首先抱歉糟糕的标题,只是想不出更好。
我是JavaScript的新手,这可能是我没有得到这个的唯一原因 - 请不要爆炸我。
我想要做的只是使用JavaScript客户端对象模型从Sharepoint站点查询多个 Sharepoint列表(甚至可能多次)。我能够在网上找到许多工作示例,如何从列表中检索数据并使用它。但我对异步和回调概念如此陌生,以至于我无法将概念转移到我的需要。 我实际上必须复制所有变量和函数x次吗?
以下是我拨打一个电话的原因:
var listAItems;
$(document).ready(function() {
ExecuteOrDelayUntilScriptLoaded(LoadChartData, "sp.js");
});
function LoadChartData() {
context = SP.ClientContext.get_current();
var listA = context.get_web().get_lists().getByTitle("ListA");
var camlQuery = SP.CamlQuery.createAllItemsQuery();
this.listAItems = listA.getItems(camlQuery);
context.load(listAItems);
context.executeQueryAsync(ReadListAItemSucceeded, ReadListItemFailed);
}
function ReadListAItemSucceeded(sender, args) {
var listAItemsCollection = listAItems.getEnumerator();
while (listAItemsCollection.moveNext()) {
var listAItem = listAItemsCollection.get_current();
//do something with each listItem
}
}
function ReadListItemFailed(sender, args) {
alert('Request failed. ' + args.get_message() + '\n' + args.get_stackTrace());
}
我最终复制了所有代码以使其运行,但这不是可行的方法,因为它只是一团糟 - 必须有一个实际的设计。
var listAItems;
var listBItems;
$(document).ready(function() {
ExecuteOrDelayUntilScriptLoaded(LoadChartData, "sp.js");
});
function LoadChartData() {
context = SP.ClientContext.get_current();
var listA = context.get_web().get_lists().getByTitle("ListA");
var camlQuery = SP.CamlQuery.createAllItemsQuery();
this.listAItems = listA.getItems(camlQuery);
context.load(listAItems);
context.executeQueryAsync(ReadListAItemSucceeded, ReadListItemFailed);
context2 = SP.ClientContext.get_current();
var listB = context.get_web().get_lists().getByTitle("ListB");
var camlQuery2 = SP.CamlQuery.createAllItemsQuery();
this.listBItems = listB.getItems(camlQuery2);
context2.load(listBItems);
context2.executeQueryAsync(ReadListBItemSucceeded, ReadListItemFailed);
}
function ReadListAItemSucceeded(sender, args) {
var listAItemsCollection = listAItems.getEnumerator();
while (listAItemsCollection.moveNext()) {
var listAItem = listAItemsCollection.get_current();
//do something with each listItem
}
}
function ReadListBItemSucceeded(sender, args) {
var listBItemsCollection = listBItems.getEnumerator();
while (listBItemsCollection.moveNext()) {
var listBItem = listBItemsCollection.get_current();
//do something with each listItem
}
}
function ReadListItemFailed(sender, args) {
alert('Request failed. ' + args.get_message() + '\n' + args.get_stackTrace());
}
为什么我要查询多个列表是显而易见的,查询同一列表的原因是提供不同的CAML表达式,例如不同的条件。
非常感谢您提前!
答案 0 :(得分:5)
异步概念并不困难,你必须思考:"做到这一点,当你完成调用这个函数"时,这个概念就应用于变量的可见性,在javascript中这称为closure
在你的代码中你可以这样做(警告我没有测试下面的代码)
$(document).ready(function() {
ExecuteOrDelayUntilScriptLoaded(loadChartData, "sp.js");
});
function loadChartData() {
loadListData("listA", listASuccess, globalError);
loadListData("listB", listBSuccess, globalError);
}
function loadListData(listName, onSuccess, onFail) {
context = SP.ClientContext.get_current();
var list = context.get_web().get_lists().getByTitle(listName);
var camlQuery = SP.CamlQuery.createAllItemsQuery();
var listItems = list.getItems(camlQuery);
context.load(listAItems);
context.executeQueryAsync(
function(sender, args) {
// listItem is defined on same closure, you do not need to declare globally
onSuccess(listItems);
},
onFail
);
}
function listASuccess(data) {
var listAItemsCollection = data.getEnumerator();
while (listAItemsCollection.moveNext()) {
var listAItem = listAItemsCollection.get_current();
//do something with each listItem
}
// You can use also forEach like this
// data.forEach(function(listItem) {
// //do something with each listItem
// });
}
function listBSuccess(data) {
var listBItemsCollection = data.getEnumerator();
while (listBItemsCollection.moveNext()) {
var listBItem = listBItemsCollection.get_current();
//do something with each listItem
}
// You can use also forEach like this
// data.forEach(function(listItem) {
// //do something with each listItem
// });
}
function globalError(sender, args) {
alert('Request failed. ' + args.get_message() + '\n' + args.get_stackTrace());
}