Question

如何将数据以json格式传给前端

Answer 1

将数据以json格式传给前端：
function generateDtb() {
//写入
var txtName = document.getElementById("txtName").value;
//创建数组
var dtb = new Array();
//通过循环把数据写入到数组并返回
for (var i = 0; i < firstGroup.length; i++) {

var row = new Object();
row.Name = txtName;
row.fullMoney = firstGroup[i].value;
row.discount = secondGroup[i].value;
dtb.push(row);
}
return dtb;
}

把数组转换成json串传入到后台：
$(function () {
//点击botton1
$("#lbtnOK").click(function () {
var url = "DiscountManger.aspx?ajax=1";
var dtb = generateDtb();
// var strName = document.getElementById("txtName").value;

if (dtb == null)
{ }
else {
//序列化对象
var postdata = JSON.stringify(dtb);
//异步请求
$.post(url, { json: postdata }, function (json) {
if (json) {
jBox.tip("添加成功！", "提示");
location.reload();
}
else {
jBox.tip("添加失败！", "提示");
location.reload();
}
}, "json")

}
});
});

在后台的操作：
首先判断是否需要传输数据

if (!IsPostBack)
{
//判断是否异步请求
if (Request.QueryString["ajax"] == "1")
{
ProcessRequest();
}

在这里进行对数据的处理：
/// <summary>
/// 处理异步请求
/// </summary>
private void ProcessRequest()
{
//存入要填写的策略
ArrayList arrDiscount = new ArrayList();
Response.ContentType = "text/html";
string json = Request.Form["json"];
//反序列化DataTable
if (json == null)
{
return;
}
else
{
DataTable newdtb = Json2Dtb(json);
for (int i = 0; i < newdtb.Rows.Count; i++)
{
Entity.StrategyDiscount enStrategyDiscount = new Entity.StrategyDiscount();
//打折方案名
enStrategyDiscount.name = newdtb.Rows[i]["Name"].ToString();
//商店ID
enStrategyDiscount.shopId = long.Parse(LoginInfo.ShopID);

enStrategyDiscount.fullMoney = Convert.ToDecimal(newdtb.Rows[i]["fullMoney"].ToString());
enStrategyDiscount.discount = Convert.ToDecimal(newdtb.Rows[i]["discount"].ToString());
//写入数据到数组
arrDiscount.Add(enStrategyDiscount);
}
//写入数据到数据库
IStrategyBLL strategy = new StrategyBLL();

if (strategy.AddStrategyDiscount(arrDiscount))
{
Response.Write("true");
Response.End();
}
else
{
Response.Write("false");
Response.End();
}

}

这里，我们需要把json转换成datatable
/// <summary>
/// Json转DataTable
/// </summary>
/// <param name="json"></param>
/// <returns></returns>
private DataTable Json2Dtb(string json)
{

JavaScriptSerializer jss = new JavaScriptSerializer();
ArrayList dic = jss.Deserialize<ArrayList>(json);
DataTable dtb = new DataTable();
if (dic.Count > 0)
{
foreach (Dictionary<string, object> drow in dic)
{
if (dtb.Columns.Count == 0)
{
foreach (string key in drow.Keys)
{
dtb.Columns.Add(key, drow[key].GetType());
}
}
DataRow row = dtb.NewRow();
foreach (string key in drow.Keys)
{
row[key] = drow[key];
}
dtb.Rows.Add(row);
}
}

return dtb;
}

这样，就可以把数据无刷新的写入到数据库。
当然，如果我们有一个从数据库读取的datatable，如果通过json显示在前台呢。
首先，我们需要把datatable转换为json数据

/// <summary>
/// DataTable转Json
/// </summary>
/// <param name="dtb"></param>
/// <returns></returns>
private string Dtb2Json(DataTable dtb)
{
JavaScriptSerializer jss = new JavaScriptSerializer();
ArrayList dic = new ArrayList();
foreach (DataRow row in dtb.Rows)
{
Dictionary<string, object> drow = new Dictionary<string, object>();
foreach (DataColumn col in dtb.Columns)
{
drow.Add(col.ColumnName, row[col.ColumnName]);
}
dic.Add(drow);
}
return jss.Serialize(dic);
}

然后写回到前台

/// <summary>
/// 处理异步请求
/// </summary>
private void ProcessRequest()
{
Response.ContentType = "text/html";
string json = Request.Form["json"];
//反序列化DataTable
DataTable newdtb = Json2Dtb(json);
//序列化DataTable为JSON
string back = Dtb2Json(newdtb);
Response.Write(back);
Response.End();
}

在前台接受显示：

$(function() {
//点击botton1
$("#botton1").click(function() {
createTable(json);
});
});

//显示Json中的数据
function createTable(json) {
var table = $("<table border='1'></table>");
for (var i = 0; i < json.length; i++) {
o1 = json[i];
var row = $("<tr></tr>");
for (key in o1) {
var td = $("<td></td>");
td.text(o1[key].toString());
td.appendTo(row);
}
row.appendTo(table);
}
table.appendTo($("#back"));
}