Question

如何通过main-page.js更改基于xml的textField的文本？我使用this.set("message", getMessage(this.counter));通过main-view-model.js更改值。但是当我在main-page.js中尝试它时，这种情况不起作用。这该怎么做？ :-)我需要解释一下我的主要问题。提前谢谢。

Answer 1

我假设你在谈论＆＃34; Hello World＆＃34;可以找到here的NativeScript应用程序。区别在于main-page.js是＆＃34; 背后的代码＆＃34; main-page.xml的注意事项（注意命名约定对于{N}进行匹配很重要）和main-view-model.js是一个单独的文件，已被分配为bindingContext到Page你可以看到here：

中navigatingTo事件中的main-page.xml

function onNavigatingTo(args) {
    /*
    This gets a reference this page’s <Page> UI component. You can
    view the API reference of the Page to see what’s available at
    https://docs.nativescript.org/api-reference/classes/_ui_page_.page.html
    */
    var page = args.object;

    /*
    A page’s bindingContext is an object that should be used to perform
    data binding between XML markup and JavaScript code. Properties
    on the bindingContext can be accessed using the {{ }} syntax in XML.
    In this example, the {{ message }} and {{ onTap }} bindings are resolved
    against the object returned by createViewModel().
    You can learn more about data binding in NativeScript at
    https://docs.nativescript.org/core-concepts/data-binding.
    */
    page.bindingContext = createViewModel();
}

为了在其代码隐藏文件中更改main-page.xml的Label（TextView）文本，您可以通过id（getViewById() example）或直接获取Label使用bindingContext（您的＆＃39; ViewModel＆＃39;）：

var createViewModel = require("./main-view-model").createViewModel;
var viewModel;

function onNavigatingTo(args) {
    var page = args.object;
    viewModel = = createViewModel();
    page.bindingContext = viewModel;
}

// Example with event handler for a 'tap' event of a Button
function onButtonTap(args) {
    viewModel.set("message", "New message set via code behind");
}

通过Telerik App Builder开发本机应用程序时，main-page.js和main-view.model.js有什么区别

1 个答案: