ajax json 数据

json_ajax_Datable_IList(T).rar

使用datatable作为后台数据源

例子： 关于JSON的学习/学习json1_datatable.aspx; ToJson.ashx;

<script type="text/javascript">
    window.onload=function(){
        xmlhttprequest.open("POST","../ToJson.ashx",true);
        xmlhttprequest.onreadystatechange=setSelect;
        xmlhttprequest.send(null);
    }
    function setSelect(){
        if(xmlhttprequest.readyState==4){
            if(xmlhttprequest.status==200){
                var son=xmlhttprequest.responseText;
                alert(son);
                var json=eval("("+son+")");
                alert(json.Suppliers[0].CompanyName);
            }
        }
    }
</script>

{"Suppliers":[{"SupplierID":"1","CompanyName":"Exotic Liquids","Address":"49 Gilbert St.","City":"London","Country":"UK","Phone":"(171) 555-2222"},{"SupplierID":"2","CompanyName":"New Orleans Cajun Delights","Address":"P.O. Box 78934","City":"New Orleans","Country":"USA","Phone":"(100) 555-4822"},{"SupplierID":"3","CompanyName":"Grandma Kelly's Homestead","Address":"707 Oxford Rd.","City":"Ann Arbor","Country":"USA","Phone":"(313) 555-5735"},{"SupplierID":"4","CompanyName":"Tokyo Traders","Address":"9-8 Sekimai Musashino-shi","City":"Tokyo","Country":"Japan","Phone":"(03) 3555-5011"},{"SupplierID":"5","CompanyName":"Cooperativa de Quesos 'Las Cabras'","Address":"Calle del Rosal 4","City":"Oviedo","Country":"Spain","Phone":"(98) 598 76 54"},
……………………………………

然后用EVAL（）把后台传过来的responseText对象转化为js对象

然后用json.Suppliers[index].SupplierID
json.Suppliers[index].CompanyName等访问
比使用Msxml2.DOMDocument控件解析XML方便

public void ProcessRequest (HttpContext context) {
        context.Response.ContentType = "text/plain";
        SuppliersBLL bll = new SuppliersBLL();
        Northwind.SuppliersDataTable table = bll.GetSuppliers();
        context.Response.Write(DataTableToJson(table));
        context.Response.End();
        
    }

    private static string DataTableToJson(Northwind.SuppliersDataTable dt)
    {
        System.Text.StringBuilder jsonBuilder = new System.Text.StringBuilder();
        jsonBuilder.Append("{\"");
        jsonBuilder.Append(dt.TableName.ToString());
        jsonBuilder.Append("\":[");
        for (int i = 0; i < dt.Rows.Count; i++)
        {
            jsonBuilder.Append("{");
            for (int j = 0; j < dt.Columns.Count; j++)
            {
                jsonBuilder.Append("\"");
                jsonBuilder.Append(dt.Columns[j].ColumnName);
                jsonBuilder.Append("\":\"");
                jsonBuilder.Append(dt.Rows[i][j].ToString());
                jsonBuilder.Append("\",");
            }
            jsonBuilder.Remove(jsonBuilder.Length - 1, 1);
            jsonBuilder.Append("},");
        }
        jsonBuilder.Remove(jsonBuilder.Length - 1, 1);
        jsonBuilder.Append("]");
        jsonBuilder.Append("}");
        return jsonBuilder.ToString();
    }

使用泛型数组作为后台数据源

关于JSON的学习/使用json_net序列化实体层/Default.aspx; Handler2.ashx;

<script type="text/javascript">
    window.onload=function(){
        xmlhttprequest.open("POST","http://www.cnblogs.com/Handler2.ashx",true);
        xmlhttprequest.onreadystatechange=setSelect;
        xmlhttprequest.send(null);
    }
    function setSelect(){
        if(xmlhttprequest.readyState==4){
            if(xmlhttprequest.status==200){
                var son=xmlhttprequest.responseText;
                alert(son);
                var json=eval("("+son+")");
                alert(json[0].ID);
                alert(json[0].CompanyName);
            }
        }
    }
</script>

{"ID":1,"CompanyName":"Exotic Liquids"},{"ID":2,"CompanyName":"New Orleans Cajun Delights"},{"ID":3,"CompanyName":"Grandma Kelly's Homestead"},{"ID":4,"CompanyName":"Tokyo Traders"},{"ID":5,"CompanyName":"Cooperativa de Quesos 'Las Cabras'"},{"ID":6,"CompanyName":"Mayumi's"},{"ID":7,"CompanyName":"Pavlova, Ltd."},{"ID":8,"CompanyName":"Specialty Biscuits, Ltd."},{"ID":9,"CompanyName":"PB Knäckebröd AB"},{"ID":10,"CompanyName":"Refrescos Americanas LTDA"},{"ID":11,"CompanyName":"Heli Süßwaren GmbH & Co. KG"},

eval转化为js对象，var json=eval("("+son+")")
json[0].ID  //output: 1

 Json.NET。它方便我们读取从浏览器流向服务器的JSON对象，也方便在响应流中写入JSON对象。这里下载：Json.NET。

加入Newtonsoft.Json DLL
新建一个有supplierID，CompanyName两个字段的model类supplier

    public void ProcessRequest(HttpContext context)
    {
        context.Response.ContentType = "text/plain";
        SuppliersBLL bll = new SuppliersBLL();
        Northwind.SuppliersDataTable table = bll.GetSuppliers();
        IList<Supplier> lst = reSupplierList(table);
        context.Response.Write(JavaScriptConvert.SerializeObject(lst));
        context.Response.End();
    }
    public IList<Supplier> reSupplierList(Northwind.SuppliersDataTable table)
    {
        IList<Supplier> lst = new List<Supplier>();
        foreach (Northwind.SuppliersRow item in table)
        {
            Supplier model = new Supplier();
            model.ID = item.SupplierID;
            model.CompanyName = item.CompanyName;
            lst.Add(model);
        }
        return lst;
    }