How define charset of csv file

<pre lang="xml">/// </summary>
   public class CsvRow : List<string>
   {
       public string LineText { get; set; }
   }

   /// <summary>
   /// Class to write data to a CSV file
   /// </summary>
   public class CsvFileWriter : StreamWriter
   {
       public CsvFileWriter(Stream stream)
           : base(stream)
       {
       }

       public CsvFileWriter(string filename)
           : base(filename)
       {
       }

       /// <summary>
       /// Writes a single row to a CSV file.
       /// </summary>
       /// <param name="row">The row to be written</param>
       public void WriteRow(CsvRow row)
       {
           StringBuilder builder = new StringBuilder();
           bool firstColumn = true;
           foreach (string value in row)
           {
               // Add separator if this isn't the first value
               if (!firstColumn)
                   builder.Append(';');
               // Implement special handling for values that contain comma or quote
               // Enclose in quotes and double up any double quotes
               if (value.IndexOfAny(new char[] {'"', ','}) != -1)
                   builder.AppendFormat("\"{0}\"", value.Replace("\"", "\"\""));
               else
                   builder.Append(value);
               firstColumn = false;
           }
           row.LineText = builder.ToString();
           WriteLine(row.LineText,Encoding.UTF8);
       }
   }

using (CsvFileWriter writer = new CsvFileWriter("WriteTest.csv"))
           {


                   for (int j = 0; j < toExcelData.Count; j++)
                   {
                       CsvRow row = new CsvRow();
                       string[] bufzz = toExcelData[j].Split(';');
                       for (int i = 0; i<bufzz.Length; i++)
                       {
                           //for (int h=0; h<)
                           row.Add(bufzz[i]);
                       }
                       writer.WriteRow(row);
                   }


           }