// 數(shù)據(jù)加載策略枚舉
public enum LoadStrategy 
{    
    Lazy,   // 延遲加載
    Batch,  // 分批加載
    Virtual // 虛擬模式
}

public interface IDataSource<T>
{
    List<T> GetData(int startIndex, int count);
    int GetTotalCount();
}

public class LargeDataEntity
{
    public long Id { get; set; }
    public string Name { get; set; }
    public DateTime CreatedTime { get; set; }
    public decimal Amount { get; set; }
    public string Description { get; set; }
}

public class VirtualDataSource : IDataSource<LargeDataEntity>
{
    public List<LargeDataEntity> GetData(int startIndex, int count)
    {
        var result = new List<LargeDataEntity>();
        for (int i = startIndex; i < startIndex + count; i++)
        {
            result.Add(new LargeDataEntity
            {
                Id = i,
                Name = $"數(shù)據(jù){i}",
                CreatedTime = DateTime.Now.AddMinutes(-i),
                Amount = i * 100,
                Description = $"大數(shù)據(jù)測試記錄{i}"
            });
        }
        return result;
    }

    public int GetTotalCount()
    {
        return 1_000_000; // 模擬百萬條數(shù)據(jù)
    }
}

private Dictionary<int, List<LargeDataEntity>> dataCache = new Dictionary<int, List<LargeDataEntity>>();
private const int CacheSize = 1000;

private void DataGridView_CellValueNeeded(object sender, DataGridViewCellValueEventArgs e)
{
    int blockIndex = e.RowIndex / CacheSize;
    if (!dataCache.TryGetValue(blockIndex, out var blockData))
    {
        blockData = dataSource.GetData(blockIndex * CacheSize, CacheSize);
        dataCache[blockIndex] = blockData;
        
        // 緩存管理：最多保留10個塊
        if (dataCache.Count > 10)
        {
            var oldestBlock = dataCache.Keys.Min();
            dataCache.Remove(oldestBlock);
        }
    }

    var rowInBlock = e.RowIndex % CacheSize;
    if (rowInBlock < blockData.Count)
    {
        var currentRow = blockData[rowInBlock];
        switch (e.ColumnIndex)
        {
            case 0: e.Value = currentRow.Id; break;
            case 1: e.Value = currentRow.Name; break;
            case 2: e.Value = currentRow.CreatedTime; break;
            case 3: e.Value = currentRow.Amount; break;
            case 4: e.Value = currentRow.Description; break;
            default: e.Value = string.Empty; break;
        }
    }
    else
    {
        e.Value = string.Empty;
    }
}

public async Task LoadDataAsync(int startIndex, int count, CancellationToken cancellationToken)
{
    try
    {
        UpdateLoadingStatus(true);
        var data = await Task.Run(() => dataSource.GetData(startIndex, count), cancellationToken);
        UpdateGridView(data);
    }
    catch (OperationCanceledException)
    {
        MessageBox.Show("數(shù)據(jù)加載已取消");
    }
    catch (Exception ex)
    {
        MessageBox.Show($"加載錯誤：{ex.Message}");
    }
    finally
    {
        UpdateLoadingStatus(false);
    }
}

public partial class Form1 : Form
{
    public Form1()
    {
        InitializeComponent();
        var dataSource = new VirtualDataSource();
        ConfigureDataGridView(dataSource);
    }

    private void ConfigureDataGridView(VirtualDataSource dataSource)
    {
        dataGridView1.Columns.Add("Id", "ID");
        dataGridView1.Columns.Add("Name", "名稱");
        dataGridView1.Columns.Add("CreatedTime", "創(chuàng)建時間");
        dataGridView1.Columns.Add("Amount", "金額");
        dataGridView1.Columns.Add("Description", "描述");

        var performanceLoader = new HighPerformanceDataLoader(dataGridView1, dataSource);
    }
}