这是我的一个例子……它不会真正帮助你,因为我想让我的视图模型做的将不同于你想让你的视图模型做的……但也许它会给你一个开始。而基类的问题是,如果你把它放在你的核心中……你只需要写一次……
Imports System.ComponentModel
Imports System.Windows
Imports Microsoft.Practices.Composite.Events
Imports WavelengthIS.Core.Services
Imports WavelengthIS.Core.Bases
Imports Ocean.OceanFramework.CommonDialog
Imports WavelengthIS.WPF.Events
Namespace WavelengthIS.WPF.Bases
Public MustInherit Class ViewModelBase
Inherits WavelengthIS.Core.Bases.Base
Implements IDisposable, INotifyPropertyChanged
#Region " Declarations "
Private _headerinfo As String
Private _backgroundworker As BackgroundWorker
#End Region
#Region " Properties "
Public Property HeaderInfo() As String
Get
Return _headerinfo
End Get
Set(ByVal value As String)
If Not (value Is String.Empty) Or Not (IsNothing(value)) Then
_headerinfo = value
End If
End Set
End Property
Protected ReadOnly Property BackGroundWorker() As BackgroundWorker
Get
If _backgroundworker Is Nothing Then
_backgroundworker = New BackgroundWorker
End If
Return _backgroundworker
End Get
End Property
Private _isdirty As Boolean = False
Protected Property IsDirty As Boolean
Get
Return _isdirty
End Get
Set(ByVal value As Boolean)
If Not Equals(value, _isdirty) Then
_isdirty = value
If _isdirty = True Then
DisableNavigation()
Else
EnableNavigation()
End If
End If
End Set
End Property
''' <summary>
''' not a databinding property. No need for onpropertychanged notifications
''' </summary>
''' <value></value>
''' <returns></returns>
''' <remarks></remarks>
Protected Property IsLoading As Boolean = False
Private _haschanges As Boolean
Public Property HasChanges As Boolean
Get
Return _haschanges
End Get
Set(ByVal value As Boolean)
If Not Equals(value, _haschanges) Then
_haschanges = value
If value = True Then
GetEvent(Of Events.DisableCloseButtonEvent).Publish(True)
End If
OnPropertyChanged("HasChanges")
End If
End Set
End Property
#End Region
#Region " Dialogs "
'This is not in Bases because it would cause circular references.
''' <summary>
''' Gets the IDialogService registered with the ServiceContainer.
''' use ShowMessage or ShowException in child code.
''' </summary>
Private ReadOnly Property Dialog() As Dialog.IDialogService
Get
Return GetService(Of Dialog.IDialogService)()
End Get
End Property
Protected Function ShowMessage(ByVal message As String, ByVal caption As String, ByVal button As Dialog.DialogButton, ByVal image As Dialog.DialogImage) As Ocean.OceanFramework.CommonDialog.CustomDialogResult
GetEvent(Of Events.DialogShowingEvent).Publish(True)
Dim rslt As CustomDialogResult = Dialog.ShowMessage(message, caption, button, image)
GetEvent(Of Events.DialogShowingEvent).Publish(False)
Return rslt
End Function
Protected Sub ShowException(ByVal message As String, Optional ByVal expandedMessage As String = Nothing, Optional ByVal image As Dialog.DialogImage = Core.Services.Dialog.DialogImage.Error)
GetEvent(Of Events.DialogShowingEvent).Publish(True)
Dialog.ShowException(message, expandedMessage, image)
GetEvent(Of Events.DialogShowingEvent).Publish(False)
End Sub
#End Region
#Region " Wait States "
Private ReadOnly Property Wait As WavelengthIS.Core.Services.IWaitingService
Get
Return GetService(Of IWaitingService)()
End Get
End Property
Protected Sub BeginWait()
GetEvent(Of Events.DisplayWaitingControlEvent).Publish(True)
End Sub
Protected Sub EndWait()
GetEvent(Of Events.DisplayWaitingControlEvent).Publish(False)
End Sub
#End Region
#Region " Events "
Public Event PropertyChanged(ByVal sender As Object, ByVal e As System.ComponentModel.PropertyChangedEventArgs) Implements System.ComponentModel.INotifyPropertyChanged.PropertyChanged
#End Region
#Region " Constructor "
Public Sub New()
_backgroundworker = New BackgroundWorker
AddHandler _backgroundworker.DoWork, AddressOf BackGroundWorker_DoWork
AddHandler _backgroundworker.RunWorkerCompleted, AddressOf BackGroundWorker_RunWorkerCompleted
End Sub
#End Region
#Region " IDisposable Support "
Private disposedValue As Boolean = False ' To detect redundant calls
' IDisposable
Protected Overridable Sub Dispose(ByVal disposing As Boolean)
If Not Me.disposedValue Then
If disposing Then
' TODO: free other state (managed objects).
End If
' TODO: free your own state (unmanaged objects).
' TODO: set large fields to null.
End If
Me.disposedValue = True
End Sub
' This code added by Visual Basic to correctly implement the disposable pattern.
Public Sub Dispose() Implements IDisposable.Dispose
' Do not change this code. Put cleanup code in Dispose(ByVal disposing As Boolean) above.
Dispose(True)
GC.SuppressFinalize(Me)
End Sub
#End Region
#Region " Debugging Helpers "
<Conditional("DEBUG")> _
Public Sub VerifyPropertyName(ByVal propertyName As String)
'If you raise PropertyChanged and do not specify a property name,
'all properties on the object are considered to be changed by the binding system.
If String.IsNullOrEmpty(propertyName) Then
Return
End If
' Verify that the property name matches a real,
' public, instance property on this object.
'If TypeDescriptor.GetProperties(Me)(propertyName) Is Nothing Then
' Dim msg As String = "Invalid property name: " & propertyName
' Throw New Exception(msg)
'End If
End Sub
Private _ThrowOnInvalidPropertyName As Boolean
Protected Property ThrowOnInvalidPropertyName() As Boolean
Get
Return _ThrowOnInvalidPropertyName
End Get
Private Set(ByVal value As Boolean)
_ThrowOnInvalidPropertyName = value
End Set
End Property
#End Region
#Region " INotifyProperty Changed Method "
Protected Overridable Sub OnPropertyChanged(ByVal strPropertyName As String)
Me.VerifyPropertyName(strPropertyName)
If Me.PropertyChangedEvent IsNot Nothing Then
RaiseEvent PropertyChanged(Me, New System.ComponentModel.PropertyChangedEventArgs(strPropertyName))
End If
End Sub
Private Function QualifyString(ByVal str As String) As Boolean
Return True
End Function
Protected Overridable Sub OnPropertyChanged(ByVal strPropertyName As String, ByVal IsPrimaryProperty As Boolean)
Me.OnPropertyChanged(strPropertyName)
End Sub
#End Region
#Region " Navigation Events "
Protected Sub EnableNavigation()
'Keep from firing multiple onPropertyChanged events
If HasChanges = True Then
HasChanges = False
End If
GetEvent(Of DisableNavigationEvent).Publish(False)
End Sub
Protected Sub DisableNavigation()
'Keep from firing multiple onPropertyChanged events
If HasChanges = False Then
HasChanges = True
End If
GetEvent(Of DisableNavigationEvent).Publish(True)
End Sub
#End Region
End Class
End Namespace
