jquery+json实现数据二级联动的方法_jquery

if (context.Request.QueryString["ProID"] != null && context.Request.QueryString["proType"] != null) 
{ 
 string pcode = Convert.ToString(context.Request.QueryString.GetValues("ProID")[0]); 
 string strSQL = "select cityname,ccode from CD_CityInfo where pcode='" + pcode + "' "; 
 //执行T-SQL语句 返回DataTable 
 DataTable dt = Snell.SnCode.DataBase.SQLServerHelper.Query(strSQL).Tables[0]; 
 StringBuilder sb = new StringBuilder(); 
 sb.Append(CreateJsonParameters(dt)); 
 //根据省份编号获取信息 获取信息 
 if (sb.Length > 0) 
 { 
 context.Response.ClearContent(); 
 context.Response.ContentEncoding = System.Text.Encoding.UTF8; 
 context.Response.Write(sb.ToString()); 
 context.Response.End(); 
 } 
}
#region 根据Datatable的数据结构转换成json数据 
public string CreateJsonParameters(DataTable dt) 
{ 
 System.Text.StringBuilder sb = new System.Text.StringBuilder(); 
 if (dt != null && dt.Rows.Count > 0) 
 { 
 sb.Append("["); 
 for (int i = 0; i < dt.Rows.Count; i++) 
 { 
 sb.Append("{"); 
 for (int j = 0; j < dt.Columns.Count; j++) 
 { 
 //如果值不是最后一个则添加逗号分隔
 if (j < dt.Columns.Count - 1) 
 { 
 sb.Append("\"" + dt.Columns[j].ColumnName.ToString() + "\":" + "\"" + dt.Rows[i][j].ToString() + "\","); 
 } 
 //如果值为最后个字符则不添加逗号
 else if (j == dt.Columns.Count - 1) 
 { 
 sb.Append("\"" + dt.Columns[j].ColumnName.ToString() + "\":" + "\"" + dt.Rows[i][j].ToString() + "\""); 
 } 
 } 
 //如果为最后一个值的话 则不添加逗号
 if (i == dt.Rows.Count - 1) 
 { 
 sb.Append("}"); 
 } 
 else 
 { 
 sb.Append("},"); 
 } 
 } 
 sb.Append("]"); 
 return sb.ToString(); 
 } 
 else { return null; } 
} 
#endregion