CS50 金融 - 卖出（遍历下拉菜单）

Question

我正在网页上实现下拉菜单。在我的控制器代码中，我从 sqlite 数据库中获取数据并将其存储在一个名为“portfolio”的变量中。然后我用 Jinja 在我的 html 页面上迭代它。我在另一页上成功地遵循了同样的过程。唯一的区别是该信息显示在 table 而不是下拉菜单中。我怀疑有关将项目存储在“选项值”标签中的问题给我造成了问题。

任何人都可以帮助指出正确的方向吗？谢谢

My problem: no stocks displaying in dropdown menu

@app.route("/sell", methods=["GET", "POST"])
@login_required
def sell():
"""Sell shares of stock"""

# If a form is submitted
if request.method == "POST":
    symbol = request.form.get("symbol")
    shares_to_sell = int(request.form.get("shares"))

    # Access user's stock info
    portfolio = db.execute("SELECT symbol, SUM(shares) AS shares FROM purchases WHERE users_id = ? GROUP BY symbol", session["user_id"])
    for stock in portfolio:
        folio_symbol = stock["symbol"]
        shares_owned = int(stock["shares"])

        # Ensure stock is selected
        if not symbol:
            return apology("Must select a stock to sell", 403)

        # Ensure user owns that stock
        if symbol != folio_symbol:
            return apology("Can only sell stocks you own", 403)

        # If no shares selected
        if shares_to_sell < 1:
            return apology("Must select a number of shares to sell", 403)

        # If user does not own enough shares
        if shares_owned < shares_to_sell:
            return apology("User does not own enough shares to sell", 403)

        # Subtract shares sold from purchases table
        db.execute("UPDATE purchases SET shares = ? WHERE users_id = ?", shares_owned-shares_to_sell, session["user_id"])

        # Adjust cash in users table
        users = db.execute("SELECT * FROM users WHERE id = ?", session["user_id"])
        cash = users[0]["cash"]

        stock_info = lookup(symbol)
        sell_amt = shares_to_sell*stock_info["price"]

        db.execute("UPDATE users SET cash = ? WHERE id = ?", cash+sell_amt, session["user_id"])

        flash("Sold!")
        return redirect("/", portfolio=portfolio, stock=stock)

else:
    return render_template("sell.html")

HTML 页数：

{% extends "layout.html" %}

{% block title %}
    Sell Stocks
{% endblock %}

{% block main %}
    <h2>Sell Stocks</h2>
    <br>
    <p>Offload your shares below.</p>
    <br>
    <form action="/sell" method="post">
        <div class="form-group">
            <select class="form-control" name="symbol">
                <option disabled selected value>Stock</option>
                {% for stock in portfolio %}
                    <option value="{{ stock.folio_symbol }}">{{ stock.folio_symbol }}</option>
                {% endfor %}
            </select>
        </div>
        <div class="form-group">
            <input class="form-control" name="shares" placeholder="Shares" type="text">
        </div>
        <button class="btn btn-primary" type="submit">Sell</button>
    </form>
{% endblock %}

Answer 1

已解决：我忘记在 GET 条件下获取我的数据库信息。因此，下拉列表未填充，因为在该条件下没有可用数据来填充它。

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