jinja2.exceptions.UndefinedError：對象沒有屬性

Question

我正在嘗試創建一個庫存管理系統，我可以在其中通過表單（WTForms）創建/添加庫存，並將其顯示在單獨頁面的表格中。 目前，我被困在所述錯誤上。 我到處尋找答案無濟於事。 我應該通過“createGPU.html”添加庫存並被定向到“retrieveGPU.html”

單擊 createGPU 中的提交按鈕會導致 jinja2.exceptions.UndefinedError: 'GPUs.GPUs object' has no attribute 'GPUName'

主程序

from flask import Flask, render_template, request, redirect, url_for
from Forms import CreateGPUForm
import shelve, GPUs

@app.route("/createGPU", methods=['GET', 'POST'])
def createGPU():
    createGPUForm = CreateGPUForm(request.form)
    if request.method == 'POST' and createGPUForm.validate():
        gpuDict = {}
        db = shelve.open('storage.db', 'c')

        try:
            gpuDict = db['GPU']
        except:
            print('Error in retrieving GPUs from storage.db.')

        gpu = GPUs.GPUs(createGPUForm.GPUName.data, createGPUForm.GPUUnitPrice.data, createGPUForm.GPUStock.data,createGPUForm.GPUSales.data)
        gpuDict[gpu.get_GPUNo()] = gpu
        db['GPU'] = gpuDict
        db.close()

        return redirect(url_for('retrieveGPU'))
    return render_template('createGPU.html', form=createGPUForm)

if __name__ == '__main__':
    app.run()

@app.route('/retrieveGPU')
def retrieveGPU():
    gpuDict = {}
    db = shelve.open('storage.db', 'r')
    gpuDict = db['GPU']
    db.close()

    gpuList = []
    for key in gpuDict:
        gpu = gpuDict.get(key)
        gpuList.append(gpu)

    return render_template('retrieveGPU.html',gpuList=gpuList, count=len(gpuList))

創建GPU

{% extends "base.html" %}
{% block title %}GPU-Assist - Add Graphics Card{% endblock %}

{% block content %}
{% from "includes/_formhelper.html" import render_field %}

<h1 class="display-4">Add Graphics Card</h1>
  <form method="POST" action="">
    <div class="form-group">
      {{ render_field(form.GPUName, class="form-control") }}
    </div>
    <div class="form-group">
      {{ render_field(form.GPUStock, class="form-control") }}
    </div>
    <div class="form-group">
      {{ render_field(form.GPUUnitPrice, class="form-control")  }}
    </div>
    <div class="form-group">
      {{ render_field(form.GPUSales, class="form-control")  }}
    </div>
    <input type="submit" value="Submit" class="btn btn-primary"/>
  </form>



{% endblock %}

檢索GPU

{% extends "base.html" %}
{% block title %}GPU-Assist - View GPU-Cart{% endblock %}

{% block content %}
<h1 class="display-4">View GPU</h1>
<div>
  {% if count == 0 %}
  <p>No GPU in recorded in inventory.</p>
  {% elif count == 1 %}
  <p>There is 1 GPU recorded in the inventory.</p>
  {% else %}
  <p>There are {{ count }} GPUs recorded in the inventory.</p>
  {% endif %}
</div> <!--End of display number of users div-->

<div>
  <table class="table table-striped">
    <thead>
      <tr>
        <th>Name</th>
        <th>Stock</th>
        <th>Unit Price</th>
        <th>Sales</th>
        <th></th>
        <th></th>
      </tr>
    </thead>
    <tbody>
       {% for gpu in gpuList %}
      <tr>
        <td>{{ gpu.GPUName() }}</td>
        <td>{{ gpu.GPUStock() }}</td>
        <td>{{ gpu.GPUUnitPrice() }}</td>
        <td>{{ gpu.GPUSales() }}</td>
        <td><a href="/updateGPU/{{gpu.get_GPUNo()}}" class="btn btn-warning">Update</a></td>
        <td>
          <form action="" method="POST">
            <input type="submit" value="Delete" class="btn btn-danger">
          </form>
        </td>
      </tr>
    {% endfor %}

    </tbody>
  </table>
</div>
{% endblock %}

圖形處理器.py

class GPUs:
    countID = 0
    def __init__(self,GPUName,GPUStock,GPUUnitPrice,GPUSales):
        GPUs.countID += 1
        self.__GPUName = GPUName
        self.__GPUStock = GPUStock
        self.__GPUUnitPrice = GPUUnitPrice
        self.__GPUSales = GPUSales
        self.__GPUNo=GPUs.countID


    '''
    One obvious limitation it has is that every time you restart the web application, the countID resets to 0. 
    Once the countID resets, the next newly created Users’s userID will start from 1 again and overwrite any User 
    that previously had __userID = 1.  (Must figure out an alternative)
    '''
    #Getter or Accessor
    def get_GPUNo(self):
        return self.__GPUNo
    def get_GPUName(self):
        return self.__GPUName
    def get_GPUStock(self):
        return self.__GPUStock
    def get_GPUUnitPrice(self):
        return self.__GPUUnitPrice
    def get_GPUSales(self):
        return self.__GPUSales

    #Settor or Mutator
    def set_GPUNo(self, GPUNo):
        self.__GPUNo = GPUNo
    def set_GPUName(self, GPUName):
        self.__GPUName = GPUName
    def set_GPUStock(self, GPUStock):
        self.__GPUStock = GPUStock
    def set_GPUUnitPrice(self, GPUUnitPrice):
        self.__GPUUnitPrice = GPUUnitPrice
    def set_GPUSales(self, GPUSales):
        self.__GPUSales = GPUSales

Answer 1

Jinja2 處理時

    <td>{{ gpu.GPUName() }}</td>

它期望gpu將有一個名為GPUName的可調用成員函數。 你編碼的方式， get_GPUName是你想要的。

Pythonic 的方法是完全刪除 getter 和 setter，刪除雙下划線前綴，並讓模板直接用於命名實例變量。

    <td>{{ gpu.GPUName }}</td>