C# - Turning List of strings into a comma separated string

What you are looking for is most likely the static method Join from the string class. It is a very smooth way to create a comma separated string and you can easily separate it by any separator (delimiter) you wish. It can be used like below:

var someList = new List<string>
{
   "A","B","C"
};
var commaSeparatedString = string.Join(",", someList); 
//result will be "A,B,C"

If you want a space after each word you just add that to the first parameter of the Join:

var someList = new List<string>
{
   "A","B","C"
};

var commaSeparatedString = someList.ToCommaSeperatedString();
//result will be "A,B,C"

As previously mentioned you can use any separator, here is an example with a dash -:

var someList = new List<string>
{
   "A","B","C"
};
var commaSeparatedString = string.Join("-", someList); 
//result will be "A-B-C"

Using an extension method

If you need this in many places you can create a small extension method (ToCommaSeperatedString). Using the Join method is so simple to use that it might seem like overkill to create an extension method, but I will leave some examples here regardless. Below is an example on how to wrap the functionality of creating a comma separated string from a list of strings, in an extension method:

public static class StringExtentions
{
    public static string ToCommaSeperatedString(this IEnumerable<string> list)
    {
        return string.Join(",", list);
    }
}

And it can be used like below:

var someList = new List<string>
{
   "A","B","C"
};

var commaSeparatedString = someList.ToCommaSeperatedString();
//result will be "A,B,C"

Alternatively you can provide the separator and make a ToSeperatedString method:

public static class StringExtentions
{
    public static string ToSeperatedString(this IEnumerable<string> list 
       , string separator)
    {
        return string.Join(separator, list);
    }
}

And it can be used like below:

var someList = new List<string>
{
   "A","B","C"
};

var commaSeparatedString = someList.ToSeperatedString(",");
//result will be "A,B,C"

That is all

That is an easy way to turn a list of strings into a comma separated string. Please leave a comment down below with your thoughts!