadings
    {
        get { return string.Format(&quot;{0,-20} {1, -20}&quot;, &quot;Office Email&quot;, &quot;Private Email&quot;); }
    }
    
    
    public override string ToString()
    {
        string strOut = string.Format(&quot;{0,-20} {1, -20}&quot;, m_work, m_personal);
        return strOut;
    }

Why / when would it be appropriate to override ToString?

I understand that ExternalFiles is to be used on API 8 and up and getExternalStorageDirectory is for 7 and down. However I am a little confused between the use. For example I wanted to check that a folder that exists and previously you would use something like:

    File ChildFolder = new File(Environment.getExternalStorageDirectory() + &quot;/ParentFolder/Child&quot;);

However every example I see says to use getExternalFilesDir (null), File.ext. Since I am above API 8 I want to use this method but how do I just check for a folder? I will check for a files existence at another point but for now just want to see if the folders exist??


Difference between getExternalFilesDir and getExternalStorageDirectory()

I am trying to seed a development database with some test data.

I have used `context.People.AddOrUpdate(p =&gt; p.Id, people));` with much success.

I have another table that I need to seed, in which I would not know the primary key.


For example, I would want to AddOrUpdate based on the First and Last names matching.

I am unsure how to write the Expression correctly.


    context.People.AddOrUpdate(p =&gt; p.FirstName &amp;&amp; p.LastName, people);

is obviously incorrect, but I hope it conveys the solution I am looking for.

How to seed data with AddOrUpdate with a complex key in EF 4.3

I am trying to seed a development database with some test data.
I have used <code>context.People.AddOrUpdate(p => p.Id, people));</code> with much success.
I have another table that I need to seed, in which I would not know the primary key.
For example, I would want to AddOrUpdate based on the First and Last names matching.
I am unsure how to write the Expression correctly.
<pre><code class="hljs language-css">context.People.AddOrUpdate(p => p.FirstName &#x26;&#x26; p.LastName, people);
</code></pre>
is obviously incorrect, but I hope it conveys the solution I am looking for.

I&#39;ve seen several suggestions, that you can add hyperlink to WPF application through `Hyperlink` control.

Here&#39;s how I&#39;m trying to use it in my code: 

	&lt;Window
			xmlns=&quot;http://schemas.microsoft.com/winfx/2006/xaml/presentation&quot;
			xmlns:x=&quot;http://schemas.microsoft.com/winfx/2006/xaml&quot;
			xmlns:d=&quot;http://schemas.microsoft.com/expression/blend/2008&quot; 
			xmlns:mc=&quot;http://schemas.openxmlformats.org/markup-compatibility/2006&quot; 
			mc:Ignorable=&quot;d&quot; 
			x:Class=&quot;BookmarkWizV2.InfoPanels.Windows.UrlProperties&quot;
			Title=&quot;UrlProperties&quot; Height=&quot;754&quot; Width=&quot;576&quot;&gt;
		&lt;Grid&gt;
			&lt;Grid.RowDefinitions&gt;
				&lt;RowDefinition&gt;&lt;/RowDefinition&gt;
				&lt;RowDefinition Height=&quot;40&quot;/&gt;
			&lt;/Grid.RowDefinitions&gt;
			&lt;Grid&gt;
				&lt;ScrollViewer ScrollViewer.VerticalScrollBarVisibility=&quot;Auto&quot; Grid.RowSpan=&quot;2&quot;&gt;
					&lt;StackPanel &gt;
						&lt;DockPanel LastChildFill=&quot;True&quot; Margin=&quot;0,5&quot;&gt;
							&lt;TextBlock Text=&quot;Url:&quot; Margin=&quot;5&quot; 
								DockPanel.Dock=&quot;Left&quot; VerticalAlignment=&quot;Center&quot;/&gt;
							&lt;TextBox Width=&quot;Auto&quot;&gt;
								&lt;Hyperlink NavigateUri=&quot;http://www.google.co.in&quot;&gt;
										Click here
								&lt;/Hyperlink&gt;   
							&lt;/TextBox&gt;						
						&lt;/DockPanel &gt;
					&lt;/StackPanel&gt;
				&lt;/ScrollViewer&gt;        
			&lt;/Grid&gt;
			&lt;StackPanel HorizontalAlignment=&quot;Right&quot; Orientation=&quot;Horizontal&quot; Margin=&quot;0,7,2,7&quot; Grid.Row=&quot;1&quot; &gt;
				&lt;Button Margin=&quot;0,0,10,0&quot;&gt;
					&lt;TextBlock Text=&quot;Accept&quot; Margin=&quot;15,3&quot; /&gt;
				&lt;/Button&gt;
				&lt;Button Margin=&quot;0,0,10,0&quot;&gt;
					&lt;TextBlock Text=&quot;Cancel&quot; Margin=&quot;15,3&quot; /&gt;
				&lt;/Button&gt;
			&lt;/StackPanel&gt;
		&lt;/Grid&gt;
	&lt;/Window&gt;

I&#39;m getting following error:

&gt; Property &#39;Text&#39; does not support values of type &#39;Hyperlink&#39;.	

What am I doing wrong?

Example using Hyperlink in WPF

I do not have a lot of experience with C#, yet I am used of working with associative arrays in PHP.

I see that in C# the List class and the Array are available, but I would like to associate some string keys.

What is the easiest way to handle this?

Thx!

What is the easiest way to handle associative array in c#?

When would you use the attribute `ChildActionOnly`? What is a `ChildAction` and in what circumstance would you want restrict an action using this attribute?

Using ChildActionOnly in MVC

In C#, say I have a class called `Note` with three string member variables.

```C#
public class Note
{
    public string Title;
    public string Author;
    public string Text;
}
```

And I have a list of type `Note`:

```C#
List&lt;Note&gt; Notes = new List&lt;Note&gt;();
```

What would be the cleanest way to get a list of all distinct values in the Author column?  

I could iterate through the list and add all values that aren&#39;t duplicates to another list of strings, but this seems dirty and inefficient.  I have a feeling there&#39;s some magical Linq construction that&#39;ll do this in one line, but I haven&#39;t been able to come up with anything.

Get a list of distinct values in List

How can I get all constants of any type using reflection?

How can I  get all constants of a type by reflection?

For some reason, my migrations appear to have been jumbled/corrupted/whatever.  I&#39;m at the point where I just want to start over, so is there a way to completely undo all migrations, erase the history, and delete the migration code, so I&#39;m back to square one?

e.g.) `PM&gt; Disable-Migrations` or `Rollback-Migrations`

I don&#39;t want to &quot;update&quot; to an original migration step (i.e. something like an `InitialSchema` target) because I can&#39;t find it anymore.



Entity Framework - Start Over - Undo/Rollback All Migrations

I have an ASP.NET MVC3 project that uses Entity Framework 4.3 with the code-first approach. I use Migrations to keep the database up-to-date.

The project is under source-control and I have a number of branches. What I just realized is that there will be a problem when I want to merge one of my branches into the master. Since I have created migration-files in both branches, there will be overlapping migrations when I merge, which will probably cause conflicts.

Is there a good way to manage Migrations in a project with multiple branches?

**Update**

One way would be to merge, then delete all migration-files created while the branches were separate, and then create one new migration file that holds all changes from the time the branch was created until it was merged back in. This would work for the dev-environment where you can dump the database and re-build it with all the migration-files. The problem then would be the live-environment. Since you couldn&#39;t roll back to the time the branch was created without the risk of loosing data, there will be a conflict when you try to use your new migration-file to update the live database.

How to manage Migrations in a project with multiple branches?

I am using Entity Framework 4.3 and using Code Fist.

I have a class 

    public class User
    {
       public int UserId{get;set;}
       public string UserName{get;set;}
    }

How do I tell Entity Framework that UserName has to be unique when creating database table?
I would prefer to use data anotations instead of configuration file if possible.


Entity Framework code first unique column

I just install EF 4.3 and trying to upgrade my project with migration. however I am getting issues with trying to execute `add-migration initial` to my project via Package Manager console. 

It is throwing any exception now `No connection string named &#39;MyApplicationEntities&#39; could be found in the application config file.` 

Now my config has it all 

    
    &lt;connectionStrings&gt;
    &lt;add name=&quot;MyApplicationEntities&quot; 
         connectionString=&quot;metadata=res://*/DataModel.csdl|res://*/DataModel.ssdl|res://*/DataModel.msl;provider=System.Data.SqlClient;provider connection string=&amp;quot;data source=localhost;initial catalog=MyApplicationEntitiesDB;integrated security=True;multipleactiveresultsets=True;App=EntityFramework&amp;quot;&quot; 
         providerName=&quot;System.Data.EntityClient&quot; /&gt;
  &lt;/connectionStrings&gt;

I am not sure what is the issue is it a bug in EF 4.3 or there is something I am not doing right. 



I thought [this post][1] has solved the issue but not quite.

Anyone got an answer. 

Appreciate Sanj. 


  [1]: https://stackoverflow.com/questions/7493337/entity-sqlce-cant-find-connection-string-in-app-config-file

No connection string named &#39;MyApplicationEntities&#39; could be found in the application config file

My impression to date has been that a `DbContext` is meant to represent your database, and thus, if your application uses one database, you&#39;d want only one `DbContext`.

However, some colleagues want to break functional areas out into separate `DbContext` classes.

I believe this comes from a good place -- a desire to keep the code cleaner -- but it seems volatile. My gut&#39;s telling me it&#39;s a bad idea, but unfortunately, my gut feeling is not a sufficient condition for a design decision.

So I&#39;m looking for:

A) concrete examples of why this might be a bad idea;

B) assurances that this will all work out just fine.

Entity Framework: One Database, Multiple DbContexts. Is this a bad idea?

I have a rather big program, where I use functions from the `random` module in different files. I would like to be able to set the random seed once, at one place, to make the program always return the same results. Can that even be achieved in `python`?

set random seed programwide in python

This is my code to generate random numbers using a seed as an argument:

    double randomGenerator(long seed) {
        Random generator = new Random(seed);
        double num = generator.nextDouble() * (0.5);

        return num;
    }

Every time I give a seed and try to generate 100 numbers, they all are the same.  
How can I fix this?


Java random numbers using a seed

I want to populate a new feature with dummy data, but don&#39;t want to use the db/seeds.rb file as it already has seeds other data irrelevant for this feature.

To run the default `seeds.rb` file, you run the command `rake db:seed`. 

**If I create a file in the `db` directory called `seeds_feature_x.rb`, what would the rake command look like to run (only) that file?**

Adding a custom seed file

I&#39;m currently trying to seed my users table. If I try it like this with 2 rows, it fails. It works fine if I just use a single array instead of the 2 arrays inside the $users array to create some fake data.

What am I doing wrong, what is the proper way to do this?

    class UserTableSeeder extends Seeder {

        public function run()
        {
            DB::table(&#39;users&#39;)-&gt;delete();
    
            $users = [
                [&#39;id&#39; =&gt; 1, &#39;name&#39; =&gt; &#39;Stephan de Vries&#39;, &#39;username&#39; =&gt; &#39;stephan&#39;, &#39;email&#39; =&gt; &#39;stephan-v@gmail.com&#39;, &#39;password&#39; =&gt; bcrypt(&#39;carrotz124&#39;)],
                [&#39;id&#39; =&gt; 2, &#39;name&#39; =&gt; &#39;John doe&#39;, &#39;username&#39; =&gt; &#39;johnny&#39;, &#39;email&#39; =&gt; &#39;johndoe@gmail.com&#39;, &#39;password&#39; =&gt; bcrypt(&#39;carrotz1243&#39;)],
            ];

            User::create($users);
        }

    }

*****

Seed multiple rows at once laravel 5

I&#39;m just looking into using EF migrations for our project, and in particular for performing schema changes in production between releases. 

I have seen mentioned that there is an API to perform these migrations at run-time using the `DbMigration` class, but I can&#39;t find any specific examples. 

Ideally, I would want one `DbMigration` file for every database change, and for those changes to be applied automatically on application start up from the current version up to the latest version.

Using Entity Framework (code first) migrations in production

I&#39;ve mucked up my migrations, I used `IgnoreChanges` on the initial migration, but now I want to delete all my migrations and start with an initial migration with all of the logic.

When I delete the migrations in the folder and try and `Add-Migration` it doesn&#39;t generate a full file (it&#39;s empty - because I haven&#39;t made any changes since my last, but now deleted, migration).

Is there any *Disable-Migrations* command, so I can rerun `Enable-Migrations`?

Reset Entity-Framework Migrations

This looks like a really common task, but I can&#39;t find an easy way to do it. 

I want to undo the last applied migration. I would have expected a simple command, like 

    PM&gt; Update-Database -TargetMigration:&quot;-1&quot;

Instead, all I can come up with is:

    PM&gt; Get-Migrations

    Retrieving migrations that have been applied to the target database.
    201208012131302_Add-SystemCategory
    201207311827468_CategoryIdIsLong
    201207232247409_AutomaticMigration
    201207211340509_AutomaticMigration
    201207200025294_InitialCreate

    PM&gt; Update-Database -TargetMigration:&quot;CategoryIdIsLong&quot;

(At least I can use just the name, skipping the timestamp...)

Is there an easier way?

Content Type	Original Author	Original Content on Stackoverflow
Question	Keith Sirmons	View Question on Stackoverflow
Solution 1 - C#	Ladislav Mrnka	View Answer on Stackoverflow
Solution 2 - C#	lukyer	View Answer on Stackoverflow

How to seed data with AddOrUpdate with a complex key in EF 4.3

C# Problem Overview

C# Solutions

Solution 1 - C#

Solution 2 - C#

Difference between getExternalFilesDir and getExternalStorageDirectory()

Why / when would it be appropriate to override ToString?

Attributions