UWP迁移至.NET Framework4.8.1后Dispatcher构建失败的解决方案咨询

问题概述 #

原Visual Basic UWP项目（基于VS2022 17.6.3，使用Windows.UI.Core.CoreDispatcher处理跨线程UI更新）构建运行正常。转换为.NET Framework 4.8.1项目后，除Dispatcher相关代码外，其余部分映射正常，但因CoreDispatcher的引用版本冲突导致构建失败：

• UWP中CoreDispatcher来自Windows.Foundation.UniversalApiContract, Version=14.0.0.0
• .NET Framework项目中自动引用的CoreDispatcher来自Windows, Version=255.255.255.255，手动添加旧合约引用会引发大量额外错误。

UWP项目核心代码片段 #

MainPage类 #

Imports Windows.Devices.Enumeration
Imports Windows.Devices.Bluetooth.GenericAttributeProfile
Imports System.Text
Imports Windows.Storage.Streams
Imports System.Threading

Public NotInheritable Class MainPage
    Dim BleDevices As New ObservableCollection(Of DeviceInformation)()
    Dim BleServices As New ObservableCollection(Of GattDeviceService)()
    Dim BleCharacteristic As New ObservableCollection(Of GattCharacteristic)()

    WithEvents GetBleDev As New GetBleDevice(Dispatcher)
End Class

GetBleDevice类 #

Imports Windows.Devices.Bluetooth
Imports Windows.Devices.Enumeration
Imports Windows.UI.Core

Public Class GetBleDevice
    Private ReadOnly KnownDevices As New ObservableCollection(Of DeviceInformation)()
    Private deviceWatcher As DeviceWatcher

    Public Event GetBleDevices(DevicesBle As ObservableCollection(Of DeviceInformation))

    Private ReadOnly dispatcher As CoreDispatcher

    Public Sub New(iDispatcher As CoreDispatcher)
        dispatcher = iDispatcher
    End Sub
End Class

.NET Framework 4.8.1项目问题代码片段 #

'Imports System.Collections.ObjectModel
'Imports Windows.Storage.Streams
'Imports System.Threading
Imports Windows.Devices.Enumeration
Imports Windows.Devices.Bluetooth.GenericAttributeProfile
Imports System.ServiceModel

Public Class Form1
    Dim BleDevices As New ObservableCollection(Of DeviceInformation)()
    Dim BleServices As New ObservableCollection(Of GattDeviceService)()
    Dim BleCharacteristic As New ObservableCollection(Of GattCharacteristic)()

    WithEvents GetBleDev As New GetBleDevice(Dispatcher)
End Class

解决办法 #

1. 替换Dispatcher实现（核心修复） #

.NET Framework WinForms/WPF项目不兼容UWP的Windows.UI.Core.CoreDispatcher，需改用对应UI框架的线程同步机制：

• WinForms：使用System.Windows.Forms.Control.Invoke/BeginInvoke，或SynchronizationContext.Current
• WPF：使用System.Windows.Threading.Dispatcher（控件自带的Dispatcher属性）

推荐使用SynchronizationContext实现跨框架兼容，修改步骤如下：

修改GetBleDevice类

Imports Windows.Devices.Bluetooth
Imports Windows.Devices.Enumeration
Imports System.Threading

Public Class GetBleDevice
    Private ReadOnly KnownDevices As New ObservableCollection(Of DeviceInformation)()
    Private deviceWatcher As DeviceWatcher

    Public Event GetBleDevices(DevicesBle As ObservableCollection(Of DeviceInformation))

    Private ReadOnly syncContext As SynchronizationContext

    ' 构造函数改为接收SynchronizationContext
    Public Sub New(context As SynchronizationContext)
        syncContext = context
    End Sub

    ' 示例：跨线程触发事件时使用syncContext切换到UI线程
    Private Sub RaiseDeviceEvent()
        syncContext.Post(Sub()
                            RaiseEvent GetBleDevices(KnownDevices)
                        End Sub, Nothing)
    End Sub
End Class

修改Form1初始化代码

Imports System.Collections.ObjectModel
Imports Windows.Devices.Enumeration
Imports Windows.Devices.Bluetooth.GenericAttributeProfile
Imports System.Threading

Public Class Form1
    Dim BleDevices As New ObservableCollection(Of DeviceInformation)()
    Dim BleServices As New ObservableCollection(Of GattDeviceService)()
    Dim BleCharacteristic As New ObservableCollection(Of GattCharacteristic)()

    ' 传递当前UI线程的SynchronizationContext
    WithEvents GetBleDev As New GetBleDevice(SynchronizationContext.Current)
End Class

2. 修复项目引用 #

• 安装NuGet包Microsoft.Windows.SDK.Contracts：该包会自动引入正确版本的Windows Runtime合约，避免手动引用Windows.winmd或旧合约带来的冲突。
• 取消注释Imports System.Collections.ObjectModel：ObservableCollection需要此命名空间。

3. 移除冗余引用 #

删除项目中不必要的引用（如Windows.winmd手动引用、冲突的WinRT合约引用），仅保留：

• WindowsBase.dll（WPF项目）
• System.Runtime.WindowsRuntime.dll
• 通过NuGet引入的Microsoft.Windows.SDK.Contracts相关组件

内容的提问来源于stack exchange，提问作者HJA