无法使用Flask从下拉列表中在python中选择值 [英] Unable to get value selected in python from a dropdown using Flask
问题描述
这个问题可能是重复的，但我已经检查了所有此类相关问题的答案，但无法解决.
This question could be a duplicate but I have checked all the answers of such related questions and I haven't been able to solve it.
我正在尝试从包含数字的下拉菜单中获取值.然后，我想将数字与一个值进行比较，并根据比较结果显示文本.
I am trying to get the value from a dropdown menu which consists of numbers. Then I want to compare the numbers with a value and display a text based on the comparison.
例如
if value_selected_from_dropdown >3
display text
我无法显示文本，甚至无法打印所选选项的值.
I am unable to get the text to display or even print the value of the option selected.
这是python文件web_plants.py
Here is the python file, web_plants.py
from flask import Flask, render_template,request, redirect, url_for
app = Flask(__name__)
def template(title = "HELLO!", text = ""):
templateDate = {
'text' : text
}
return templateDate
@app.route("/threshold", methods=['POST'])
def threshold():
tvalue= (request.form.get['tvalue']) #get value from dropdown
msg= ""
if tvalue>3:
msg= "rating above 3"
templateData = template(text = msg) #display text using template()
#templateData = template(text = tvalue) #tried to print the value selected
return render_template('index.html', **templateData)
if __name__ == "__main__":
app.run(host='0.0.0.0', port=80, debug=True)
index.html:
index.html:
<!DOCTYPE HTML>
<html>
<head>
<link rel="stylesheet" type="text/css" href="{{ url_for('static',filename='style.css')}}" />
</head>
<body>
<h2> {{ text }} </h2>
<form action= "{{ url_for('threshold') }}" method="post>"
<p>
<select name= 'tvalue'>
<option value="10">10</option>
<option value="11">11</option>
<option value="15">15</option>
<option value="2">2</option>
<option value="1">1</option>
</select>
</p>
</form>
</body>
</html>
推荐答案
有几种方法可以实现此目的.您可以为模板本身提供逻辑，也可以在function threshold中添加逻辑.
There are several ways to achieve this. Either you can give logic to the template itself or you can add the logic in the function threshold.
index.html
<h2> {{text}} </h2>
<form action= "{{ url_for('threshold') }}" method="POST">
<select name= 'tvalue'>
{% for tvalue in tvalues %}
{% if selected_tvalue == tvalue %}
<option value="{{ tvalue }}" selected='selected'>{{ tvalue }}</option>
{% else %}
<option value="{{ tvalue }}" >{{ tvalue }}</option>
{% endif %}
{% endfor %}
</select>
<input type="submit" value="Submit" />
</form>
或
{% if selected_tvalue > 3 %}
<h2> Selected value is greater than 3 </h2>
{% else %}
<h2> Selected value is less than or equal to 3 </h2>
{% endif %}
<form action= "{{ url_for('threshold') }}" method="POST">
<select name= 'tvalue'>
{% for tvalue in tvalues %}
{% if selected_tvalue == tvalue %}
<option value="{{ tvalue }}" selected='selected'>{{ tvalue }}</option>
{% else %}
<option value="{{ tvalue }}" >{{ tvalue }}</option>
{% endif %}
{% endfor %}
</select>
<input type="submit" value="Submit" />
</form>
server.py
def template(title = "HELLO!", text = ""):
templateDate = {
'text' : text,
'tvalues' : getTValues(),
'selected_tvalue' : -1
}
return templateDate
def getTValues():
return (10, 11, 15, 2, 1)
@app.route("/threshold", methods=['POST', 'GET'])
def threshold():
tvalue= -1 #default value
msg = ''
if request.method == "POST":
tvalue = int(request.form['tvalue'])
if tvalue> 3:
msg= "rating above 3"
#generating template data
templateData = template(text = msg)
templateData['selected_tvalue'] = tvalue
return render_template('index.html', **templateData)
然后在路径/threshold中访问您的表单.希望对您有帮助.
Then access your form at path /threshold. I hope it helps.
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