System.StackOverflowException 通过表单 [英] System.StackOverflowException by forms

问题描述

我正在尝试使用按钮打开另一个表单，但刚开始时还可以.在一些表格使 stackoverflow 错误之后！错误在表单 1、表单 2 和表单 3 上(我开始调试多次):代码非常简单.喜欢表格 3:

I'm trying to open another form with a button and it's only ok at the beginning. After a few forms made the stackoverflow error acours ! The error is on form 1, form 2 and form 3 (I started to debug multiple times): the codes are really simple. like for form 3:

public partial class Form2 : Form
{
    Form3 obrok = new Form3();
    public Form2()
    {
        InitializeComponent();
    }

    public void textBox1_TextChanged(object sender, EventArgs e)
    {
    }

    private void button1_Click(object sender, EventArgs e)
    {
        obrok.Show();
        this.Hide();
    }
}

(从注释中添加，特别是为了保留代码缩进(MI))

上述错误已解决(使用语句)现在问题是当我不想将值从文本框保存到访问数据库时.编码:表单 1 用户 = 新表单 1();private void button1_Click(object sender, EventArgs e){string conString = "Provider=Microsoft.Jet.OLEDB.4.0;"+ "数据源=C:\Users\Simon\Desktop\save.mdb";

The above error is solved(using statement) Now the problem is when i wan't to save values from textbox to the access database. The code: Form1 users=new Form1(); private void button1_Click(object sender, EventArgs e) { string conString = "Provider=Microsoft.Jet.OLEDB.4.0;" + "Data Source=C:\Users\Simon\Desktop\save.mdb";

        OleDbConnection empConnection = new OleDbConnection(conString);


        string insertStatement = "INSERT INTO obroki_save "
                             + "([ID_uporabnika],[datum],[ID_zivila],[skupaj_kalorij]) "
                             + "VALUES (@ID_uporabnika,@datum,@ID_zivila,@skupaj_kalorij)";

        OleDbCommand insertCommand = new OleDbCommand(insertStatement, empConnection);

        insertCommand.Parameters.Add("@ID_uporabnika", OleDbType.Char).Value = users.iDTextBox.Text;
        insertCommand.Parameters.Add("@datum", OleDbType.Char).Value = DateTime.Now;
        insertCommand.Parameters.Add("@ID_zivila", OleDbType.Char).Value = iDTextBox.Text;
        insertCommand.Parameters.Add("@skupaj_kalorij", OleDbType.Char).Value = textBox1.Text;
        empConnection.Open();

        try
        {
            int count = insertCommand.ExecuteNonQuery();
        }
        catch (OleDbException ex)
        {
            MessageBox.Show(ex.Message);
        }
        finally
        {
            empConnection.Close();
            textBox1.Clear();
            textBox2.Clear();
            textBox3.Clear();
            textBox4.Clear();
            textBox5.Clear();
        }
    }
}

当我不想传递值时，它会提示条件表达式中的数据类型有错误.

When i wan't to pass the values it show a massage that there is an error in the data type in conditional expression .

推荐答案

因此，Form2 在构造时实例化了一个新的 Form3，Form3 在构造时实例化了一个新的 Form5……也许 Form5 甚至实例化了另一个表单，然后又实例化了另一个表单等等?在我看来，您以某种方式声明了您的类，以便实例化其中一个实际上实例化了许多其他表单对象，甚至可能还有循环引用(例如 Form3=>Form5=>Form???=>...=>Form3=>Form5=>Form???=>... 永远)，因此您在表单的构造函数中陷入了无限递归.

So, Form2 instances a new Form3 when it's constructed, Form3 instances a new Form5 on construction... maybe Form5 even instances yet another form, which instances another one and so on? In my opinion, you declared your classes in a way so that instancing one of them actually instances a lot of other form objects, and maybe there's even a circular reference (e.g. Form3=>Form5=>Form???=>...=>Form3=>Form5=>Form???=>... forever), so you're stuck in infinite recursion in the constructors of your forms.

如果事情是这样的话，如果你的程序逻辑可能的话，你应该将你的表单声明移动到显示它们的方法中，最好是包含在 using 语句中:这样它们只有在需要时才会被实例化, 并在不再使用时完全销毁.

If things are like that, if possible for your program logic, you should move your declarations of the forms inside the method that shows them, better if enclosed inside a using statement: in this way they get instanced only when they are needed, and are destroyed exactly when they are no longer used.

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