如何从 WPF 应用程序连接到 SQLite

Question

我尝试了这个解决方案，但没有成功。应用程序启动，但一段时间后失败。我不知道该怎么办，你能帮助我吗？我使用 Microsoft.Sqlite.Data 包来解决这个问题，但我不知道如何使用。由于某种原因我无法解决这个问题，但我需要这个来参加学校考试。它告诉我文件名不存在，但它存在。

namespace WpfApp2
{
    /// <summary>
    /// Interaction logic for MainWindow.xaml
    /// </summary>
    public partial class MainWindow : Window
    {
        SqliteConnection connection;
        ObservableCollection<Orszag> dataList = new();
        public MainWindow()
        {
            InitializeComponent();
        }

        private void letrehozButton_Click(object sender, RoutedEventArgs e)
        {
            connection = new($"Filename=adatok.db");
            connection.Open();
            string createTableText = "CREATE TABLE IF NOT EXISTS orszagok(id INTEGER PRIMARY KEY AUTOINCREMENT, nev VARCHAR(100), terulet INTEGER, nepesseg INTERGER, fovaros VARCHAR(100), fovarosNepesseg INTERGER)";
            SqliteCommand command = new(createTableText, connection);
            command.ExecuteNonQuery();
            foreach (var item in File.ReadAllLines("adatok-utf8.txt", Encoding.UTF8).Skip(1))
            {
                string[] parts = item.Split(';');
                string orszag = parts[0];
                int terulet = Convert.ToInt32(parts[1]);
                long nepesseg;
                if (parts[2].EndsWith('g'))
                {
                    parts[2] = parts[2].Trim('g');
                    nepesseg = Convert.ToInt64(parts[2]) * 10000;
                }
                else
                {
                    nepesseg = Convert.ToInt64(parts[2]);
                }
                string fovaros = parts[3];
                int fovarosnepesseg = Convert.ToInt32(parts[4]);
                string insertintotext = $"INSERT INTO orszagok(nev, terulet, nepesseg, fovaros, fovarosNepesseg) VALUES('{orszag}', '{terulet}', '{nepesseg}', '{fovaros}', '{fovarosnepesseg}')";
                command = new(insertintotext, connection);
                command.ExecuteNonQuery();
            }
            connection.Close();
        }

        private void readToTable_Click(object sender, RoutedEventArgs e)
        {
            connection = new($"Filename=adatok.db");
            connection.Open();
            string queryText = "SELECT * FROM orszagok";
            SqliteCommand command = new(queryText, connection);
            SqliteDataReader reader = command.ExecuteReader();
            dataList = new();
            while (reader.Read())
            {
                int id = reader.GetInt32(0);
                string nev = reader.GetString(1);
                int terulet = reader.GetInt32(2);
                long nepesseg = reader.GetInt64(3);
                string fovaros = reader.GetString(4);
                int fovarosNepesseg = reader.GetInt32(5);
                Orszag newElement = new(id, nev, terulet, nepesseg, fovaros, fovarosNepesseg);
                dataList.Add(newElement);
            }
            resultTable.ItemsSource = dataList;
            reader.Close();
        }

        private void deleteButton_Click(object sender, RoutedEventArgs e)
        {
            Orszag selected = resultTable.SelectedItem as Orszag;
            string deleteText = $"DELETE FROM orszagok WHERE id={selected.Id}";
            SqliteCommand command = new(deleteText, connection);
            command.ExecuteNonQuery();
            dataList.Remove(selected);
        }
    }
}

Answer 1

使用绝对路径：您可以指定文件的绝对路径，而不是依赖当前工作目录中的文件。这确保应用程序确切地知道在哪里可以找到它。

string filePath = @"C:\Path\To\Your\File\adatok-utf8.txt";
foreach (var item in File.ReadAllLines(filePath, Encoding.UTF8).Skip(1))