Javascript 在typescript中将json对象转换为类类型数组时出错

我从服务中获取json对象，我想迭代到这个json对象并填充类类型的数组。 下面是调用该服务的代码

 public GetMapData(): Observable<Response> {
    var path = 'http://my.blog.net/blog.php?type=trendingDestiny';



    return this.http.get(path)
        .map((response: Response) => {
            if (response.status === 204) {
                return undefined;
            } else {
                return response.json();
            }
        });

}
self.blogapi.GetMapData().subscribe(
        x => {
            this.MapData = x;
            console.log("MapData", this.MapData);
        });

下面是typescript代码

this.MapData.forEach(map => {
        this.Mapdatalist.push({
            postid: map.post_id,
            regionname: map.region_name,
            longitude: map.longitude

        });
    });

或者我也试过了

for (let data of this.MapData)
    {
        console.log("error",data);

    }

但什么都不管用。这给了我错误

错误类型错误：无法读取未定义的属性“forEach”

---

请帮助解决问题。

请检查是否已将响应分配给“this.MapData”。我已经创建了相同的场景，它正在工作。可能是“this.MapData”未正确声明和定义。

this.MapData

未定义。您如何从服务获取此json对象？这段代码是什么样子的？@Shubham this.mapdata在html中使用ngfor时有数据。this.mapdata或this.mapdata？@C.jacking尝试在控制台中记录

this.mapdata

，并检查您得到了什么。@C.jacking请使用jquery库获取$。每个函数我也做了与您相同的操作，我也可以在控制台中看到this.MapData，但它仍然给了我一个错误。我可以进一步将这个数组创建为json吗？

var array= [
{
    "post_id": 77,
    "post_title": "Delhi",
    "post_content": "DelhiDelhiDelhi",
    "post_date": "2017-07-24 11:47:08",
    "imageurl": false,
    "cat_name": [
        {
            "term_id": 7,
            "name": "FOODIE",
            "slug": "foodie",               
            "category_parent": 0
        }
    ],
    "longitude": "75.857849",
    "latitude": "33.888586",
    "region_name": "Asia"
},
{
    "post_id": 75,
    "post_title": "Goa",
    "post_content": "this is goa",
    "post_date": "2017-07-24 11:03:59",
    "imageurl": false,
    "cat_name": [
        {
            "term_id": 7,
            "name": "FOODIE",
            "slug": "foodie",               
            "category_parent": 0
        }
    ],
    "longitude": "75.857849",
    "latitude": "33.888586",
    "region_name": "Asia"
}];
//console.log(array);
var mapdata = [];
$.each(array,function(i,v){
 mapdata.push({"postid":v.post_id,"regionname":v.region_name,"longitude":v.longitude});
})
console.log(mapdata);

var array= [
{
    "post_id": 77,
    "post_title": "Delhi",
    "post_content": "DelhiDelhiDelhi",
    "post_date": "2017-07-24 11:47:08",
    "imageurl": false,
    "cat_name": [
        {
            "term_id": 7,
            "name": "FOODIE",
            "slug": "foodie",               
            "category_parent": 0
        }
    ],
    "longitude": "75.857849",
    "latitude": "33.888586",
    "region_name": "Asia"
},
{
    "post_id": 75,
    "post_title": "Goa",
    "post_content": "this is goa",
    "post_date": "2017-07-24 11:03:59",
    "imageurl": false,
    "cat_name": [
        {
            "term_id": 7,
            "name": "FOODIE",
            "slug": "foodie",               
            "category_parent": 0
        }
    ],
    "longitude": "75.857849",
    "latitude": "33.888586",
    "region_name": "Asia"
}];
//console.log(array);
var mapdata = [];
$.each(array,function(i,v){
 mapdata.push({"postid":v.post_id,"regionname":v.region_name,"longitude":v.longitude});
})
console.log(mapdata);