Question

我有这个代码。代码从表，表内容，一些文本框和其他东西中获取了一些值。当我点击按钮提交按钮时，我得到一个值并输入“st”（类型类学生）并放入数据库。但它在列表属性“ get {....}”中向我显示异常“System.StackOverflowException”

     public StudentManager()
            : base(ConfigurationManager.ConnectionStrings["con"].ConnectionString)
    {

    }
        public override void Add(Student entity)
        {
           //add to database 
        }

        protected void submitButton_Click(object sender, EventArgs e)
        {
            Student st = new Student();
            st.id = Convert.ToInt32(IdTextBox.Text);
            st.AVG = Convert.ToDouble(AVGTextBox.Text);
            st.date = dateCalendar.TodaysDate;
            st.educationInfo = educationInfoTextBox.Text;
            faculty fa = new faculty();
            fa.id = Convert.ToInt32(facultyDropDownList.SelectedValue);
            st.faculty = fa;
            st.fatherName = fatherNameTextBox.Text;
            st.fName = fNameTextBox.Text;
            st.lName = lNameTextBox.Text;
            st.motherName = motherNameTextBox.Text;
            st.password = passwordTextBox.Text;
            st.personalInfo = personalInfoTextBox.Text;
            StudentManager sm = new StudentManager();
            sm.Add(st);
        }
 public class Student 
    {
        public int id { get; set; }

        public faculty faculty { get; set; }
        public double AVG { get; set; }
        public DateTime date { get; set; }
        public string educationInfo { get; set; }
        public string fatherName { get; set; }
        public string fName { get; set; }
        public string lName { get; set; }
        public string motherName { get; set; }
        public string password { get; set; }
        public string personalInfo { get; set; }
        private List<SqlParameter> Attributes;
        public List<SqlParameter> attributes
        {
            get
            {
                Attributes = new List<SqlParameter>();
                SqlParameter sp = new SqlParameter();
                attributes.Add(new SqlParameter("id",this.id));
                attributes.Add(new SqlParameter("faculty", this.faculty));
                attributes.Add(new SqlParameter("AVG", this.AVG));
                attributes.Add(new SqlParameter("date", date));
                attributes.Add(new SqlParameter("educationInfo",educationInfo));
                attributes.Add(new SqlParameter("fatherName", fatherName));
                attributes.Add(new SqlParameter("lName", lName));
                attributes.Add(new SqlParameter("motherName", motherName));
                attributes.Add(new SqlParameter("password", password));
                attributes.Add(new SqlParameter("personalInfo", personalInfo));
                return Attributes;
            }

        }

    }

Answer 1

您的attributes_Get方法以递归方式调用自身。

将其更改为：

    // this should be a Get() method, not a property.
    public List<SqlParameter> GetAttributes()
    {
        attributes = new List<SqlParameter>();
        SqlParameter sp = new SqlParameter();
        attributes.Add(new SqlParameter("id",this.id));
        attributes.Add(new SqlParameter("faculty", this.faculty));
        attributes.Add(new SqlParameter("AVG", this.AVG));
        attributes.Add(new SqlParameter("date", date));
        attributes.Add(new SqlParameter("educationInfo",educationInfo));
        attributes.Add(new SqlParameter("fatherName", fatherName));
        attributes.Add(new SqlParameter("lName", lName));
        attributes.Add(new SqlParameter("motherName", motherName));
        attributes.Add(new SqlParameter("password", password));
        attributes.Add(new SqlParameter("personalInfo", personalInfo));
        return attributes;
    }

Answer 2

这是因为你的类中的属性进行递归调用。

public List<SqlParameter> attributes
        {
            get
            {
                Attributes = new List<SqlParameter>();
                SqlParameter sp = new SqlParameter();
                attributes.Add(new SqlParameter("id",this.id));
                attributes.Add(new SqlParameter("faculty", this.faculty));
                attributes.Add(new SqlParameter("AVG", this.AVG));
                attributes.Add(new SqlParameter("date", date));
                attributes.Add(new SqlParameter("educationInfo",educationInfo));
                attributes.Add(new SqlParameter("fatherName", fatherName));
                attributes.Add(new SqlParameter("lName", lName));
                attributes.Add(new SqlParameter("motherName", motherName));
                attributes.Add(new SqlParameter("password", password));
                attributes.Add(new SqlParameter("personalInfo", personalInfo));
                return Attributes;
            }

要解决此问题，我觉得将其转换为方法而不是使用属性会更好。可以这样做：

public List<SqlParameter> GetAttributes()
{
    //replace your code here to get attributes
    List<SqlParameter> attributes = new List<SqlParameter>();
    SqlParameter sp = new SqlParameter();
    attributes.Add(new SqlParameter("id", this.id));
    attributes.Add(new SqlParameter("faculty", this.faculty));
    attributes.Add(new SqlParameter("AVG", this.AVG));
    attributes.Add(new SqlParameter("date", date));
    attributes.Add(new SqlParameter("educationInfo", educationInfo));
    attributes.Add(new SqlParameter("fatherName", fatherName));
    attributes.Add(new SqlParameter("lName", lName));
    attributes.Add(new SqlParameter("motherName", motherName));
    attributes.Add(new SqlParameter("password", password));
    attributes.Add(new SqlParameter("personalInfo", personalInfo));
    return attributes;
}

从代码中删除private List<SqlParameter> Attributes;

Answer 3

因为当您的代码调用此属性时：

    public List<SqlParameter> attributes
    {
        get
        {
            Attributes = new List<SqlParameter>();
            SqlParameter sp = new SqlParameter();
            attributes.Add(new SqlParameter("id",this.id));
            attributes.Add(new SqlParameter("faculty", this.faculty));
            attributes.Add(new SqlParameter("AVG", this.AVG));
            attributes.Add(new SqlParameter("date", date));
            attributes.Add(new SqlParameter("educationInfo",educationInfo));
            attributes.Add(new SqlParameter("fatherName", fatherName));
            attributes.Add(new SqlParameter("lName", lName));
            attributes.Add(new SqlParameter("motherName", motherName));
            attributes.Add(new SqlParameter("password", password));
            attributes.Add(new SqlParameter("personalInfo", personalInfo));
            return Attributes;
        }

    }

它到达attributes.Add()行再次调用此属性进行递归调用，因此使用另一个变量名称，即

    public List<SqlParameter> attributes
    {
        get
        {
            var myAttributes= new List<SqlParameter>();
            SqlParameter sp = new SqlParameter();
            myAttributes.Add(new SqlParameter("id",this.id));
            myAttributes.Add(new SqlParameter("faculty", this.faculty));
            myAttributes.Add(new SqlParameter("AVG", this.AVG));
            myAttributes.Add(new SqlParameter("date", date));
            myAttributes.Add(new SqlParameter("educationInfo",educationInfo));
            myAttributes.Add(new SqlParameter("fatherName", fatherName));
            myAttributes.Add(new SqlParameter("lName", lName));
            myAttributes.Add(new SqlParameter("motherName", motherName));
            myAttributes.Add(new SqlParameter("password", password));
            myAttributes.Add(new SqlParameter("personalInfo", personalInfo));
            return myAttributes;
        }

    }

为什么我得到异常“System.StackOverflowException”？

3 个答案: