参数类型＆＃x27; productModel？＆＃x27;可以将参数类型分配给ProductModel＆＃x27;

发布于 2025-01-31 14:33:21 字数 767 浏览 1 评论 0原文

我正在制作一个Midel，以将产品图像，价格和名称上传到Firebase，然后我遇到此错误（参数类型'ProductModel？'无法分配到参数类型'ProductModel'。）。

    class ProductProvider with ChangeNotifier {
  List<ProductModel> pizzaProductList = [];
  ProductModel? productModel;

  fatchPizzaproductData() async {
   // List<ProductModel> newList = [];

    QuerySnapshot value =
        await FirebaseFirestore.instance.collection("PizzaProducts").get();

     pizzaProductList = value.docs.map((element) {
      return ProductModel(
        productImage: element.get("productImage"),
        productName: element.get("productName"),
        productPrice: element.get("productPrice"),
      );
    }).toList();
    
  }

  get getPizzaproductDataList {
    return pizzaProductList;
  }
}

原文

I'm making a midel to upload product image,price and name to firebase then i face this error (The argument type 'ProductModel?' can't be assigned to the parameter type 'ProductModel'.)

    class ProductProvider with ChangeNotifier {
  List<ProductModel> pizzaProductList = [];
  ProductModel? productModel;

  fatchPizzaproductData() async {
   // List<ProductModel> newList = [];

    QuerySnapshot value =
        await FirebaseFirestore.instance.collection("PizzaProducts").get();

     pizzaProductList = value.docs.map((element) {
      return ProductModel(
        productImage: element.get("productImage"),
        productName: element.get("productName"),
        productPrice: element.get("productPrice"),
      );
    }).toList();
    
  }

  get getPizzaproductDataList {
    return pizzaProductList;
  }
}

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属性 2025-02-07 14:33:21

问题是productModel是一种不可用的类型，而pizzaproduct是不可删除的 productmodel s的列表。

而不是在类上存储属性productModel，而是考虑从value.docs pizzaproduct 直接映射，并删除存储模型的中间步骤在productModel中：

class ProductProvider with ChangeNotifier {
  List<ProductModel> pizzaProduct = [];

  Future<void> fetchPizzaProductData() async {
    QuerySnapshot value =
        await FirebaseFirestore.instance.collection("PizzaProducts").get();

    pizzaProduct = value.docs.map((element) {
      return ProductModel(
        productImage: element.get("productImage"),
        productName: element.get("productName"),
        productPrice: element.get("productPrice"),
      );
    }).toList();

    // Since this is a ChangeNotifier, I'm assuming you might want to
    // notify listeners when `pizzaProduct` changes. Disregard this line
    // if that's not the case.
    notifyListeners();
  }
}

The problem is that productModel is a nullable type, whereas pizzaProduct is a List of non-nullable ProductModels.

Instead of storing a property productModel on your class, consider mapping directly from value.docs to pizzaProduct, and removing the intermediate step of storing the model in productModel:

class ProductProvider with ChangeNotifier {
  List<ProductModel> pizzaProduct = [];

  Future<void> fetchPizzaProductData() async {
    QuerySnapshot value =
        await FirebaseFirestore.instance.collection("PizzaProducts").get();

    pizzaProduct = value.docs.map((element) {
      return ProductModel(
        productImage: element.get("productImage"),
        productName: element.get("productName"),
        productPrice: element.get("productPrice"),
      );
    }).toList();

    // Since this is a ChangeNotifier, I'm assuming you might want to
    // notify listeners when `pizzaProduct` changes. Disregard this line
    // if that's not the case.
    notifyListeners();
  }
}

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