我正在尝试在Angular 2中创建一个显示服务数据的组件。该服务基本上从用户输入一些json文件后加载一些数据。我一直试图让组件更新，但它似乎没有认识到更改，除非我从我的服务提交事件后调用zone.run（）。组件的代码如下......
@Component({
selector: 'assess-asset-group',
directives: [AssetComponent, AssetHeaderComponent, NgFor, NgIf],
template: `
<div *ngIf="assetService.schema != null">
<div class="asset-group" *ngFor="#assetTypeName of assetService.schema.assetTypeNames">
<div class="asset-type-title"><span>{{assetService.schema.assetTypes[assetTypeName].name}}s</span></div>
<table class="asset-group-table" cellpadding=0 cellspacing=0>
<thead>
<tr assess-asset-header [assetType]="assetService.schema.assetTypes[assetTypeName]"></tr>
</thead>
<tbody>
<tr assess-asset *ngFor="#asset of assetService.assetsForType(assetTypeName)" [asset]="asset"></tr>
</tbody>
</table>
<button class="new-asset-btn" (click)="assetService.addAsset(assetTypeName)">New</button>
</div>
</div>`,
providers: [provide(AssetService, {useValue: injector.get(AssetService)})]
})
export class AssetGroupComponent {
public assetService: AssetService;
public zone: NgZone;
constructor( @Inject(AssetService) assetService: AssetService, zone: NgZone) {
this.assetService = assetService;
this.zone = zone;
}
ngOnInit() {
this.assetService.proejectLoadedEmitter.subscribe((e) => { this.zone.run(() => { }) });
}
ngOnDestroy() {
this.assetService.proejectLoadedEmitter.unsubscribe();
}
}
我做错了什么或者这是我需要做什么才能更新视图？
UPDATE - AssetService Class
@Injectable()
export class AssetService{
public assets: Assets.Asset[] = [];
public assetTypeDefinitions: any = null;
public schema: Schema = null;
public assetsAsObj: any = null; // Asset file loaded as object
@Output() proejectLoadedEmitter: EventEmitter<any> = new EventEmitter();
constructor(){
}
public loadProject(config: Project){
// Load schema
// populate AssetTypeDefinitions as object keyed by type
let data = fs.readFileSync(config.schemaPath, 'utf8');
if (!data) {
utils.logError("Error reading schema file");
return;
}
let struc = fs.readFileSync(config.structurePath, 'utf8');
if (!struc) {
utils.logError("Error reading structure file");
return;
}
this.schema = new Schema(JSON.parse(data), struc);
this.readAssets(config.assetFilePath);
}
/**
* @brief Adds a new asset to the assets array
* @details Constructs the asset based on the type and populates
* its fields with appropreiate default values
*
* @param type The type of the asset - specified in the schema
*/
public addAsset(type: string): void {
// Need to make sure there is a loaded type definition for the specified type
if(!this.schema.assetTypes.hasOwnProperty(type)){
utils.logError("Error occured during call to addAsset - type \"" + type + "\" is not specified in the loaded schema");
return;
}
// Creeate a new asset object - passing in the type definition from the schema
this.assets.push(new Assets.Asset(this.schema.assetTypes[type]));
}
/**
* Write the current assets to a file using the specified format
* If the outputPasth isn't specied try and load it from the project.json file
*/
public writeAssets(format:AssetWriteFormat, outputPath?: string) : void {
var outStructureStr = this.schema.structureStr;
// insert AS properties from schema into output assets
this.schema.properties.forEach(prop => {
outStructureStr = outStructureStr.replace(new RegExp('"' + prop +'"', 'i'), this.retriveValueForSchemaProperty(prop));
});
fs.writeFileSync("C:/Projects/Assess/assets.json", outStructureStr);
}
public readAssets(inputPath?: string) : void{
let assetsStr = fs.readFileSync(inputPath, 'utf8');
let strucToAssetMap = {};
let strucObj = JSON.parse(this.schema.structureStr);
this.schema.properties.forEach(p => {
strucToAssetMap[p] = this.findValueInObject(strucObj, p).reverse();
});
// @TODO Load custom properties
let assetsObj = JSON.parse(assetsStr);
var c = null;
strucToAssetMap["AS_ASSETS"].forEach(p => {
if(c == null){
c = assetsObj[p];
}else{
c = c[p];
}
});
c.forEach((asset) => {
let a:Assets.Asset = new Assets.Asset(this.schema.assetTypes[asset.type], asset);
this.assets.push(a);
});
console.log(this.assets);
this.proejectLoadedEmitter.emit(null);
}
public assetsForType(type:string): Assets.Asset[]{
var ret: Assets.Asset[] = [];
for(let idx in this.assets){
if(this.assets[idx].definition.type === type){
ret.push(this.assets[idx]);
}
}
return ret;
}
public retriveValueForSchemaProperty(property: string) : string{
if(AS_SchemaTypes.indexOf(property) != -1){
switch (property) {
case "AS_ASSETS":
let outAssets = [];
this.assets.forEach((asset) => {
let outAsset = {};
outAsset["type"] = asset.definition.type;
for (let key in asset.fields) {
outAsset[key] = asset.fields[key].value;
}
outAssets.push(outAsset);
});
return JSON.stringify(outAssets, null, "\t");
}
}else{
// @TODO Retrive custom properties
return '"DDDDDD"';
}
return "";
}
public findValueInObject(obj: any, property: string, path: any[] = []): any[] {
for(let x in obj){;
let val = obj[x];
if (val == property){
path.push(x);
return path;
}
else if(val != null && typeof val == 'object'){
let v = this.findValueInObject(val, property, path);
if(v != null){
path.push(x);
return path;
}
}
}
return null;
}
}
答案 0 :(得分：12)
这需要了解您正在使用的:NERDTree的内部运作方式。
Angular在其区域内运行组件的代码，其中大多数异步API（AssetService，addEventListener，...）都被修补，因此区域可以在发生此类异步回调时通知Angular。这是Angular运行变化检测的时候。
如果您在Angular之外初始化setTimeout或通过其他方式AssetService执行Angulars区域之外的代码，则Angular不会收到有关发生的异步回调的通知，并且不会运行更改检测
使用AssetService，您明确地在Angulars区域内执行代码，然后运行更改检测。
答案 1 :(得分：0)
是否可能是由于在您的视图中引用assetService，参数而不是this.assetService引起的？也许这会导致Angular的变化检测在没有调用zone.run（）的情况下被触发。