MySql.Query() can't return a string

"Anonymous function converted to a void returning delegate cannot return a value"

Code:

            mySql.Query(sql, connection, list =>
            {
                var sb = new StringBuilder();
                foreach (var entry in list)
                {
                    sb.AppendFormat("{0}", entry["steamid"]);
                }                string playerID = sb.ToString();
                return playerID;
            });

 

If your function is called "Name" change your function from: "void Name() {" to "string Name() {"

Void functions do not return values, where as that code returns a string, so your function needs to be of type string.