Amazing that I still find BCL classes every day in .NET to do simple tasks. I had a feeling that something may exist but didn’t expect to find it in the System.Configuration namespace.
using System.Configuration;
CommaDelimitedStringCollection strings = new CommaDelimitedStringCollection();
foreach(string item in myOtherCollection)
{
strings.Add(item);
}
//Spit out your comma separated string
string output = strings.ToString();
Simple!