如何在选择更新相应的绑定值中具有 id（主键）值

Question

In a nutshell I want a select box populated with a domain with the option values being the id/primary key, and when the select is changed, I'd like the corresponding records' bound values updated.您可以在此处看到 Bureau_id() 确实发生了变化，但同一记录的名称或个人区域没有变化。我觉得这里有一个可观察的，但我使用了 map()，但我不知道如何利用它。在视图模型中，我还认为 id 参数可能对此有所帮助。

我还想知道是否有更好的方法来使用域来控制通过 id 编辑数据中的项目并更新与该 id 相关的域字段。想法是在单击值时显示选择，并在选择后返回文本。

$(function() {
	$.views.viewModels({
		Root: {
			getters: [
				{
					getter: "bureaus", 
					type: "Bureau"
				}
			]	
		},
		Bureau: {
			id: "bureau_id",
			getters: ["bureau_id","name","personal_area"]
		}
	});	

	data = {
		bureaus: [
			{  
		        "bureau_id":40,
		        "name":"Bureau of Emergency Communications",
		        "personal_area":1200
		    },
		    {  
				"bureau_id":30,
				"name":"Office of the City Attorney",
				"personal_area":1090
			}
		]

	} 

	domains = {
		"bureau":  [  
		 {  
		    "bureau_id":41,
		    "name":"Bureau of Development Services",
		    "personal_area":1210
		 },
		 {  
		    "bureau_id":40,
		    "name":"Bureau of Emergency Communications",
		    "personal_area":1200
		 },
		 {  
		    "bureau_id":39,
		    "name":"Bureau of Emergency Management",
		    "personal_area":1190
		 },
		 {  
		    "bureau_id":22,
		    "name":"Bureau of Environmental Services",
		    "personal_area":1010
		 },
		 {  
		    "bureau_id":42,
		    "name":"Bureau of Fire and Police Disability and Retirement Fund",
		    "personal_area":1230
		 },
		 {  
		    "bureau_id":43,
		    "name":"Bureau of Human Resources",
		    "personal_area":1240
		 },
		 {  
		    "bureau_id":45,
		    "name":"Bureau of Internal Business Services",
		    "personal_area":1260
		 },
		 {  
		    "bureau_id":36,
		    "name":"Bureau of Parks and Recreation",
		    "personal_area":1160
		 },
		 {  
		    "bureau_id":34,
		    "name":"Bureau of Planning and Sustainability",
		    "personal_area":1140
		 },
		 {  
		    "bureau_id":46,
		    "name":"Bureau of Revenue & Financial Services",
		    "personal_area":1275
		 },
		 {  
		    "bureau_id":44,
		    "name":"Bureau of Technology Services",
		    "personal_area":1250
		 },
		 {  
		    "bureau_id":49,
		    "name":"City Budget Office",
		    "personal_area":1320
		 },
		 {  
		    "bureau_id":31,
		    "name":"Office of City Auditor Mary Hull Caballero",
		    "personal_area":1100
		 },
		 {  
		    "bureau_id":26,
		    "name":"Office of Commissioner Amanda Fritz",
		    "personal_area":1050
		 },
		 {  
		    "bureau_id":29,
		    "name":"Office of Commissioner Chloe Eudaly",
		    "personal_area":1080
		 },
		 {  
		    "bureau_id":28,
		    "name":"Office of Commissioner Dan Saltzman",
		    "personal_area":1070
		 },
		 {  
		    "bureau_id":27,
		    "name":"Office of Commissioner Nick Fish",
		    "personal_area":1060
		 },
		 {  
		    "bureau_id":37,
		    "name":"Office of Community & Civic Life",
		    "personal_area":1170
		 },
		 {  
		    "bureau_id":48,
		    "name":"Office of Equity and Human Rights",
		    "personal_area":1310
		 },
		 {  
		    "bureau_id":24,
		    "name":"Office of Government Relations",
		    "personal_area":1030
		 },
		 {  
		    "bureau_id":47,
		    "name":"Office of Management and Finance",
		    "personal_area":1290
		 },
		 {  
		    "bureau_id":38,
		    "name":"Office of Mayor Ted Wheeler",
		    "personal_area":1180
		 },
		 {  
		    "bureau_id":30,
		    "name":"Office of the City Attorney",
		    "personal_area":1090
		 },
		 {  
		    "bureau_id":35,
		    "name":"Police Bureau",
		    "personal_area":1150
		 },
		 {  
		    "bureau_id":32,
		    "name":"Portland Bureau of Transportation",
		    "personal_area":1120
		 },
		 {  
		    "bureau_id":23,
		    "name":"Portland Fire & Rescue",
		    "personal_area":1020
		 },
		 {  
		    "bureau_id":25,
		    "name":"Portland Housing Bureau",
		    "personal_area":1040
		 },
		 {  
		    "bureau_id":33,
		    "name":"Portland Water Bureau",
		    "personal_area":1130
		 }
		]
	};

	let vm = $.views.viewModels.Root.map(data);
	$.templates('#root-tmpl').link('#content', vm, domains);
});

<!doctype html>
<html>
	<head>
		<script src="https://code.jquery.com/jquery-3.3.1.min.js"></script>
		<script src="https://www.jsviews.com/download/jsviews.min.js"></script>
		<script src="https://code.jquery.com/ui/1.12.1/jquery-ui.min.js"></script>
		<link href="https://code.jquery.com/ui/1.12.1/themes/base/jquery-ui.css" rel="stylesheet">
		<script src="https://www.jsviews.com/download/sample-tag-controls/jsviews-jqueryui-widgets.min.js"></script>

		<script id="root-tmpl" type="text/x-jsrender">
			<ul>
				{^{for bureaus() tmpl="#bureau-tmpl"}}
				{{/for}}
			</ul>
		</script>

		<script id="bureau-tmpl" type="text/x-jsrender">
			<li>
				{^{>name()}} ({^{>personal_area()}}) {^{>bureau_id()}}


				{^{selectmenu bureau_id() name="bureau_id" class="bureau-select"}}
					{^{for ~bureau}}
						<option data-link="value{:bureau_id}">{^{>name}} ({^{>personal_area}})</option>
					{{/for}}
				{{/selectmenu}}
			</li>
		</script>
	</head>
	<body>
		<div id="content"></div>	
	</body>
</html>

Answer 1

您当前的版本存在许多问题。一种是您正在将数据项从 domain.bureau[n] 克隆到 data.bureaus[n]。如果您选择不同的下拉项目，那么您需要将所选项目以某种方式克隆到 data.bureau。在值可能发生变化（即编辑、服务器数据等）的真实情况下，您似乎也很容易遇到一些数据完整性问题

无论如何，这里有一个建议的替代设计。 data.bureaus 被重命名为 data.selected，并且只有 selected_id 是对相应 Bureau_id 的查找。

域和当前 data.selected 都映射到 ViewModel 实例。注意这一行：

getSelectedBureau.depends = "selected_id";  

确保当 selected_id 更改时，以下内容也会更新：

{^{>selectedBureau()^name()}} ({^{>selectedBureau()^personal_area()}}) ...

$(function() {

$.views.viewModels({
Root: {
	getters: [
		{getter: "selected", type: "SelectedBureau"},
		{getter: "bureaus", type: "Bureau"}
	]
},
SelectedBureau: {
	getters: ["selected_id"],
	extend: {
		selectedBureau: getSelectedBureau,
		bureaus: function() {
			return vm.bureaus();
		}
	}
},
Bureau: {
	id: "bureau_id",
	getters: ["bureau_id","name","personal_area"]
}
});

function getSelectedBureau() { // lookup to find the corresonding bureau VM
let bureaus = vm.bureaus(),
	l = bureaus.length;
while (l--) {
	if (this.selected_id() === "" + bureaus[l].bureau_id()) {
		return bureaus[l];
	}
}
}

getSelectedBureau.depends = "selected_id"; // So selectedBureau() updates when selected_id changes

let data = {
selected: [
	{
		"selected_id":"40"
	},
	{
		"selected_id":"30"
	}
],
"bureaus": [
	{
		"bureau_id":41,
		"name":"Bureau of Development Services",
		"personal_area":1210
	},
	{
		"bureau_id":40,
		"name":"Bureau of Emergency Communications",
		"personal_area":1200
	},
	{
		"bureau_id":49,
		"name":"City Budget Office",
		"personal_area":1320
	},
	{
		"bureau_id":31,
		"name":"Office of City Auditor Mary Hull Caballero",
		"personal_area":1100
	},
	{
		"bureau_id":30,
		"name":"Office of the City Attorney",
		"personal_area":1090
	}
]
};

let vm = $.views.viewModels.Root.map(data);

$.templates('#root-tmpl').link('#content', vm);

});

<!doctype html>
<html>
<head>
<script src="https://code.jquery.com/jquery-3.3.1.min.js"></script>
<script src="https://www.jsviews.com/download/jsviews.min.js"></script>
<script src="https://code.jquery.com/ui/1.12.1/jquery-ui.min.js"></script>
<link href="https://code.jquery.com/ui/1.12.1/themes/base/jquery-ui.css" rel="stylesheet">
<script src="https://www.jsviews.com/download/sample-tag-controls/jsviews-jqueryui-widgets.min.js"></script>

<script id="root-tmpl" type="text/x-jsrender">
<ul>
{^{for selected() tmpl="#bureau-tmpl"/}}
</ul>
</script>

<script id="bureau-tmpl" type="text/x-jsrender">
<li>
{^{>selectedBureau()^name()}} ({^{>selectedBureau()^personal_area()}}) {^{>selected_id()}}

{^{selectmenu selected_id() name="bureau_id" class="bureau-select"}}
	{^{for bureaus()}}
		<option value="{{:bureau_id()}}">{{>name()}} ({{>personal_area()}})</option>
	{{/for}}
{{/selectmenu}}
</li>
</script>
</head>
<body>
<div id="content"></div>	
</body>
</html>