我正在开展一个测验项目，该项目还允许用户添加新问题。
我有一个数组列表，其中存储和检索问题以供显示。保存在数组列表中的每个对象包含5个字符串。
如何从数组列表中随机选择要在屏幕上显示的对象？我怎样才能将4个答案（作为单选按钮）混洗，以便每次在不同的位置出现正确的答案？
namespace quiz
{
public partial class Quiz : Form
{
private ArrayList Questionslist;
public Quiz(ArrayList list)
{
InitializeComponent();
Questionslist = list;
}
int index = 0;
private void Quiz_Load(object sender, EventArgs e)
{
//creating an object of class Question and copying the object at index1 from arraylist into it
Question q = (Question)Questionslist[index];
//to display the contents
lblQs.Text = q.Quest;
radioButtonA1.Text = q.RightAnswer;
radioButtonA2.Text = q.WrongAnswer1;
radioButtonA3.Text = q.WrongAnswer2;
radioButtonA4.Text = q.WrongAnswer3;
}
private int Score = 0;
private void radioButtonA1_CheckedChanged(object sender, EventArgs e)
{
//if checkbox is checked
//displaying text in separate two lines on messagebox
if (radioButtonA1.Checked == true)
{
MessageBox.Show("Well Done" + Environment.NewLine + "You Are Right");
Score++;
index++;
if (index < Questionslist.Count)
{
radioButtonA1.Checked = false;
radioButtonA2.Checked = false;
radioButtonA3.Checked = false;
radioButtonA4.Checked = false;
Quiz_Load(sender, e);
}
else
{
index--;
MessageBox.Show("Quiz Finished" + Environment.NewLine + "your Score is" + Score);
Close();
}
}
}
private void radioButtonA2_CheckedChanged(object sender, EventArgs e)
{
if (radioButtonA2.Checked == true)
{
MessageBox.Show("Sorry" + Environment.NewLine + "You Are Wrong");
Close();
}
}
private void radioButtonA3_CheckedChanged(object sender, EventArgs e)
{
if (radioButtonA3.Checked == true)
{
MessageBox.Show("Sorry" + Environment.NewLine + "You Are Wrong");
Close();
}
}
private void radioButtonA4_CheckedChanged(object sender, EventArgs e)
{
if (radioButtonA4.Checked == true)
{
MessageBox.Show("Sorry" + Environment.NewLine + "You Are Wrong");
Close();
}
}
}
}
这是课堂问题的代码
namespace quiz
{
[Serializable()]
public class Question : ISerializable
{
public String Quest;
public String RightAnswer;
public String WrongAnswer1;
public String WrongAnswer2;
public String WrongAnswer3;
public Question()
{
Quest = null;
RightAnswer=null;
WrongAnswer1=null;
WrongAnswer2=null;
WrongAnswer3=null;
}
//serialization function
public void GetObjectData(SerializationInfo info, StreamingContext context)
{
info.AddValue("Question", Quest);
info.AddValue("Right Answer", RightAnswer);
info.AddValue("WrongAnswer1",WrongAnswer1);
info.AddValue("WrongAnswer2",WrongAnswer2);
info.AddValue("WrongAnswer3",WrongAnswer3);
}
//deserializaton constructor
public Question(SerializationInfo info, StreamingContext context)
{
Quest = (String)info.GetValue("Question", typeof(String));
RightAnswer=(String)info.GetValue("Right Answer",typeof(String));
WrongAnswer1=(String)info.GetValue("WrongAnswer1",typeof(String));
WrongAnswer2=(String)info.GetValue("WrongAnswer2",typeof(String));
WrongAnswer3=(String)info.GetValue("WrongAnswer3",typeof(String));
}
}
}
答案 0 :(得分：1)
从ArrayList中选择一个随机字符串：
string randomPick(ArrayList strings)
{
return strings[random.Next(strings.Length)];
}
您可以考虑申请Question课程。这将包含问题的string Text成员（因为我认为Question.Question很傻，Question.Text在阅读时更有意义）。由于你提到了 ArrayList（不是因为我认为这是最好的解决方案），你可以将其中一个作为成员包含所有可能的答案。
创建问题时，您可以显示Question.Text，然后使用上述功能随机选择答案。然后在答案上使用RemoveAt(index)，以确保您不会重复答案。
答案 1 :(得分：1)
我会创建一个包含问题，正确答案和可能答案列表的Question课程，并提供按随机顺序返回可能答案的方法，并将猜测与正确答案进行比较。它可能看起来像这样：
class Question
{
String question;
String rightAnswer;
List<String> possibleAnswers = new ArrayList<String>();
public Question(String question, String answer, List<String> possibleAnswers)
{
this.question = question;
this.rightAnswer = answer;
this.possibleAnswers.addAll(possibleAnswers);
this.possibleAnswers.add(this.rightAnswer);
}
public List<String> getAnswers()
{
Collections.shuffle(possibleAnswers);
return possibleAnswers;
}
public boolean isCorrect(String answer)
{
return answer.equals(correctAnswer);
}
}
答案 2 :(得分：1)
根据Text属性，您知道哪一个是'正确'答案。一种方法是将答案存储在一个数组中，并在将数组分配给单选按钮之前对其进行洗牌：
// You're going to make questionList a List<Question> because if you like
// Right answers you know that ArrayList is Wrong.
Question q = questionList[index];
// You should move this next bit to the Question class
string[] answers = new string[]
{
q.RightAnswer,
q.WrongAnswer1,
q.WrongAnswer2,
q.WrongAnswer3
};
// Using the Fisher-Yates shuffle from:
// http://stackoverflow.com/questions/273313/randomize-a-listt-in-c-sharp
Shuffle(answers);
// Ideally: question.GetShuffledAnswers()
radioButtonA1.Text = answers[0];
radioButtonA2.Text = answers[1];
radioButtonA3.Text = answers[2];
radioButtonA4.Text = answers[3];
之后，您只需要一个单个单选按钮事件处理程序，它们共享：
private void radioButton_CheckedChanged(object sender, EventArgs e)
{
RadioButton rb = (RadioButton)sender;
Question q = questionList[index];
//if checkbox is checked
//displaying text in separate two lines on messagebox
if (rb.Checked && q.RightAnswer == rb.Text)
{
// Move your code to another method
// MessageBox.Show("Well Done" + Environment.NewLine + "You Are Right");
UserSelectedCorrectAnswer();
}
else if (rb.Checked)
{
// They checked the radio button, but were wrong!
// MessageBox.Show("Sorry" + Environment.NewLine + "You Are Wrong");
UserSelectedWrongAnswer();
}
}
答案 3 :(得分：0)
您应该将所有问题封装在一个类中。例如，创建一个名为Question的类。此类可以包含5个变量：String question，String answer1，String answer2，String answer3和String answer4。
将所有问题保存在数据库中或从文件中读取并在程序开头加载。
使用Random课程随机选择一个问题并“混乱”4个问题。
答案 4 :(得分：0)
这是一种可行的方法：
public List<string> Randomize(string[] numbers)
{
List<string> randomized = new List<string>();
List<string> original = new List<string>(numbers);
Random r = new Random();
while (original.Count > 0) {
int index = r.Next(original.Count);
randomized.Add(original[index]);
original.RemoveAt(index);
}
return randomized;
}
只是将它改编为字符串数组而不是int数组
答案 5 :(得分：0)
洗牌可能是一个标准问题，但我想这会起作用：
// Warning: Not a thread-safe type.
// Will be corrupted if application is multi-threaded.
static readonly Random randomNumberGenerator = new Random();
// Returns a new sequence whose elements are
// the elements of 'inputListOrArray' in random order
public static IEnumerable<T> Shuffle<T>(IReadOnlyList<T> inputListOrArray)
{
return GetPermutation(inputListOrArray.Count).Select(x => inputListOrArray[x]);
}
static IEnumerable<int> GetPermutation(int n)
{
var list = Enumerable.Range(0, n).ToArray();
for (int idx = 0; idx < n; ++idx)
{
int swapWith = randomNumberGenerator.Next(idx, n);
yield return list[swapWith];
list[swapWith] = list[idx];
}
}
如果您没有IReadOnlyList<T>（.NET 4.5），请使用IList<T>。传入的对象不会发生变异。
答案 6 :(得分：0)
private void Quiz_Load(object sender, EventArgs e)
{
displayQs();
}
private void displayQs()
{
Random _random = new Random();
int z = _random.Next(Questions.Count);
Question q = (Question)Questions[z];
Qslbl.Text = q.Quest;
DisplayAns(q, _random);
}
private void DisplayAns(Question q, Random _random)
{
int j = 0;
int[] array = new int[4];
for (int i = 0; j <= 3; i++)
{
int x = _random.Next(4);
x++;
if (array.Contains(x))
{
continue;
}
else
{
array[j] = x;
j++;
string answer = null;
if (j == 1)
answer = q.RightAnswer;
else if (j == 2)
answer = q.WrongAnswer1;
else if (j == 3)
answer = q.WrongAnswer2;
else if (j == 4)
answer = q.WrongAnswer3;
if (x == 1)
radioButton1.Text = answer;
else if (x == 2)
radioButton2.Text = answer;
else if (x == 3)
radioButton3.Text = answer;
else if (x == 4)
radioButton4.Text = answer;
}
}
}