[c#] How to resolve Value cannot be null. Parameter name: source in linq?

I don't know why I get this kind of error. It happens sometimes, and I suspicious of my code that still have thread running while I close my Application. So when I open again it happens.

Value cannot be null.
Parameter name: source
StackTree :
   at System.Linq.Enumerable.Where[TSource](IEnumerable`1 source, Func`2 predicate)
   at Susenas2015.ViewModels.Kuesioner.VMVsen15_KVal.SettingValidationAndRange(List`1 listTextBox, List`1 listCheckBox, TabControl tabControl) in d:\handita\Office\Project\Susenas 2015\Aplikasi Template Survei\Susenas2015\ViewModels\Kuesioner\VMVsen15_KVal.cs:line 430
   at Susenas2015.ViewModels.Kuesioner.VMVsen15_KVal.vSen15_K_Loaded(Object sender, RoutedEventArgs e) in d:\handita\Office\Project\Susenas 2015\Aplikasi Template Survei\Susenas2015\ViewModels\Kuesioner\VMVsen15_KVal.cs:line 846
   at System.Windows.RoutedEventHandlerInfo.InvokeHandler(Object target, RoutedEventArgs routedEventArgs)
   at System.Windows.EventRoute.InvokeHandlersImpl(Object source, RoutedEventArgs args, Boolean reRaised)
   at System.Windows.UIElement.RaiseEventImpl(DependencyObject sender, RoutedEventArgs args)
   at System.Windows.UIElement.RaiseEvent(RoutedEventArgs e)
   at System.Windows.BroadcastEventHelper.BroadcastEvent(DependencyObject root, RoutedEvent routedEvent)
   at System.Windows.BroadcastEventHelper.BroadcastLoadedEvent(Object root)
   at MS.Internal.LoadedOrUnloadedOperation.DoWork()
   at System.Windows.Media.MediaContext.FireLoadedPendingCallbacks()
   at System.Windows.Media.MediaContext.FireInvokeOnRenderCallbacks()
   at System.Windows.Media.MediaContext.RenderMessageHandlerCore(Object resizedCompositionTarget)
   at System.Windows.Media.MediaContext.RenderMessageHandler(Object resizedCompositionTarget)
   at System.Windows.Media.MediaContext.Resize(ICompositionTarget resizedCompositionTarget)
   at System.Windows.Interop.HwndTarget.OnResize()
   at System.Windows.Interop.HwndTarget.HandleMessage(WindowMessage msg, IntPtr wpa`

My code here it is

    private void SettingValidationAndRange(List<TextBox> listTextBox, List<CheckBox> listCheckBox, TabControl tabControl)
        {

            List<string> listNotDeclare = new List<string>();

            foreach (var textB in listTextBox)
            {
                if (textB.Tag != null)
                    break;

                Metadata metadata = ListMetadataKor.Where(
                    x => "text" + x.Field == textB.Name // this line 430

                ).FirstOrDefault();

                if (metadata == null)
                {
                    if (!string.IsNullOrEmpty(textB.Name))
                        listNotDeclare.Add(textB.Name);
                }
                else
                {
                    metadata.TabControl = tabControl;
                    textB.Tag = metadata;
                }

                textB.AddEvents();
                textB.AutomateFocus();

            }

            if (listNotDeclare.Count > 0)
            {
                Clipboard.SetText(string.Join(",", listNotDeclare.ToArray()));
                Dialog.Info("Ada beberapa Metadata tidak ditemukan data sudah dicopy ke clipboard");
            }

        }

When I start my application for my first time, it doesn't get any error. It happens when I open in 2nd or more. And if I open my application it would stuck in that code.

How I can solve this? I'm pretty sure that my Property ListMetadataKor is not null

And ListMetadataKor is instance of List<Metadata> object that I have created. It happens only in rare cases. And I don't know to solve it

UPDATE

This is my code in image

I fill ListMetadataKor with this code

BWHelper.Run((s, e) =>
{
    DataTable dataMetaDataKOR = ExcelHelper.GetDataTableFromExcel(
        AppConstants.FILE_METADATA, AppConstants.SHEET_METADATA_KOR
    );

    DataTable dataKonsistensiKOR = ExcelHelper.GetDataTableFromExcel(
         AppConstants.FILE_METADATA, AppConstants.SHEET_KONSISTENSI_KOR
     );

    listKonsistensiKor = Tools.ToolConvert.GetKonsistensi(dataKonsistensiKOR);
    listMetadataKor = Tools.ToolConvert.GetMetadata(dataMetaDataKOR);

    foreach (Metadata metadata in listMetadataKor)
    {
        metadata.Range.ProsesRange();
    }

}, (s, e) =>
{
    try
    {
        kor = new VSEN15_K() { Title = "Validasi Susenas - KOR" };
        kor.DataContext = new VMVsen15_KVal(rtSusenas.MasterRT, kor, this, listKonsistensiKor, listMetadataKor);
        kor.PreviewKeyDown += EventsCollection.EnterAsTabPreviewKeyDown;
        vmHome.HideLoading();
        UpdateMetaDataEntriKOR(RTSusenas.MasterRT);
        kor.ShowDialog();
    }
    catch (Exception Ex)
    {
        vmHome.HideLoading();
        Dialog.Error(Ex);
    }
});

And then I throw the variable through constructor of my class

 public VMVsen15_KVal(
        MasterRT masterRT,
        VSEN15_K vSen15_K,
        IDaftarSusenas vmDaftarRTSusenas,
        List<Konsistensi> listKonsistensiKor,
        List<Metadata> listMetadataKor

        )
    {

        ListArtDetail = new ObservableCollection<ARTDetailVal>();

        this.ListKonsistensiKor = listKonsistensiKor;
        this.ListMetadataKor = listMetadataKor;

My tools konsistensi like this

public static List<Konsistensi> GetKonsistensi(DataTable dataTable)
{
    List<Konsistensi> listMetadata = new List<Konsistensi>();
    for (int i = 0; i < dataTable.Rows.Count; i++)
    {
        Konsistensi k = new Konsistensi();
        object[] required = new object[] { DBNull.Value, "" };
        k.Field = dataTable.Rows[i][FIELD].ToString();
        if (string.IsNullOrWhiteSpace(k.Field)) continue;
        k.Message = dataTable.Rows[i][MESSAGE].ToString();
        var obj = dataTable.Rows[i][ORDER];
        k.Order = !required.Contains(dataTable.Rows[i][ORDER]) ? Convert.ToInt32(dataTable.Rows[i][ORDER]) : (int?)null;
        k.Page = !required.Contains(dataTable.Rows[i][PAGE]) ? Convert.ToInt32(dataTable.Rows[i][PAGE]) : (int?)null;
        k.Perlakuan = dataTable.Rows[i][PERLAKUAN].ToString();
        k.RelFields = dataTable.Rows[i][RELFIELDS].ToString();
        k.Rule = dataTable.Rows[i][RULE].ToString();

        if (dataTable.Rows[i][LEVEL].ToString().ToUpper() == ("ART"))
            k.LevelKonsistensi = LevelKonsistensi.ART;
        else if (dataTable.Rows[i][LEVEL].ToString().ToUpper() == ("RT"))
            k.LevelKonsistensi = LevelKonsistensi.RT;
        else if (dataTable.Rows[i][LEVEL].ToString().ToUpper() == ("RTWARNING"))
            k.LevelKonsistensi = LevelKonsistensi.RTWarning;
        else if (dataTable.Rows[i][LEVEL].ToString().ToUpper().Contains("ARTWARNING"))
            k.LevelKonsistensi = LevelKonsistensi.ARTWarning;
        else
            k.LevelKonsistensi = LevelKonsistensi.Lain;

        //k.LevelKonsistensi = dataTable.Rows[i][LEVEL].ToString().Contains("ART") ? LevelKonsistensi.ART : LevelKonsistensi.RT;
        if (k.IsEmpty())
            continue;

        listMetadata.Add(k);
    }
    return listMetadata;
}

When you call a Linq statement like this:

// x = new List<string>();
var count = x.Count(s => s.StartsWith("x"));

You are actually using an extension method in the System.Linq namespace, so what the compiler translates this into is:

var count = Enumerable.Count(x, s => s.StartsWith("x"));

So the error you are getting above is because the first parameter, source (which would be x in the sample above) is null.

System.ArgumentNullException: Value cannot be null. Parameter name: value

This error message is not very helpful!

You can get this error in many different ways. The error may not always be with the parameter name: value. It could be whatever parameter name is being passed into a function.

As a generic way to solve this, look at the stack trace or call stack:

Test method GetApiModel threw exception: 
System.ArgumentNullException: Value cannot be null.
Parameter name: value
    at Newtonsoft.Json.JsonConvert.DeserializeObject(String value, Type type, JsonSerializerSettings settings)

You can see that the parameter name value is the first parameter for DeserializeObject. This lead me to check my AutoMapper mapping where we are deserializing a JSON string. That string is null in my database.

You can change the code to check for null.

Value cannot be null. Parameter name: source

Above error comes in situation when you are querying the collection which is null.

For demonstration below code will result in such an exception.

Console.WriteLine("Hello World");
IEnumerable<int> list = null;
list.Where(d => d ==4).FirstOrDefault();

Here is the output of the above code.

Hello World Run-time exception (line 11): Value cannot be null. Parameter name: source

Stack Trace:

[System.ArgumentNullException: Value cannot be null. Parameter name: source] at Program.Main(): line 11

In your case ListMetadataKor is null. Here is the fiddle if you want to play around.