爲什麼在我的if語句中我的單選按鈕有「不在當前上下文中」的錯誤？

Question

我的單選按鈕沒有出現，當我在if語句輸入它們它給了我：

命名爲「活動」並沒有出現在這個當前上下文。

（HTML）

<div class="option"> 
    <input id="Activity1" value="Activity1" name="Activity" checked="" type="radio" /> 
    <label for="Activity1">Light Activity <br />(Moderate excercise, <br /> but inactive at work)</label> 
</div> 
<div class="option"> 
    <input id="Activity2" value="Activity2" name="Activity" checked="" type="radio" /> 
    <label for="Activity2">Moderate Activity <br />(Intense excercise, <br /> but inactive at work)</label> 
</div> 
<div class="option"> 
    <input id="Activity3" value="Activity3" name="Activity" checked="" type="radio" /> 
    <label for="Activity3">Very Active <br />(Moderate excercise,<br /> active job)</label> 
</div> 
<div class="option"> 
    <input id="Activity4" value="Activity4" name="Activity" checked="" type="radio" /> 
    <label for="Activity4">Extremely Active <br />(Intense excercise, <br /> active job)</label> 
</div> 

---

（C＃）

if (Activity.Activity1.checked) 
{ 
    //initialise the activity levels 
    //take uBW and aL and multiply and put sum in usercarb 
    activityLevel = 11; 
    UserCal = (UserBodyWeight * activityLevel); 
} 
else if (Activity.Activity2.checked) 
{ 
    activityLevel = 12; 
    UserCal = (UserBodyWeight * activityLevel);  
} 

Answer 1

您可以設置runat="server"使這些元素可編程，添加runat="server"屬性的HTML元素指示元素應該被視爲服務器控件：

<input id="Activity1" runat="server" value="Activity1" name="Activity" checked="" type="radio" /> 

或使用asp:RadioButton控制如果你想在後面的代碼中訪問它。