Question

我想将对象列表保存到xml。我还使用gridView在列表中显示对象。我正在使用xml.serialization库。从xml保存是可以的，没有错误。在我加载文件后，对象出现在列表中，但我得到的错误索引是OutOfRange。我无法找到问题所在。

有错误：

System.ArgumentOutOfRangeException：索引超出范围。必须是非负数且小于集合的大小。
  参数名称：索引
  在System.Collections.ArrayList.get_Item（Int32索引）
  在System.Windows.Forms.DataGridViewSelectedRowCollection.get_Item（Int32 index）

我的主要声明：

private Teams team1, team2;
DataTable tQues = new DataTable(), tAnsw = new DataTable();
List<Question> ques = new List<Question>(); private bool edQues = false; 
private int quesSelected = -1;
List<Answers> answ = new List<Answers>(); private bool edAnsw = false; 
private int answSelected = -1;

班级Question：

public class Question
{
   public static int nextID = 1;
   public int questionID;
   public String text;
   public int maxPoints;
   public int answersCount = 0;
   public int pointsCount = 0;
   public bool played = false;

   public Question()
   {
        this.questionID = nextID++;
   }

   public Question(String text, int maxPoints) 
   {
        this.questionID = nextID++;
        this.text = text;
        this.maxPoints = maxPoints;
   }

   public static void Save(List<Question> list) 
   {
        using (var file = new FileStream("Questions.xml", FileMode.Create)) {
            XmlSerializer xml = new XmlSerializer(typeof(List<Question>));
            xml.Serialize(file, list);
        }
   }

   public static List<Question> Load() 
   {
        using (var file = new FileStream("Questions.xml", FileMode.Open))
        {
            XmlSerializer xml = new XmlSerializer(typeof(List<Question>));

            return (List<Question>) xml.Deserialize(file);
        }
   }
}

我从文件中加载了对象列表。

private void fMain_Load(object sender, EventArgs e)
{
        if (File.Exists("Questions.xml"))
        {
            ques = Question.Load();
        }

        //add columns to ques
        tQues.Columns.Add("id", typeof(int));
        tQues.Columns.Add("intrebarea", typeof(String));
        tQues.Columns.Add("maxPoints", typeof(int));
        tQues.Columns.Add("played", typeof(String));

        // add columns to answ
        tAnsw.Columns.Add("id", typeof(int));
        tAnsw.Columns.Add("questionid", typeof(int));
        tAnsw.Columns.Add("teamid", typeof(int));
        tAnsw.Columns.Add("text", typeof(String));
        tAnsw.Columns.Add("points", typeof(int));

        //open queries
        OpenQues();
        OpenAnsw();
}

我将对象加载到网格：

private void OpenQues()
{
        tQues.Clear();

        foreach (Question i in ques)
        {
            tQues.Rows.Add(i.questionID, i.text, i.maxPoints, i.played ? "yes" : "no");
        }

        gridQuestions.DataSource = tQues;
        gridQuestions.Columns[0].Visible = false;
}

我有错误（第70行）：

private void setQuesSelected()
{
        if (gridQuestions.Rows.Count > 0)
            foreach (Question i in ques)
            {
         /*70 line*/if (Convert.ToInt32(gridQuestions.Rows[gridQuestions.SelectedRows[0].Index].Cells[0].Value) == i.questionID)
                {
                    quesSelected = ques.IndexOf(i);
                    break;
                }
            }
        else
            quesSelected = -1;
}

Answer 1

在你的情况下，gridQuestions.SelectedRows[0].Index等于-1或SelectedRows为空，因为你没有选择行

xml序列化后读取xml的问题

1 个答案: