未触发 XMLHTTPRequest onReadyStateChange

Question

我正在实施 XMLHTTPRequest，但无法触发 onreadystatechange 功能。

请问如何解决？谢谢。

function DisableDuplicateModuleCreation(context) {
    debugger;
    var saveEvent = context.getEventArgs();
    var user_userid= Xrm.Page.getAttribute("user_userid").getValue();
    var req = new XMLHttpRequest();
    req.open("GET", Xrm.Page.context.getClientUrl() + "/api/data/v9.0/modules?$select=user_userid&$filter=user_userid eq '" + user_userid + "' and statecode eq eq", false);
    req.setRequestHeader("OData-MaxVersion", "4.0");
    req.setRequestHeader("OData-Version", "4.0");
    req.setRequestHeader("Accept", "application/json");
    req.setRequestHeader("Content-Type", "application/json; charset=utf-8");
    req.setRequestHeader("Prefer", "odata.include-annotations=\"*\",odata.maxpagesize=1");
    req.onreadystatechange = function () { //last stop of this code and jumps to the end without going into function
        if (this.readyState === 4) {
            req.onreadystatechange = null;
            if (this.status === 200) {
                var results = JSON.parse(this.response);
                alert("results.entities.length: " + results.entities.length);
                if (results.entities.length > 0) {
                    alert("Module failed to create due to an existing module for User ID " + user_userid + ". Please update the existing module.");
                    saveEvent.preventDefault();
                }
            } else {
                Xrm.Utility.alertDialog(this.statusText);
            }
        }
    };
} //jumps to end of code after => req.onreadystatechange = function () from above

Answer 1

您已经创建了var/objectreq但是您还没有发送这个对象，你错过了 req.send();

这是一个示例 XMLHttpRequest

var req = new XMLHttpRequest();
req.open("GET", Xrm.Page.context.getClientUrl() + "/api/data/v9.0/accounts?$select=address2_county&$filter=accountid eq 1234567899", false);
req.setRequestHeader("OData-MaxVersion", "4.0");
req.setRequestHeader("OData-Version", "4.0");
req.setRequestHeader("Accept", "application/json");
req.setRequestHeader("Content-Type", "application/json; charset=utf-8");
req.setRequestHeader("Prefer", "odata.include-annotations=\"*\"");
req.onreadystatechange = function() {
    if (this.readyState === 4) {
        req.onreadystatechange = null;
        if (this.status === 200) {
            var results = JSON.parse(this.response);
            for (var i = 0; i < results.value.length; i++) {
                var address2_county = results.value[i]["address2_county"];
            }
        } else {
            Xrm.Utility.alertDialog(this.statusText);
        }
    }
};
req.send();

如果我可以更进一步并建议，请尝试使用 Xrm.Webapi 来执行 webapi 请求。 Microsoft 强烈推荐使用 Xrm.Webapi

注意：Xrm.Webapi 是异步的，您可能希望使用 promise 使其像 Sync/or 等待您的请求完成一样工作

Xrm.WebApi.online.retrieveMultipleRecords("account", "?$select=address2_county&$filter=accountid eq 1234567899").then(
    function success(results) {
        for (var i = 0; i < results.entities.length; i++) {
            var address2_county = results.entities[i]["address2_county"];
        }
    },
    function(error) {
        Xrm.Utility.alertDialog(error.message);
    }
);

未触发 XMLHTTPRequest onReadyStateChange

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