使用 sqlite 在 xamarin 中连接表

Question

我正在使用 xamarin 和 sqlite 制作一个 android 应用程序。我正在尝试在按钮add 上连接数据库testdb.sqlite 的表user，但在我的平板电脑上调试应用程序时出现此错误：

SQLite.SQLiteException：无法打开数据库文件：/storage/emulated/0/testdb.sqlite/testdb.sqlite (CannotOpen)

我的代码是：

button_add.Click += delegate
{
    ring dbName = "testdb.sqlite";

    ///  Environment.GetFolderPath(Environment.SpecialFolder.ApplicationData);
    string dbPath = Path.Combine(Android.OS.Environment.ExternalStorageDirectory.ToString(), dbName);

    // Check if your DB has already been extracted.
    if (!File.Exists(dbPath))
    {
        using (BinaryReader br = new BinaryReader(Assets.Open(dbName)))
        {
            using (BinaryWriter bw = new BinaryWriter(new FileStream(dbPath, FileMode.Create)))
            {
                byte[] buffer = new byte[2048];
                int len = 0;
                while ((len = br.Read(buffer, 0, buffer.Length)) > 0)
                {
                    bw.Write(buffer, 0, len);
                }
            }
        }
    }

    editemail.Text = "I love coding"; 
    // db.createdatabase();

    //folder_loc.Text = folder;
    using (var connection = new SQLiteConnection(System.IO.Path.Combine(dbPath, dbName)))
    {
        //  connection.CreateTable<person>();

        //string query = "select * from test";
        // connection.Query <test> (query);


        var query = connection.Table<user>();

        foreach (var stock in query)
        {
            Console.WriteLine("Stock: " + stock.name);
            editname.Text = stock.name;
        }
    }
};

user 声明：

public class user
{
    public int id { get; set; }

    //public string email { get; set; }

    public string name { get; set; }

    //public string gender { get; set; }
}

Answer 1

好吧，您在代码中定义了两次名称，一次在这里：

string dbPath = Path.Combine(Android.OS.Environment.ExternalStorageDirectory.ToString(), dbName);

然后当你想打开它时，你使用 dbPath 和 dbName，要么删除 dbName 引用：

    string dbPath = Path.Combine(Android.OS.Environment.ExternalStorageDirectory.ToString(), dbName);

或在：

(var connection = new SQLiteConnection(System.IO.Path.Combine(dbPath, dbName)))

它应该可以工作；）