你可以使用 AsyncFunction 和 AsyncEvaluateContext 来对异步方法对函数进行求值。
你可以使用 AsyncFunctionEvaluateMode 类来指定函数是如何求值的。
示例代码
以下代码使用 AsyncFunction 类定义了一个异步函数。在异步函数中添加了一个 setTimeOut 来模拟服务器端求值。
JavaScript
var asum = function () {}
//Define a class "ASUM" that extends AsyncFunction
asum.prototype = new GC.Spread.CalcEngine.Functions.AsyncFunction("ASUM", 1, 255);
//Set default value to "Loading..."
asum.prototype.defaultValue = function () { return "Loading..."; };
//Override the evaluateAsync function
asum.prototype.evaluateAsync = function (context) {
var args = arguments;
//Use a timeout to simulate the server side evaluate or use an ajax post
setTimeout(function () {
//Evaluation logic
var result = 0;
for (var i = 0; i < args.length; i++) {
result += args[i];
}
result *= 2;
//Set the async evaluate result to CalcEngine
context.setAsyncResult(result);
}, 2000);
}
//Or use Ajax post
//$.ajax({
//url: '@Url.Action("ASUM", "Home")',
//type: "POST",
//data: JSON.stringify(args),
//contentType: "application/json,charset=UTF-8",
//success: function (data) {
//context.SetAsyncResult(data.result);
//}
//});
//Add the ASUM function to spread and set the formula
activeSheet.addCustomFunction(new asum());
activeSheet.setValue(0, 0, 5);
activeSheet.setValue(0, 1, 15);
activeSheet.setFormula(1, 1, "ASUM(A1,B1)");
以下代码使用了 Refresh formula 来对公式进行重新求值。
HTML
<!DOCTYPE html>
<html>
<head>
<title>Spread.Sheets</title>
<link href="./css/gc.spread.sheets.10.x.x.css" rel="stylesheet" type="text/css" />
<script type="text/javascript" src="./scripts/gc.spread.sheets.all.10.x.x.min.js"></script>
<!--jQuery References-->
<script src="http://code.jquery.com/jquery-2.0.2.js" type="text/javascript"></script>
<script type="text/javascript">
window.onload = function(){
var spread = new GC.Spread.Sheets.Workbook(document.getElementById("ss"),{sheetCount:3});
var sheet = spread.getActiveSheet();
var GetNumberFromServer = function () {
}
GetNumberFromServer.prototype = new GC.Spread.CalcEngine.Functions.AsyncFunction("GETNUMBERFROMSERVER", 2, 2);
GetNumberFromServer.prototype.evaluate = function (context, arg1, arg2) {
var self = this;
$.get('http://xa-tools-shdev/asyncfunction/api/values/' + (arg1 || 1), function (value) {
context.setAsyncResult(value);
});
}
GC.Spread.CalcEngine.Functions.defineGlobalCustomFunction("GETNUMBERFROMSERVER", new GetNumberFromServer());
sheet.setValue(0, 0, 'ChangeValue');
sheet.setValue(0, 1, 'Formula');
sheet.setValue(0, 2, 'Result');
sheet.setValue(0, 3, 'Comments');
sheet.setValue(1, 3, 'On A2 changed');
sheet.setValue(2, 3, 'On A2 changed');
sheet.setValue(3, 3, 'Evaluate once');
sheet.setValue(4, 3, 'Every 2 seconds');
sheet.setValue(1, 0, 1);
sheet.setValue(1, 1, '=GetNumberFromServer(A2)');
sheet.setValue(2, 1, '=Refresh(GetNumberFromServer(A2), 0)');
sheet.setValue(3, 1, '=Refresh(GetNumberFromServer(A2), 1)');
sheet.setValue(4, 1, '=Refresh(GetNumberFromServer(A2), 2, 2000)');
sheet.setFormula(1, 2, '=GetNumberFromServer(A2)');
sheet.setFormula(2, 2, '=Refresh(GetNumberFromServer(A2), 0)');
sheet.setFormula(3, 2, '=Refresh(GetNumberFromServer(A2), 1)');
sheet.setFormula(4, 2, '=Refresh(GetNumberFromServer(A2), 2, 2000)');
sheet.setColumnWidth(0, 100);
sheet.setColumnWidth(1, 300);
sheet.setColumnWidth(2, 200);
sheet.setColumnWidth(3, 200);
sheet.setValue(7, 1, "=Refresh(now(), 2, 1000)");
sheet.setValue(7, 3, "Every 1 seconds");
sheet.setFormula(7, 2, "=Refresh(now(), 2, 1000)");
var GetTimeFromServer = function () {
}
GetTimeFromServer.prototype = new GC.Spread.CalcEngine.Functions.AsyncFunction("GETTIMEFROMSERVER", 2, 2);
GetTimeFromServer.prototype.evaluate = function (context) {
$.get('http://xa-tools-shdev/asyncfunction/api/time/', function (value) {
context.setAsyncResult(value);
});
}
GetTimeFromServer.prototype.evaluateMode = function () {
return 2;
};
GetTimeFromServer.prototype.interval = function () {
return 1000;
};
GC.Spread.CalcEngine.Functions.defineGlobalCustomFunction("GETTIMEFROMSERVER", new GetTimeFromServer());
sheet.setValue(10, 1, "=GetTimeFromServer()");
sheet.setValue(10, 3, "Every 1 seconds");
sheet.setFormula(10, 2, "=GetTimeFromServer()");
sheet.getCell(10, 2).hAlign(GC.Spread.Sheets.HorizontalAlign.right);
}
</script>
</head>
<body>
<div id="ss" style="width:100%;height:500px;border:1px solid gray"></div>
</body>
</html>