有没有办法在 Xamarin 中轻松地将网格绑定到表格，就像在我的 WinForms 代码中一样？

Question

i am new to xamarin, i need to easily link a grid (or something similar) to my MySql database table. In WinForms I had done it by putting a grid with the designer and with a few lines of code, but instead with Xamarin I can't do anything ... My current project is a XamarinForm with the default "tab" preset.

Here is the WinForm code:

        try
        {
            MySqlConnection cnn;
            string connetionString = "server=sql7.freesqldatabase.com;database=------;port=----;uid=-------;pwd=------;";
            cnn = new MySqlConnection(connetionString);

            DataTable dt = new DataTable();

            MySqlCommand cmd;
            cnn.Open();

            cmd = cnn.CreateCommand();
            cmd.CommandText = "SELECT * from Products";
            MySqlDataAdapter adapter = new MySqlDataAdapter(cmd);
            adapter.Fill(dt);
            dataGridView1.DataSource = dt; //dataGridView WinFrom component

            cnn.Close();
        }
        catch (Exception ex)
        {
            MessageBox.Show(ex.Message);
        }

Is there a way to do this in Xamarin? (my goal is to display all the db table in one page)

Answer 1

Welcome to SO!

Although there is not the same way that Xamarin can use DataTable as Source directly, but there is an another way to convert Table Date and make it used for Control(Such as CollectionView , DataGrid , etc).

For example, ItemSource can be set as follows:

MyDataGrid.ItemsSource = await TodoItemDatabase.Database.Table<TodoItem>().ToListAsync();

Here the TodoItem is the Model of table data, you need to create it in Xamarin Forms manually. Then the app will convert the table data to list data according to the model style.

using SQLite;
public class TodoItem
{
    [PrimaryKey, AutoIncrement]
    public int ID { get; set; }
    public string Name { get; set; }
    public string Notes { get; set; }
    public bool Done { get; set; }
}

About using Databases in Xamarin, you can refer to this official document .And there is a sample project for reference. Above code TodoItemDatabase class also based on this sample.

Here is the TodoItemDatabase class:

public class TodoItemDatabase
{
    static readonly Lazy<SQLiteAsyncConnection> lazyInitializer = new Lazy<SQLiteAsyncConnection>(() =>
    {
        return new SQLiteAsyncConnection(Constants.DatabasePath, Constants.Flags);
    });

    public static SQLiteAsyncConnection Database => lazyInitializer.Value;
    static bool initialized = false;

    public TodoItemDatabase()
    {
        InitializeAsync().SafeFireAndForget(false);
    }

    async Task InitializeAsync()
    {
        if (!initialized)
        {
            if (!Database.TableMappings.Any(m => m.MappedType.Name == typeof(TodoItem).Name))
            {
                await Database.CreateTablesAsync(CreateFlags.None, typeof(TodoItem)).ConfigureAwait(false);                    
            }
            initialized = true;
        }
    }

    public Task<List<TodoItem>> GetItemsAsync()
    {
        return Database.Table<TodoItem>().ToListAsync();
    }

    public Task<List<TodoItem>> GetItemsNotDoneAsync()
    {
        return Database.QueryAsync<TodoItem>("SELECT * FROM [TodoItem] WHERE [Done] = 0");
    }

    public Task<TodoItem> GetItemAsync(int id)
    {
        return Database.Table<TodoItem>().Where(i => i.ID == id).FirstOrDefaultAsync();
    }

    public Task<int> SaveItemAsync(TodoItem item)
    {
        if (item.ID != 0)
        {
            return Database.UpdateAsync(item);
        }
        else
        {
            return Database.InsertAsync(item);
        }
    }

    public Task<int> DeleteItemAsync(TodoItem item)
    {
        return Database.DeleteAsync(item);
    }
}

And Constants class which contains database name and other things.

public static class Constants
{
    public const string DatabaseFilename = "TodoSQLite.db3";

    public const SQLite.SQLiteOpenFlags Flags =
        // open the database in read/write mode
        SQLite.SQLiteOpenFlags.ReadWrite |
        // create the database if it doesn't exist
        SQLite.SQLiteOpenFlags.Create |
        // enable multi-threaded database access
        SQLite.SQLiteOpenFlags.SharedCache;

    public static string DatabasePath
    {
        get
        {
            var basePath = Environment.GetFolderPath(Environment.SpecialFolder.LocalApplicationData);
            return Path.Combine(basePath, DatabaseFilename);
        }
    }
}