breeze fetch meta data if not present

问题

I have an angular / breeze / webapi app which works great except if I refresh a page which has a EntityQuery to return one entity. It then complains that the metadata is not available as the entityquery does not trigger a metadata fetch, unlike a standard query.

If we have reached the page from a previous angular page which has fired a standard breeze query then the metadata is already there and we have no problem.

So question is, how do I check the metadata exists and trigger the metadata call if it is not already done?

Many thanks for any help you can give me.

回答1:

Try something like this:

function fetchMetadata() {
    var manager = new breeze.EntityManager("api/breeze");
    if (manager.metadataStore.isEmpty()) {
        return manager.fetchMetadata();
    }

    return Q.resolve();
}

function start() {
     fetchMetadata().then(function () {
            // Metadata fetched.
            // Do something here.
     });
}

来源：https://stackoverflow.com/questions/19245790/breeze-fetch-meta-data-if-not-present