将JSON值添加到viewmodel中的ko.computed
我正忙着为我的web应用程序创建货币模块,我正在使用Yahoo Finance API返回我在本地数据库中定义的2种货币的货币兑换率。我从API获得了JSON数据,我只想使用ko.computed将我从Finance API收到的JSON数据绑定到我现有的Viewmodel。我不确定我是否应该使用ko.computed来实现这一点,所以任何建议都会大有帮助 这是我的密码:将JSON值添加到viewmodel中的ko.computed,json,knockout.js,Json,Knockout.js,我正忙着为我的web应用程序创建货币模块,我正在使用Yahoo Finance API返回我在本地数据库中定义的2种货币的货币兑换率。我从API获得了JSON数据,我只想使用ko.computed将我从Finance API收到的JSON数据绑定到我现有的Viewmodel。我不确定我是否应该使用ko.computed来实现这一点,所以任何建议都会大有帮助 这是我的密码: var currency = function (data) { var self = this;
var currency = function (data) {
var self = this;
self.CurrencyFrom = ko.observable(data.CurrencyFrom);
self.CurrencyTo = ko.observable(data.CurrencyTo);
self.ConversionRate = ko.computed(rates); // I WANT TO BIND THE VALUE FROM API HERE
}
var CurrencyModel = function (Currencies) {
var self = this;
self.Currencies = ko.observableArray(Currencies);
self.AddCurrency = function () {
self.Currencies.push({
CurrencyFrom: "",
CurrencyTo: "",
ConversionRate: ""
});
};
self.RemoveCurrency = function (Currency) {
self.Currencies.remove(Currency);
};
self.Save = function (Form) {
alert("Could Now Save: " + ko.utils.stringifyJson(self.Currencies));
};
$.ajax({
url: "CurrencyConfiguration.aspx/GetConfiguredCurrencies",
// Current Page, Method
data: '{}',
// parameter map as JSON
type: "POST",
// data has to be POSTed
contentType: "application/json; charset=utf-8",
// posting JSON content
dataType: "JSON",
// type of data is JSON (must be upper case!)
timeout: 10000,
// AJAX timeout
success: function (Result) {
var MappedCurrencies =
$.map(Result.d,
function (item) {
getRate(item.CurrencyFrom, item.CurrencyTo);
return new currency(item);
}
);
self.Currencies(MappedCurrencies);
},
error: function (xhr, status) {
alert(status + " - " + xhr.responseText);
}
});
};
//3rd Party JSON result from Yahoo Finance API
function getRate(from, to) {
var script = document.createElement('script');
script.setAttribute('src', "http://query.yahooapis.com/v1/public/yql?q=select%20rate%2Cname%20from%20csv%20where%20url%3D'http%3A%2F%2Fdownload.finance.yahoo.com%2Fd%2Fquotes%3Fs%3D" + from + to + "%253DX%26f%3Dl1n'%20and%20columns%3D'rate%2Cname'&format=json&callback=rates"); //HERE I CALL THE VALUE TO OBTAIN THE CONVERSION RATE FROM API
document.body.appendChild(script);
}
//I WANT TO ADD THIS TO MY VIEWMODEL
var rates = function parseExchangeRate(YahooData) {
var rate = YahooData.query.results.row.rate;
}
$(document).ready(function () {
var VM = new CurrencyModel();
ko.applyBindings(VM);
$('[rel=tooltip]').tooltip();
})
parseExchangeRate函数返回的JSON(Yahoo查询结果):
我看到您已经在使用jquery,所以我也将jquery用于JSONP。我使用了一个简单的ko.observable作为转换率,并添加了一个“裸”的ko.computed,它执行ajax请求并异步更新observable。如果您需要进一步的澄清,请告诉我 JSFIDLE示例(使用模拟数据而不是初始ajax): 更新代码:
var currency = function (data) {
var self = this;
self.CurrencyFrom = ko.observable(data.CurrencyFrom);
self.CurrencyTo = ko.observable(data.CurrencyTo);
self.ConversionRate = ko.observable(data.ConversionRate);
ko.computed(function () {
var from = self.CurrencyFrom(),
to = self.CurrencyTo();
if (!from || !to) {
self.ConversionRate("N/A");
return;
}
getRate(from, to).done(function (YahooData) {
console.log("got yahoo data for [" + from + "," + to + "]: ", YahooData);
self.ConversionRate(YahooData.query.results.row.rate);
});
});
}
var CurrencyModel = function (Currencies) {
var self = this;
self.Currencies = ko.observableArray(Currencies);
self.AddCurrency = function () {
self.Currencies.push(new currency({
CurrencyFrom: "",
CurrencyTo: "",
ConversionRate: ""
}));
};
self.RemoveCurrency = function (Currency) {
self.Currencies.remove(Currency);
};
self.Save = function (Form) {
alert("Could Now Save: " + ko.utils.stringifyJson(self.Currencies));
};
$.ajax({
url: "CurrencyConfiguration.aspx/GetConfiguredCurrencies",
// Current Page, Method
data: '{}',
// parameter map as JSON
type: "POST",
// data has to be POSTed
contentType: "application/json; charset=utf-8",
// posting JSON content
dataType: "JSON",
// type of data is JSON (must be upper case!)
timeout: 10000,
// AJAX timeout
success: function (Result) {
var MappedCurrencies = $.map(Result.d,
function (item) {
return new currency(item);
});
self.Currencies(MappedCurrencies);
},
error: function (xhr, status) {
alert(status + " - " + xhr.responseText);
}
});
};
//3rd Party JSON result from Yahoo Finance API
function getRate(from, to) {
return $.getJSON("http://query.yahooapis.com/v1/public/yql?q=select%20rate%2Cname%20from%20csv%20where%20url%3D'http%3A%2F%2Fdownload.finance.yahoo.com%2Fd%2Fquotes%3Fs%3D" + from + to + "%253DX%26f%3Dl1n'%20and%20columns%3D'rate%2Cname'&format=json&callback=?");
}
先生,您是一位绅士和学者!
var currency = function (data) {
var self = this;
self.CurrencyFrom = ko.observable(data.CurrencyFrom);
self.CurrencyTo = ko.observable(data.CurrencyTo);
self.ConversionRate = ko.observable(data.ConversionRate);
ko.computed(function () {
var from = self.CurrencyFrom(),
to = self.CurrencyTo();
if (!from || !to) {
self.ConversionRate("N/A");
return;
}
getRate(from, to).done(function (YahooData) {
console.log("got yahoo data for [" + from + "," + to + "]: ", YahooData);
self.ConversionRate(YahooData.query.results.row.rate);
});
});
}
var CurrencyModel = function (Currencies) {
var self = this;
self.Currencies = ko.observableArray(Currencies);
self.AddCurrency = function () {
self.Currencies.push(new currency({
CurrencyFrom: "",
CurrencyTo: "",
ConversionRate: ""
}));
};
self.RemoveCurrency = function (Currency) {
self.Currencies.remove(Currency);
};
self.Save = function (Form) {
alert("Could Now Save: " + ko.utils.stringifyJson(self.Currencies));
};
$.ajax({
url: "CurrencyConfiguration.aspx/GetConfiguredCurrencies",
// Current Page, Method
data: '{}',
// parameter map as JSON
type: "POST",
// data has to be POSTed
contentType: "application/json; charset=utf-8",
// posting JSON content
dataType: "JSON",
// type of data is JSON (must be upper case!)
timeout: 10000,
// AJAX timeout
success: function (Result) {
var MappedCurrencies = $.map(Result.d,
function (item) {
return new currency(item);
});
self.Currencies(MappedCurrencies);
},
error: function (xhr, status) {
alert(status + " - " + xhr.responseText);
}
});
};
//3rd Party JSON result from Yahoo Finance API
function getRate(from, to) {
return $.getJSON("http://query.yahooapis.com/v1/public/yql?q=select%20rate%2Cname%20from%20csv%20where%20url%3D'http%3A%2F%2Fdownload.finance.yahoo.com%2Fd%2Fquotes%3Fs%3D" + from + to + "%253DX%26f%3Dl1n'%20and%20columns%3D'rate%2Cname'&format=json&callback=?");
}