[英]angular 2 typescript calling function
Please Check the below code. 请检查以下代码。 I am working on angular 2
generated by "Angular2 CLI" first time with the typescript . 我的工作angular 2
由“Angular2 CLI”第一次与打字稿生成。 and i have been having an issue on calling class function inside anonymous function . 我一直在匿名函数内部调用类函数时遇到问题。
For Example i want to call readFile()
function inside showDialog()
例如我想在showDialog()
调用readFile()
函数
What am i thinking! 我在想什么! wrong~ 错〜
Sorry For my English. 对不起我的英语不好。
import {Injectable} from '@angular/core';
import {Observable} from "rxjs";
import "rxjs/Rx";
@Injectable()
export class SelectFileService {
ImageExtensions: string[] = ['jpg', 'jpeg', 'png', 'gif'];
constructor() {
}
public showDialog(): Observable<string[]> {
return Observable.create((observer) => {
dialog.showOpenDialog({
properties: ['multiSelections'],
filters: [
{name: 'Images', extensions: this.ImageExtensions}
]
}, function (fileNames) {
if (fileNames === undefined) {
observer.error("ERROR");
return;
} else {
observer.next(fileNames);
observer.complete();
//Tried Below and not working
// this.readFile(fileNames[0]);
// Also tried java type
// SelectFileService.readFile(fileNames[0]);
}
});
});
}
public readFile(filePath: string): Observable<string> {
return Observable.create((observer) => {
fs.readFile(filePath, 'utf-8', function (err, data) {
if (err) {
observer.error(err.message);
}
observer.next(data);
observer.complete();
});
});
}
}
In Component: 在组件中:
this.selectfileservice.showDialog().subscribe(x => console.log(x))
Your function expression doesn't preserve the enclosing this
. 您的函数表达式不会保留this
。 Use an arrow function instead: 改用箭头功能:
return Observable.create((observer) => {
dialog.showOpenDialog({
properties: ['multiSelections'],
filters: [
{name: 'Images', extensions: this.ImageExtensions}
]
}, (fileNames) => { // <---- here ----
if (fileNames === undefined) {
observer.error("ERROR");
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