我有一些连接在一起的 Linq to SQL 表类。我目前仅使用 LINQ to SQL 查询将其绑定到树视图。它可以工作,但它不显示何时从数据库中添加或删除内容。
我实现了 INotifyPropertyChanged 但它没有更新树视图。
我也尝试过使用 Bindable Linq,但似乎没有什么不同。
我找到了一个无需创建更多类即可轻松创建 ObservableCollections 的示例:jimlynn.wordpress.com/2008/12/09/using-observablecollection-with-linq/,(这很重要,因为我有未来项目迫在眉睫,需要与大量表(30 个左右)进行交互,并且仅创建 Linq to SQL 类将是一件痛苦的事情)。
Property ModelQuery As ObservableCollection(Of dbModels) = New ObservableCollection(Of dbModels)().PopulateFrom(From mm In tblModels.AsBindable Order By mm.ModelName)
这是一个好方法,还是我必须创建一个单独的 ObservableCollection 并在代码中维护它们。如果我要使用这种绑定的东西,我真的在寻找一种将东西链接在一起的方法,这样我就不必在进行更改时更新多个结构。
主表:
<Table(Name:="Models")> Public Class dbModels
Implements INotifyPropertyChanged
Private _changed As Boolean
Public Event PropertyChanged(ByVal sender As Object, ByVal e As PropertyChangedEventArgs) Implements INotifyPropertyChanged.PropertyChanged
Protected Overridable Sub OnPropertyChanged(ByVal Propertyname As String)
If Not Propertyname.Contains("Changed") Then
Changed = True
End If
RaiseEvent PropertyChanged(Me, New PropertyChangedEventArgs(Propertyname))
End Sub
Public Property Changed() As Boolean
Get
Return _changed
End Get
Set(ByVal value As Boolean)
If _changed <> value Then
_changed = value
OnPropertyChanged("Changed")
End If
End Set
End Property
Private _ModelID As Integer
<Column(Storage:="_ModelID", DbType:="int IDENTITY NOT NULL", IsPrimaryKey:=True, IsDbGenerated:=True, Name:="ModelID")> _
Public Property ModelID() As Integer
Get
Return Me._ModelID
End Get
Set(value As Integer)
Me._ModelID = value
End Set
End Property
Private _ModelName As String
<Column(Storage:="_ModelName", DbType:="Varchar(200)", Name:="ModelName")> _
Public Property ModelName() As String
Get
Return Me._ModelName
End Get
Set(value As String)
Me._ModelName = value
End Set
End Property
Private _ModelYears As EntitySet(Of dbModelYears) = New EntitySet(Of dbModelYears)
<Association(Storage:="_ModelYears", DeleteRule:="CASCADE", OtherKey:="ModelID")> _
Public Property ModelYears As EntitySet(Of dbModelYears)
Get
Return _ModelYears
End Get
Set(value As EntitySet(Of dbModelYears))
_ModelYears.Assign(value)
End Set
End Property
End Class
联表:
<Table(Name:="ModelYears")> Public Class dbModelYears
Implements INotifyPropertyChanged
Private _changed As Boolean
Public Event PropertyChanged(ByVal sender As Object, ByVal e As PropertyChangedEventArgs) Implements INotifyPropertyChanged.PropertyChanged
Protected Overridable Sub OnPropertyChanged(ByVal Propertyname As String)
If Not Propertyname.Contains("Changed") Then
Changed = True
End If
RaiseEvent PropertyChanged(Me, New PropertyChangedEventArgs(Propertyname))
End Sub
Public Property Changed() As Boolean
Get
Return _changed
End Get
Set(ByVal value As Boolean)
If _changed <> value Then
_changed = value
OnPropertyChanged("Changed")
End If
End Set
End Property
Private _ModelYearID As Integer
<Column(Storage:="_ModelYearID", DbType:="int IDENTITY NOT NULL", IsPrimaryKey:=True, IsDbGenerated:=True, Name:="ModelYearID")> _
Public Property ModelYearID() As Integer
Get
Return Me._ModelYearID
End Get
Set(value As Integer)
Me._ModelYearID = value
End Set
End Property
Private _ModelID As Integer
<Column(Storage:="_ModelID", DbType:="int", Name:="ModelID")> _
Public Property ModelID() As Integer
Get
Return Me._ModelID
End Get
Set(value As Integer)
Me._ModelID = value
End Set
End Property
Private _ModelYear As String
<Column(Storage:="_ModelYear", DbType:="Varchar(50)", Name:="ModelYear")> _
Public Property ModelYear() As String
Get
Return Me._ModelYear
End Get
Set(value As String)
Me._ModelYear = value
End Set
End Property
End Class