Question

我有一个Visual Studio C＃WinForms应用程序，其中必须评估布尔值以确定程序接下来会做什么，

用于抛出消息框或执行功能。问题是当布尔值计算为

时它会同时执行

真。

以下是代码：

private void btnNextQuestion_Click(object sender, EventArgs e)
{
    if (QuestionNeedsSaving == true)
    {
        QuestionNeedsSaving = false;
        MessageBox.Show("You have made changes to this question." + "\r\n" + "\r\n" + "Click the Update Question button to " + "\r\n" + "Save changes or the changes will be lost.", "OOPS!", MessageBoxButtons.OK, MessageBoxIcon.Warning);
    }
    else if (QuestionNeedsSaving == false)
        GoToNextQuestion();
}

如果布尔值“QuestionNeedsSaving”为true，则将其设置为false并抛出一个消息框。否则，如果“QuestionNeedsSaving”为false，则调用函数“GoToNextQuestion”。

问题是如果“QuestionNeedsSaving”为真，则执行消息框AND“GoToNextQuestion”。

“GoToNextQuestion”只应在“QuestionNeedsSaving”为假的情况下执行。

Answer 1

实际上主要的问题是QuestionNeedsSaving的常量状态，它总是通过if条件进行，并且更好地在其他地方做出QuestionNeedsSaving值的决定：

    private void btnNextQuestion_Click(object sender, EventArgs e)
    {
        if (QuestionNeedsSaving == true)
        {
            MessageBox.Show("You have made changes to this question." + "\r\n" + "\r\n" + "Click the Update Question button to " + "\r\n" + "Save changes or the changes will be lost.", "OOPS!", MessageBoxButtons.OK, MessageBoxIcon.Warning);
        }
        else if (QuestionNeedsSaving == false)
            GoToNextQuestion();
    }

Answer 2

只需运行此代码，您就会知道在奇数按钮的情况下单击QuestionNeedSaving = true会给出Next Question消息，但是如果按钮单击，则单击QuestionNeedSaving = false来给出OOPS！消息，将永远不会相同。

using System;
using System.Drawing;
using System.Windows.Forms;
namespace boolDecission
{
    public partial class Form1 : Form
  {
    bool QuestionNeedsSaving = false;
    int x = 0;
    public Form1()
    {
        InitializeComponent();
    }

    private void btnNextQuestion_Click(object sender, EventArgs e)
    {
        x = x + 1;
        //even number will make QuestionNeedsSaving = false and odd            number will make QuestionNeedsSaving = true. 
        if (x % 2 == 1)
        {
            QuestionNeedsSaving = false;
        }
        else 
        {
            QuestionNeedsSaving = true;
        }
        if (QuestionNeedsSaving == true)
        {
            MessageBox.Show("You have made changes to this question." + "\r\n" + "\r\n" + "Click the Update Question button to " + "\r\n" + "Save changes or the changes will be lost.", "OOPS!", MessageBoxButtons.OK, MessageBoxIcon.Warning);
        }
        else if (QuestionNeedsSaving == false)
        {
            GoToNextQuestion();
        }
    }
    public void GoToNextQuestion()
       {
            MessageBox.Show("Next Question");
       }

    }
}

C＃布尔评估未按预期评估

2 个答案: