无法使用三层体系结构添加/更新

Question

我有一个名为Currency的表，其中有两个要插入的属性，即Unit和Rate。

当我按下add或edit，只有Unit被保存，但Rate保持0。

当我按delete时，记录被成功删除。

下面是数据层的代码

public interface ICurrencyRepository 
{ 
    List<Currency> GetAll(); 

    Currency GetById(int id); 

    Currency Insert(Currency obj); 

    void Update(Currency obj); 

    void Delete(Currency obj); 
} 

public class CurrencyRepository : ICurrencyRepository 
{ 
    public void Delete(Currency obj) 
    { 
     using (ApplicationDbContext db = new ApplicationDbContext()) 
     { 
      db.Currencies.Attach(obj); 
      db.Currencies.Remove(obj); 
      db.SaveChanges(); 
     } 
    } 

    public List<Currency> GetAll() 
    { 
     using (ApplicationDbContext db = new ApplicationDbContext()) 
     { 
      return db.Currencies.ToList(); 
     } 
    } 

    public Currency GetById(int id) 
    { 
     using (ApplicationDbContext db = new ApplicationDbContext()) 
     { 
      return db.Currencies.Find(id); 
     } 
    } 

    public Currency Insert(Currency obj) 
    { 
     using (ApplicationDbContext db = new ApplicationDbContext()) 
     { 
      db.Currencies.Add(obj); 
      db.SaveChanges(); 
      return obj; 
     } 
    } 

    public void Update(Currency obj) 
    { 
     using (ApplicationDbContext db = new ApplicationDbContext()) 
     { 
      db.Currencies.Attach(obj); 
      db.Entry(obj).State = System.Data.Entity.EntityState.Modified; 
      db.SaveChanges(); 
     } 
    } 
} 

下面是业务层的代码

public static class CurrencyServices 
{ 
    static ICurrencyRepository repository; 

    static CurrencyServices() 
    { 
     repository = new CurrencyRepository(); 
    } 

    public static List<Currency> GetAll() 
    { 
     return repository.GetAll(); 
    } 

    public static Currency GetById(int id) 
    { 
     return repository.GetById(id); 
    } 

    public static Currency Insert(Currency obj) 
    { 
     return repository.Insert(obj); 
    } 

    public static void Update(Currency obj) 
    { 
     repository.Update(obj); 
    } 

    public static void Delete(Currency obj) 
    { 
     repository.Delete(obj); 
    } 
} 

下面是我的UI（页与网格）的代码

private void btnNew_ItemClick(object sender, DevExpress.XtraBars.ItemClickEventArgs e) 
    { 
     DocumentController.ActivateForm(typeof(Test), null); 
     currencyBindingSource.DataSource = CurrencyServices.GetAll(); 
    } 

    private void btnEdit_ItemClick(object sender, DevExpress.XtraBars.ItemClickEventArgs e) 
    { 
     if (currencyBindingSource.Current == null) 
     { 
      return; 
     } 

     else 
     { 
      DocumentController.ActivateForm(typeof(Test), currencyBindingSource.Current as Currency); 
      currencyBindingSource.DataSource = CurrencyServices.GetAll(); 
     } 
    } 

下面是我的UI（编辑页）代码

bool isNew; 
    public CurrencyEdit(Currency obj) 
    { 
     InitializeComponent(); 
     if (obj == null) 
     { 
      currencyBindingSource.DataSource = new Currency(); 
      isNew = true; 
     } 

     else 
     { 
      currencyBindingSource.DataSource = obj; 
      isNew = false; 
     } 
    } 

    private void btnSave_ItemClick(object sender, DevExpress.XtraBars.ItemClickEventArgs e) 
    { 
     if (isNew) 
     { 
      CurrencyServices.Insert(currencyBindingSource.Current as Currency); 
     } 

     else 
     { 
      CurrencyServices.Update(currencyBindingSource.Current as Currency); 
     } 
    } 

下面是我currencyBindingSource如何得到创建，并在UI代码约束。

1. 从工具箱添加bindingSource。
2. 转至属性 - >数据源 - >添加项目数据源 - >对象 - >选择currency表。
3. 添加两个文本框 - >属性 - > DataBindings - > EditValue - >从currencyBindingSource中选择Unit和Rate。

Answer 1

这是你需要做的。我相信你缺少这些需要一些适当的强制转换：

private void btnSave_ItemClick(object sender, DevExpress.XtraBars.ItemClickEventArgs e) 
{ 
    EfTestDataSet.CurrencyRow currencyRow = (EfTestDataSet.CurrencyRow) (currencyBindingSource.Current as DataRowView).Row; 

    if (isNew) 
    { 
     CurrencyServices.Insert(new Currency { Unit = currencyRow.Unit, Rate = currencyRow.Rate }); 
    } 
    else 
    { 
     CurrencyServices.Update(new Currency { Unit = currencyRow.Unit, Rate = currencyRow.Rate }); 
    } 
} 

注：EfTestDataSet是得到了，而在我的应用程序添加绑定源创建数据源的数据集的名称。它可能在你的应用程序中有所不同。

希望这会有所帮助！