//DataTable 转换成json，这里带了“total”，传给客户端的数据总数，不传这个，客户端不会显示总数据是多少条多少条的。
public static string CreateJsonParameters(DataTable dt, bool displayCount, int totalcount)
    {
      StringBuilder JsonString = new StringBuilder();
      //Exception Handling    
      if (dt != null)
      {
        JsonString.Append("{ ");
        if (displayCount)
        {
          JsonString.Append("\"total\":");
          JsonString.Append(totalcount);
          JsonString.Append(",");
        }
        JsonString.Append("\"rows\":[ ");
        for (int i = 0; i < dt.Rows.Count; i++)
        {
          JsonString.Append("{ ");
          for (int j = 0; j < dt.Columns.Count; j++)
          {
            if (j < dt.Columns.Count - 1)
            {
              //if (dt.Rows[i][j] == DBNull.Value) continue;
              if (dt.Columns[j].DataType == typeof(bool))
              {
                JsonString.Append("\"" + dt.Columns[j].ColumnName + "\":" +
                         dt.Rows[i][j].ToString().ToLower() + ",");
              }
              else if (dt.Columns[j].DataType == typeof(string))
              {
                JsonString.Append("\"" + dt.Columns[j].ColumnName + "\":" + "\"" +
                         dt.Rows[i][j].ToString().Replace("\"", "\\\"") + "\",");
              }
              else
              {
                JsonString.Append("\"" + dt.Columns[j].ColumnName + "\":" + "\"" + dt.Rows[i][j] + "\",");
              }
            }
            else if (j == dt.Columns.Count - 1)
            {
              //if (dt.Rows[i][j] == DBNull.Value) continue;
              if (dt.Columns[j].DataType == typeof(bool))
              {
                JsonString.Append("\"" + dt.Columns[j].ColumnName + "\":" +
                         dt.Rows[i][j].ToString());
              }
              else if (dt.Columns[j].DataType == typeof(string))
              {
                JsonString.Append("\"" + dt.Columns[j].ColumnName + "\":" + "\"" +
                         dt.Rows[i][j].ToString().Replace("\"", "\\\"") + "\"");
              }
              else
              {
                JsonString.Append("\"" + dt.Columns[j].ColumnName+ "\":" + "\"" + dt.Rows[i][j] + "\"");
              }
            }
          }
          /*end Of String*/
          if (i == dt.Rows.Count - 1)
          {
            JsonString.Append("} ");
          }
          else
          {
            JsonString.Append("}, ");
          }
        }
        JsonString.Append("]");
        JsonString.Append("}");
        return JsonString.ToString().Replace("\n", "");
      }
      else
      {
        return null;
      }
    }