DataTable转为JSON数据格式代码

public static string GetJSON(DataTable dt) 
{ 
    StringBuilder sb = new StringBuilder(); 
    sb.Append("{\"totalCount\":" + dt.Rows.Count + ",\"data\":"); 
    sb.Append("["); 
    try 
    { 
        if (dt.Rows.Count > 0) 
        {
            Hashtable ht = new Hashtable();
            for (int i = 0; i < dt.Columns.Count; i++)
            {
                ht.Add(i, dt.Columns[i].ColumnName);
            }
            for (int i = 0; i < dt.Rows.Count; i++)
            {
                sb.Append("{");
                for (int j = 0; j < dt.Columns.Count; j++)
                {
                    sb.Append(string.Format("\"{0}\":\"{1}\",",
                    ht[j], dt.Rows[i][j].ToString()));
                }
                sb.Remove(sb.ToString().LastIndexOf(","), 1);
                sb.Append("},");
            }
            sb.Remove(sb.ToString().LastIndexOf(","), 1);2
            ht.Clear();
            ht = null;
        }
    }  
    catch (Exception ex)
    {
        throw new Exception(ex.Message);
    }
    finally
    {
         sb.Append("]}");
    }
    return sb.ToString();
}