C# – Convert a List to a string

There are two good ways to convert a List<T> to a string:

• Use String.Join() and specify a delimiter (such as a comma, newline, tab, etc…).
• Loop through the items and add them to a StringBuilder.

I’ll show examples of both approaches.

Using String.Join()

String.Join() is the simplest way to convert a List to a string. With this method, you pass in the List and a delimiter and it outputs a string. You can use any delimiter you want. Here’s an example of converting a List to a comma-separated string (by passing in “,” as the delimiter):

var list = new List<string>()
{
    "Bob", "Linda", "Tina", "Gene", "Louise"
};

string names = String.Join(",", list);

Console.WriteLine(names);
Code language: C# (cs)

This outputs the following comma-separated string (notice there’s no trailing comma):

Bob,Linda,Tina,Gene,LouiseCode language: plaintext (plaintext)

String.Join() can convert lists of any type. Internally, it calls ToString() to convert each item to a string. Here’s an example of converting a List of integers to a newline-separated string:

var list = new List<int>()
{
    1,2,3,4,5
};

string names = String.Join(Environment.NewLine, list);

Console.WriteLine(names);
Code language: C# (cs)

Read more about the reverse option: converting a string to a list of integers.

This outputs the newline-separated string of integers:

1
2
3
4
5Code language: plaintext (plaintext)

Using StringBuilder and a foreach loop

You can convert a List to a string with a foreach loop and StringBuilder.

• For each item, add the item and a delimiter with StringBuilder.Append().
• Trim off the trailing delimiter at the end with StringBuilder.Remove().
• Get the string with StringBuilder.ToString().

The following example shows how to do this. This converts a List of objects to a comma-separated string with a loop and StringBuilder:

using System.Text;

var list = new List<Person>()
{
    new Person { Name = "Bob" },
    new Person { Name = "Linda" },
    new Person { Name = "Teddy" }
};

var sb = new StringBuilder();
var delimiter = ",";

foreach(var person in list)
{
    sb.Append(person.Name);
    sb.Append(delimiter);
}

//Remove the trailing delimiter
if (sb.Length > 0)
    sb.Remove(sb.Length - 1, 1);

var names = sb.ToString();

Console.WriteLine(names);
Code language: C# (cs)

This creates a CSV string. Read more about parsing CSV strings.

This outputs the following comma-separated string of names:

Bob,Linda,TeddyCode language: plaintext (plaintext)

Notice that there’s no trailing comma. It was removed after the loop with StringBuilder.Remove(). This is more efficient than conditionally adding the delimiter within the loop.