Value cannot be null. Parameter name: source

Question

This is probably the biggest waste of time problem I have spent hours on solving for a long time.

var db = new hublisherEntities();
establishment_brands est = new establishment_brands();

est.brand_id = 1;
est.establishment_id = 1;
est.price = collection["price"];
est.size = collection["size"];

db.establishment_brands.Add(est);
db.SaveChanges();

This gives me an error of

Value cannot be null. Parameter name: source

stacktrace of

[ArgumentNullException: Value cannot be null. Parameter name: source] System.Linq.Enumerable.Any(IEnumerable1 source, Func2 predicate) +4083335 System.Data.Entity.Internal.InternalContext.WrapUpdateException(UpdateException updateException) +87
System.Data.Entity.Internal.InternalContext.SaveChanges() +193
System.Data.Entity.Internal.LazyInternalContext.SaveChanges() +33
System.Data.Entity.DbContext.SaveChanges() +20 ... ...

I just want to add an entity to the table. The ORM is EF.

You might want to look into this question and its answers: stackoverflow.com/questions/3244336/… — Ville Salonen
– Ville Salonen, Commented Apr 29, 2013 at 14:29
Probably one of the entries in collectin has a null value:est.price = collection["price"]; est.size = collection["size"]; — MikeTWebb
– MikeTWebb, Commented Apr 29, 2013 at 14:29
@AshBurlaczenko oh, you think ? My schema looks like every column can be null. — danielovich
– danielovich, Commented Apr 29, 2013 at 14:34

Martin Mulder · Accepted Answer · 2023-10-31 20:55:25Z

311

Somewhere inside the DbContext is a value that is IEnumerable and is queried with Any() (or Where() or Select() or any other LINQ-method), but this value is null.

Find out if you put a query together (somewhere outside your example code) where you are using a LINQ-method, or that you used an IEnumerable as a parameter which is null.

edited Oct 31, 2023 at 20:55

answered Apr 29, 2013 at 14:32

Martin Mulder

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7 Comments

NibblyPig Over a year ago

This solved the problem to me, I suspect this is the solution to the OP as well even though the accepted answer is different.

Brian Lacy Over a year ago

The answer for me was that I hadn't yet initialized the List I was attempting to filter with .Where() -- it was still null.

Fer R Over a year ago

To avoid this kind of null errors you should either try put a default value in the IEnumerable properties or test them with Any()

ejcortes Over a year ago

This fixed the problem for me. Even though the accepted answer is different, I think the underlying cause is the same: non initialized collection. Maybe OP didn't include a connection string, or placed it on the wrong node.

gyousefi Over a year ago

This is the correct answer and related to the "Value cannot be null" error message. This error has nothing to do with connection string!

|

anaximander · Accepted Answer · 2013-04-29 14:43:24Z

52

I had this one a while back, and the answer isn't necessarily what you'd expect. This error message often crops up when your connection string is wrong.

At a guess, you'll need something like this:

<connectionStrings>
    <add name="hublisherEntities" connectionString="Data Source=localhost;Initial Catalog=hublisher;Integrated Security=True;" providerName="System.Data.SqlClient" />
</connectionStrings>
<entityFramework>
    <defaultConnectionFactory type="System.Data.Entity.Infrastructure.LocalDbConnectionFactory, EntityFramework">
        <parameters>
            <parameter value="Data Source=localhost;Initial Catalog=hublisher;Integrated Security=True" />
        </parameters>
    </defaultConnectionFactory>
</entityFramework>

What's happening is that it's looking for a data source in the wrong place; Entity Framework specifies it slightly differently. If you post your connection string and EF config then we can check.

answered Apr 29, 2013 at 14:43

anaximander

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4 Comments

jleach Over a year ago

In my case it was an incorrect conniption string in code, but still a connection string problem nonetheless.

Alan Macdonald Over a year ago

"isn't necessarily what you'd expect", you can say that one again

Deepak Yadav Over a year ago

Yes your problem may not be exactly same but it is a connection string problem, In my case : I was not setting the values of some configuration which I was using earlier and commented now in config file but trying to access them in code. Commented both it worked now.

mercury Over a year ago

I also restarted the docker img and it works

Sum None · Accepted Answer · 2019-04-13 21:22:06Z

27

I just got this exact error in .Net Core 2.2 Entity Framework because I didn't have the set; in my DbContext like so:

public DbSet<Account> Account { get; }

changed to:

public DbSet<Account> Account { get; set;}

However, it didn't show the exception until I tried to use a linq query with Where() and Select() as others had mentioned above.

I was trying to set the DbSet as read only. I'll keep trying...

answered Apr 13, 2019 at 21:22

Sum None

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2 Comments

Sunday Over a year ago

I just had this exact problem while trying to use my Assembly with Linqpad. Thanks for this, I could have wasted way more time. .Net Core 3.1/EF Core 3.1 here.

Benyamin Limanto Over a year ago

I just curious, if it's keyless entity, why we need to have set; hmm...

Ali Bdeir · Accepted Answer · 2021-05-14 15:29:35Z

14

I was calling Count on an instance of DbSet with a filter of null i.e.

dbSet.Count(null);

I found that passing null here was causing the error so I now call the parameter-less method if the filter is null:

 if (filter == null)
 {
     return dbSet.Count();
 }
 else
 {
     return dbSet.Count(filter);
 }

This sorted the issue for me. This may be an issue for any other methods on DbSet as well.

edited May 14, 2021 at 15:29

Ali Bdeir

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answered Aug 11, 2014 at 1:35

Guy Lowe

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Comments

Shadi Alnamrouti · Accepted Answer · 2021-01-03 12:47:30Z

7

Using the .Count() without checking for null is one strong reason for this error.

THE FIX:

if(someList != null & someList.Count()>0)
{
    //Now, put your hackable code here!
}

answered Jan 3, 2021 at 12:47

Shadi Alnamrouti

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Jared G. · Accepted Answer · 2018-08-29 12:51:16Z

6

My mistake was forgetting to add the .ThenInclude(s => s.SubChildEntities) onto the parent .Include(c => c.SubChildEntities) to the Controller action when attempting to call the SubChildEntities in the Razor view.

var <parent> = await _context.Parent
            .Include(c => c.<ChildEntities>)
            .ThenInclude(s => s.<SubChildEntities>)
            .SingleOrDefaultAsync(m => m.Id == id);

It should be noted that Visual Studio 2017 Community's IntelliSense doesn't pick up the SubChildEntities object in the lambda expression in the .ThenInclude(). It does successfully compile and execute though.

answered Aug 29, 2018 at 12:51

Jared G.

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johnny · Accepted Answer · 2013-10-11 13:45:51Z

5

just as an FYI, somebody may find it useful. I was chasing my tail for this error almost 2 days and was always thinking something big and looking for the classes that might be the issue and finally i found it very stupid issue and it was in my mark up (HTML) code in mypage.ascx. the issue was I have a <asp:EntityDataSource> and this has got a include property and I have some other tables listed here and mistakenly a table was there that has been delete from the database recently and I never noticed and it returning null with other entities. I just removed the stupid table from the include list and I am good to go. hope this can help somebody.

answered Oct 11, 2013 at 13:45

johnny

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Daniel de Zwaan · Accepted Answer · 2019-12-04 06:01:55Z

5

This exception will be returned if you attempt to count values in a null collection.

For example the below works when Errors is not null, however if Errors is null then the Value cannot be null. Parameter name: source exception occurs.

if (graphQLResponse.Errors.Count() > 0)

This exception can be avoided by checking for null instead.

if (graphQLResponse.Errors != null)

answered Dec 4, 2019 at 6:01

Daniel de Zwaan

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Comments

Franklin Tarter · Accepted Answer · 2018-05-30 16:56:07Z

In case anyone else ends up here with my issue with a DB First Entity Framework setup.

Long story short, I needed to overload the Entities constructor to accept a connection string, the reason being the ability to use Asp.Net Core dependency injection container pulling the connection string from appsettings.json, rather than magically getting it from the App.config file when calling the parameterless constructor.

I forgot to add the calls to initialize my DbSets in the new overload. So the auto-generated parameter-less constructor looked something like this:

    public MyEntities()
        : base("name=MyEntity")
    {
        Set1 = Set<MyDbSet1>();
        Set2 = Set<MyDbSet2>();
    }

And my new overload looked like this:

    public MyEntities(string connectionString)
        : base(connectionString)
    {
    }

The solution was to add those initializers that the auto-generated code takes care of, a simple missed step:

     public MyEntities(string connectionString)
        : base(connectionString)
    {
        Set1 = Set<MyDbSet1>();
        Set2 = Set<MyDbSet2>();
    }

This really threw me for a loop because some calls in our Respository that used the DbContext worked fine (the ones that didn't need those initialized DBSets), and the others throw the runtime error described in the OP.

KennethDale1 · Accepted Answer · 2018-08-09 15:39:51Z

2

Make sure you are injecting the repository into the service's constructor. That solved it for me. ::smacks forehead::

answered Aug 9, 2018 at 15:39

KennethDale1

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SharpC · Accepted Answer · 2019-12-16 14:17:17Z

2

Resolved with the following solution

Right click on the edmx file, select Open with, XML editor
Locate the entity in the edmx:StorageModels element
Remove the DefiningQuery entirely
Rename the store:Schema="dbo" to Schema="dbo" (if exists)
Remove the store:Name property

edited Dec 16, 2019 at 14:17

SharpC

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answered Dec 30, 2014 at 14:49

Ahmedk

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1 Comment

Vincent Buscarello Over a year ago

Schema="dbo" to Schema="dbo" -- what?

cunderpants · Accepted Answer · 2013-10-24 14:28:43Z

1

It could be as silly as in my case where savechanges was erroring bcoz the db did not have foreign keys and associations were added to EDM tables. I added foreign keys in the db and regenerated EDM for a fix.

The errors I was seeing are as follows: Case 1 -> when using DBContext for EDM Message=Value cannot be null. Parameter name: source at System.Linq.Enumerable.Any[TSource](IEnumerable1 source, Func2 predicate)

Case 2 -> when using ObjectContext for EDM Message=Unable to update the EntitySet 'Contact' because it has a DefiningQuery and no element exists in the element to support the current operation.

(Just wanted to throw it in there in case it helps someone).

edited Oct 24, 2013 at 14:28

answered Oct 24, 2013 at 14:18

cunderpants

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Muru Bakthavachalam · Accepted Answer · 2014-01-15 21:06:33Z

1

In MVC, View screen is calling method which is in Controller or Repository.cs and assigning return value to any control in CSHTML but that method is actually not implemented in .cs/controller, then CSHTML will throw the NULL parameter exception

answered Jan 15, 2014 at 21:06

Muru Bakthavachalam

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Kirsten · Accepted Answer · 2016-12-11 15:11:11Z

1

I got this error when I had an invalid Type for an entity property.

public Type ObjectType {get;set;}

When I removed the property the error stopped occurring.

answered Dec 11, 2016 at 15:11

Kirsten

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Sunil Jatolia · Accepted Answer · 2017-06-23 10:33:08Z

1

In my case, the problem popped up while configuring the web application on IIS, When the update command on any record was fired this error got generated.

It was a permission issue on App_Data which set to read-only. Right-click the folder, uncheck the Read-only checkbox and you are done. By the way, for testing purpose, I was using the localdb database which was in App_Data folder.

answered Jun 23, 2017 at 10:33

Sunil Jatolia

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Michael Rivera · Accepted Answer · 2019-03-14 03:25:02Z

1

I know this is a long way from the year 2013 of the question, but this symptom can show up if you don't have lazy loading enabled when migrating an ASP.NET 5 app to ASP.NET Core, and then trying to upgrade to Entity Framework Core 2.x (from EF 6). Entity Framework Core has moved lazy loading proxy support to a separate package, so you have to install it.

This is particularly true if all you have loaded is an Entity Framework Core Sql Server package (which turns on Entity Framework just fine).

After installing the proxies package, then, as the docs say, invoke .UseLazyLoadingProxies() on the DbContext options builder (in your Startup DI setup section, or wherever you configure your DbContext), and the navigational property that was throwing the above exception will stop throwing it, and will work as Entity Framework 6 used to.

answered Mar 14, 2019 at 3:25

Michael Rivera

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1 Comment

infocyde Over a year ago

I started down this path and in some scenarios it might work, but I ran into this pretty quickly stackoverflow.com/questions/41881169/…

Chamila Maddumage · Accepted Answer · 2020-03-06 07:55:34Z

1

I had the same issue with XUnit. The problem was with my database connection. Check your connection string is correct or not.

answered Mar 6, 2020 at 7:55

Chamila Maddumage

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RaZzLe · Accepted Answer · 2020-07-28 12:00:50Z

1

And, in my case, I mistakenly define my two different columns as identities on DbContext configurations like below,

builder.HasKey(e => e.HistoryId).HasName("HistoryId");
builder.Property(e => e.Id).UseSqlServerIdentityColumn(); //History Id should use identity column in this example

When I correct it like below,

builder.HasKey(e => e.HistoryId).HasName("HistoryId");
builder.Property(e => e.HistoryId).UseSqlServerIdentityColumn();

I have also got rid of this error.

answered Jul 28, 2020 at 12:00

RaZzLe

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Greg · Accepted Answer · 2025-06-19 21:56:55Z

Deployment of project failed: Value cannot be null. Parameter Name: Source

I got this error on a React & ASP.Net project when trying to run it, everything built but it complained when trying to "deploy". I was able to fix by noticing a .vscode folder was missing, and in it adding a launch.json file, from which I copied from a working solution. Clearly this wasn't part of what got stored in source control.

someProject.client\.vscode\launch.json

{
    "version": "0.2.0",
    "configurations": [
        {
            "type": "edge",
            "request": "launch",
            "name": "localhost (Edge)",
            "url": "https://localhost:63210",
            "webRoot": "${workspaceFolder}"
        },
        {
            "type": "chrome",
            "request": "launch",
            "name": "localhost (Chrome)",
            "url": "https://localhost:63210",
            "webRoot": "${workspaceFolder}"
        }
    ]
}

Franco · Accepted Answer · 2022-01-27 16:43:52Z

0

If this error comes up when you are trying to deploy the project, make sure your user account has enough permissions to do it.

answered Jan 27, 2022 at 16:43

Franco

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Jeff Widmer · Accepted Answer · 2023-12-19 19:42:20Z

0

I had marked some of my entities as internal (since the DbContect is internal) and then got this error "System.ArgumentNullException: Value cannot be null. Parameter name: source".

Make sure you mark your entities public and not internal:

internal class MyDbContext : DbContext
{
    internal MyDbContext(string connString) : base(connString) { }

    //Do not use internal; entities must be public for EF to see them.
    //NOT THIS: internal virtual DbSet<Customer> Customers { get; set; }
    public virtual DbSet<Customer> Customers { get; set; }
}

answered Dec 19, 2023 at 19:42

Jeff Widmer

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Jarin Farhad · Accepted Answer · 2019-04-01 21:41:15Z

-3

Take a Row in the database and make all the column null in that row like this "NULL".Now pass that NULL value using try catch or if else.

answered Apr 1, 2019 at 21:41

Jarin Farhad

11

1 Comment

Jason Loki Smith Over a year ago

this is a terrible idea

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