正在从数据库更新信息-错误数据库已锁定

Question

我创建了一个类似测验的应用程序..当我尝试在标签中显示分数时，我得到了这个错误：

An unhandled exception of type 'System.Data.SQLite.SQLiteException' occurred in System.Data.SQLite.dll   Additional information: database is locked database is locked

我知道哪一个是问题所在，但我不知道如何解决它。这个问题肯定存在于菜单表单(“最高父级”)。我知道这是因为应用程序从测验表单更新数据库，但当它返回并读取数据库以便我可以更改标签时，我收到了这个错误。

update_score() -reads数据库和更改标签

结论:我不能在标签中显示最高分两次:当我打开应用程序时，当我从测验form..So返回时，我必须在显示对话框之后(用户返回时不会知道分数)或在Meniu /Meniu_Load (它在开始时不显示)中对update_score进行注释。我该怎么解决它呢？

菜单代码：

public partial class Meniu : Form
{
    SQLiteConnection con;
    public bool con_opened = false; // tin minte daca am deschis conexiunea
    public int bs_lit=0, bs_info = 0;

    public Meniu()
    {            
        //this.StartPosition = FormStartPosition.CenterScreen;            
        InitializeComponent();
        con_opened=false;
        update_score();   
    }
    private void Meniu_Load(object sender, EventArgs e)
    {
        //con_opened=false;
        //update_score();

    } 

    public void db1_read()
    {
        if (con_opened == false)
        {
            con = new SQLiteConnection("Data Source=MyDatabase.sqlite;Version=3;");//Version=3;
            con_opened = true;
            con.Open();
        }

        string sql = "select * from bestscore WHERE materie LIKE 'literatura'";
        SQLiteCommand command = new SQLiteCommand(sql, con);
        SQLiteDataReader reader = command.ExecuteReader();
        reader.Read();
        bs_lit = Int32.Parse(reader[1].ToString());
        command.Dispose();


        sql = "select * from bestscore WHERE materie LIKE 'informatica'";
        SQLiteCommand cmd = new SQLiteCommand(sql, con);
        SQLiteDataReader rdr = cmd.ExecuteReader();
        rdr.Read();
        bs_info = Int32.Parse(rdr[1].ToString());
        cmd.Dispose();

        con.Close();
        con_opened = false;
    }       

    private void update_score()
    {
        db1_read();           
        lbl_bs_info.Text = bs_info.ToString();
        lbl_bs_lit.Text = bs_lit.ToString();            
    }





    private void btn_literatura_testare_Click(object sender, EventArgs e)
    {
        testare flit = new testare();
        this.Hide();
        flit.reveal = false;
        flit.materie = "literatura";
        flit.ShowDialog();
        update_score(); // if the function is here and in Meniu()
        // or Meniu_load()I receive the error
           // if it`s just one of them
                 //it works just fine

        if (flit.reveal == true)
            this.Show();
        else
            Application.Exit();
    }      
}

谢谢!

Answer 1

我找到了答案:我没有处置读者。现在它起作用了。

public void db1_read()
    {
        if (con_opened == false)
        {
            con = new SQLiteConnection("Data Source=MyDatabase.sqlite;Version=3;");//Version=3;
            con_opened = true;
            con.Open();
        }

        string sql = "select * from bestscore WHERE materie LIKE 'literatura'";
        SQLiteCommand command = new SQLiteCommand(sql, con);
        SQLiteDataReader reader = command.ExecuteReader();
        reader.Read();
        bs_lit = Int32.Parse(reader[1].ToString());
        command.Dispose();
        reader.Dispose();


        sql = "select * from bestscore WHERE materie LIKE 'informatica'";
        SQLiteCommand cmd = new SQLiteCommand(sql, con);
        SQLiteDataReader rdr = cmd.ExecuteReader();
        rdr.Read();
        bs_info = Int32.Parse(rdr[1].ToString());
        cmd.Dispose();
        rdr.Dispose();

        con.Close();
        con_opened = false;
    }