Why is the delimiter excluded in this String.Join? C#

Question

I have an ObservableCollection<T> that I use for binding that I want to put into a String.Join statement, but I don't understand why it is giving the results I am getting and how to fix it?

This is the code I am using to get the result,

First I am getting the data I need via this LINQ query,

public static IEnumerable<string> GetNursingHomeNames(string home)
{
    return DataContext.NursingHomeNameServerTables.Where(p => p.Nursing_Home_Section == home)
                        .Select(p => p.Nursing_Home_Name).Distinct();
}

I then put it into the ObservableCollection<T> (You may be wondering why I am not using an ObservableCollection<T> with the LINQ query, but I have my reasons.)

public static void NursingHomeNamesCollection(ObservableCollection<string> nursingHomeNames, string nursingHomeSection)
{
    var homeNames = GetNursingHomeNames(nursingHomeSection);
    if (homeNames == null)
    {
        return;
    }
    foreach (var item in homeNames)
    {
        nursingHomeNames.Add(item);
    }
}

This is the property in the main window,

 public ObservableCollection<string> NursingHomeNames { get; set; } =
                   new ObservableCollection<string>(); 

Then

Than I use Join to get the results for a specific purpose I need,

var result = String.Join(@",", NursingHomeNames.ToList());

And this gives the following result where there is no delimiter only a space,

foo bar bat baz

However, if just do this,

ObservableCollection<string> observableCol = new ObservableCollection<string>() { "foo", "bar", "bat", "baz" };

var result = String.Join(@",", observableCol.ToList());

The result is displayed with the delimiters in place.

foo,bar,bat,baz

Why is it doing this and is there a way to ensure the delimiters are correctly placed?

I know I have to work on my naming conventions.

EDIT: In the debuger, this is what I see,

When assigning the collection to a variable named data and viewing the results in the Watch Window

var data = NursingHomeNames.ToList();

Count = 4

[0] "foo"

[1] "bar"

[2] "bat"

[3] "baz"

However, I cannot reproduce this using any other code that does not use the LINQ query that pulls the data from the database. I tried making a new list and passing that list through the same code, but the error does not occur. I am sorry, but I can't post an example that can be reproduced.

Answer 1

As it turns out, after weeks of effort to figure this out, the answer to be had was with the comment that @Panagiotis Kanavos and @CodeCaster made.

I was using a Unicode character that looked like a comma and it was therefore creating a different behavior than what I was expecting.

Answer 2

In method

public static void NursingHomeNamesCollection(string nursingHomeSection)

you get string parameter to input. After in this method scope you add this string into static collection, but item in this scope is a char .

foreach (var item in homeNames)

You're trying to add a character at a time and join one big string. You need get collection to input of this method.