Javascript 无法在Angular2中进行http服务调用?
嗨,我在Angular 5开发web应用程序。我正在生成树状结构。我跟在后面。我正在进行API调用以动态获取数据并显示为树。我的方法适用于静态数据,但不适用于在进行http调用后获取动态数据Javascript 无法在Angular2中进行http服务调用?,javascript,json,angular,typescript,http,Javascript,Json,Angular,Typescript,Http,嗨,我在Angular 5开发web应用程序。我正在生成树状结构。我跟在后面。我正在进行API调用以动态获取数据并显示为树。我的方法适用于静态数据,但不适用于在进行http调用后获取动态数据 public string ChildTranslator(){ return this.nodeservice.GetChildNodes(); } 下面的代码使用静态数据 asyncChildren = [ { name: 'child1', hasChild
public string ChildTranslator(){
return this.nodeservice.GetChildNodes();
}
下面的代码使用静态数据
asyncChildren = [
{
name: 'child1',
hasChildren: true
}, {
name: 'child2'
}
];
getChildren(node: any) {
const newNodes = this.asyncChildren.map((c) => Object.assign({}, c));
return new Promise((resolve, reject) => {
setTimeout(() => resolve(newNodes), 1000);
});
}
public string ChildTranslator(){
return this.nodeservice.GetChildNodes();
}
在上面的代码中,当我调用服务而不是this.asyncChildren时,我的代码将无法工作。下面是我的实现
getChildren(node: any) {
const newNodes = this.ChildTranslator().map((c) => Object.assign({}, c));
return new Promise((resolve, reject) => {
setTimeout(() => resolve(newNodes), 1000);
});
}
public string ChildTranslator(){
return this.nodeservice.GetChildNodes();
}
只要有子节点,就会调用上述方法。因此,我不是调用this.asyncChildren,而是调用this.ChildTranslator方法,该方法进行http服务调用,获取JSON并将数据转换为所需格式。下面是ChildTranslator方法的实现
public string ChildTranslator(){
this.nodeservice.GetChildNodes().subscribe(data=>{
this.asyncChildren= this.transformer(data);
return this.asyncChildren;
});
}
public string ChildTranslator(){
return this.nodeservice.GetChildNodes();
}
变压器代码
public string transformer(data:any){
this.asyncChildren=[];
let results=data;
for (const key in results) {
if (results[key] instanceof Array) {
const containerTyp2 = {name: '', hasChildren: false,};
containerTyp2.name = key;
containerTyp2.hasChildren = true;
this.asyncChildren.push(containerTyp2);
} else {
const object = {name: ''};
const containerTyp1 = {name: '', children: []};
object.name = results[key];
containerTyp1.name = key;
containerTyp1.children.push(object);
this.asyncChildren.push(containerTyp1);
}
this.tree.treeModel.update();
}
return this.asyncChildren;
}
public string ChildTranslator(){
return this.nodeservice.GetChildNodes();
}
上面的代码会弹出下面的错误
public string ChildTranslator(){
return this.nodeservice.GetChildNodes();
}
无法读取未定义的属性“map”
public string ChildTranslator(){
return this.nodeservice.GetChildNodes();
}
有人能帮我做这件事吗?我可以知道我在上面的代码中遗漏了什么吗?任何帮助都将不胜感激。多谢各位 试试这个:
getChildren(node: any) {
return new Promise((resolve, reject) => {
this.nodeservice.GetChildNodes().subscribe(data=>{
this.asyncChildren= this.transformer(data);
const newNodes = this.asyncChildren.map((c) => Object.assign({}, c));
setTimeout(() => resolve(newNodes), 1000);
});
});
}
public string ChildTranslator(){
return this.nodeservice.GetChildNodes();
}
更改
getChildren
方法如下:
getChildren(node: any) {
const newNodes = this.ChildTranslator().subscribe(data=>{
this.asyncChildren= this.transformer(data);
this.asyncChildren.map((c) => Object.assign({}, c));
return new Promise((resolve, reject) => {
setTimeout(() => resolve(newNodes), 1000);
});
});
}
public string ChildTranslator(){
return this.nodeservice.GetChildNodes();
}
另外,从ChildTranslator
方法返回如下值:
public string ChildTranslator(){
return this.nodeservice.GetChildNodes();
}
ChildTranslator()
不返回值。@Niranjan Anytime但唯一的问题是它一直在调用getChildren方法数千次。@Niranjan什么一直在调用getChildren
?this.asyncChildren=this.transformer(数据);这是我一直在打电话。我已经发布了上面的实现。@Niranjan您在哪里调用getChildren
方法?