Question

我怎样才能做到这一点，每当我向数据库添加/更新/删除数据时，UI都会更新（在wpf中）。我正在使用实体框架+本地sql。我有entityframework生成的以下类：当我添加一个事务时：我需要/可以指定一个Payee和一个TransactionCategory对象。公共部分类交易 { public int TransactionId {get;组; }

    [Column(TypeName = "money")]
    public decimal TransactionAmmount { get; set; }

    public int? TransactionCategoryId { get; set; }

    public int? PayeeId { get; set; }

    [Column(TypeName = "money")]
    public decimal? TotalAmmount { get; set; }

    public int? TransactionType { get; set; }

    [Column(TypeName = "date")]
    public DateTime? TransactionDate { get; set; }


    public virtual Payee Payee { get; set; }

    public virtual TransactionCategory TransactionCategory { get; set; }
}


public partial class Payee
{
    public Payee()
    {
        Bills = new HashSet<Bill>();
        Transactions = new HashSet<Transaction>();
    }

    public int PayeeId { get; set; }

    [Required]
    [StringLength(50)]
    public string PayeeName { get; set; }

    public bool HasAccounts { get; set; }

    [StringLength(50)]
    public string PayeePhone { get; set; }

    [StringLength(50)]
    public string PayeeAddress { get; set; }

    public virtual ICollection<Bill> Bills { get; set; }

    public virtual ICollection<Transaction> Transactions { get; set; }
}

public partial class TransactionCategory
{
    public TransactionCategory()
    {
        Bills = new HashSet<Bill>();
        Transactions = new HashSet<Transaction>();
    }

    [Key]
    public int CategoryId { get; set; }

    [Required]
    [StringLength(50)]
    public string CategoryName { get; set; }

    [Column(TypeName = "money")]
    public decimal CategoryExpenseLimit { get; set; }

    [Column(TypeName = "money")]
    public decimal CategoryExpense { get; set; }

    [Column(TypeName = "money")]
    public decimal CategoryIncome { get; set; }

    [StringLength(50)]
    public string Period { get; set; }

    public virtual ICollection<Bill> Bills { get; set; }

    public virtual ICollection<Transaction> Transactions { get; set; }
}

在他们的viewmodels中我使用的方法来添加数据：

PayeeViewModel类：以及要添加的方法。

 private void Update()
    {
        using (var context = new Ents())
        {
            if (this.Mode == Mode.Add)
            {
                if (string.IsNullOrEmpty(PayeeName))
                {
                    MessageBox.Show("A Payee Name must be entered");
                }
                else
                {      
                    PayeeModel payee = new PayeeModel() { ThePayee = { PayeeName = PayeeName, PayeeAddress = PayeeAddress, PayeePhone = PayeePhone, HasAccounts = PayeeHasAccount } };

                        context.Payees.Add(payee.ThePayee);
                        context.SaveChanges();

                }
            }
       }
   }

除了字段外，TransactionCategoryViewModel更新方法相同。

在我的TransactionViewModel中：

我有一个Payees和一个类别列表：

Payees列表：

 private ObservableCollection<PayeeModel> payees;
        private PayeeModel selectedPayee;

        public ObservableCollection<PayeeModel> Payees
        {
            get { return payees; }
            set
            {
                payees = value;
                OnPropertyChanged("Payees");
            }
        }

        public PayeeModel SelectedPayee
        {
            get { return selectedPayee; }
            set { selectedPayee = value;
            OnPropertyChanged("SelectedPayee");
            }
        }

类别列表

private ObservableCollection<CategoryModelModel> categories;
        private CategoryModel selectedCategory;

        public ObservableCollection<CategoryModel> Categories
        {
            get { return payees; }
            set
            {
                payees = value;
                OnPropertyChanged("Categories");
            }
        }

        public CategoryModel SelectedCategory
        {
            get { return selectedCategory; }
            set { selectedCategory = value;
            OnPropertyChanged("SelectedCategory");
            }
        }

和TransactionViewModel的构造函数

  internal TransactionViewModel(TransactionModel transaction, IEventAggregator eventAggregator)
    {
        this.eventAggregator = eventAggregator;
        TransactionId = transaction.TheTransaction.TransactionId;
        ammount = (double)transaction.TheTransaction.TransactionAmmount;
        PayeeId = transaction.TheTransaction.PayeeId;

         GetCategories();
         GetPayees();
         SelectedPayee = payees.Where(i => i.ThePayee.PayeeId == PayeeId).First();
         SelectedCatgory = categories.Where(i => i.TheCategory.CategoryId == CategoryId).First();


    }

当我向数据库添加收款人或交易类别时，我希望它反映在包含收款人或交易类别的所有视图中。例如在TransactionView中（用于添加/编辑事务）我有TransactionClass中提到的字段和两个组合框：一个绑定到Payees列表，一个绑定到CategoriesList。

问题是，如果我添加/删除或更新Payee / TransactionCategory，则TransactionView中的组合框不会相应更新。

TransactionView组合框：

   <Label Content="Payee" Grid.Row="2" Margin="3" />
        <ComboBox Grid.Column="1" Grid.Row="2" Margin="3" Width="100" ItemsSource="{Binding Payees}" SelectedItem="{Binding SelectedPayee}"
                  DisplayMemberPath="ThePayee.PayeeName"/>
        <Label Content="Category" Grid.Row="3" Margin="3" />
        <ComboBox Grid.Column="1" Grid.Row="3" Margin="3" Width="100" ItemsSource="{Binding Categories}" 
                  SelectedItem="{Binding SelectedCategory}"  DisplayMemberPath="TheCategory.CategoryName" />

Answer 1

回答所以它不会保持开放。我在启动时创建了一个ObservableCollection，我将其作为资源添加，然后在需要它们的地方声明了本地实例。

Wpf，如何在将数据添加到数据库

1 个答案: