WPF MVVM后台打印数据绑定问题(WPF MVVM background printing da

2019-09-16 13:55发布

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我正在开发使用WPF / MVVM销售应用程序的一个点。 会有在交易生命周期中的许多部分将在后台打印收据。 我已经使用其他例子生成并打印收据只是在后台的罚款。 我打印在后台用户控件，一切看起来不错。

然后，我创建视图模型的控制，因此它可以加载一个交易进行打印。 我开始与2个基本文本框 - “印刷在：MM / DD / YY HH：MM TT”文本标题“客户端接收”，和顶部集流管。

这是调试器是如何呈现的生命周期，当我按下打印按钮：

  • 创建控件的新实例。
  • 创建视图模型的新实例
  • 设置为INPC性文本
  • 运行在控制措施以获得所需的预印刷尺寸
  • 加载打印对话框和检索名称打印队列
  • 缩放控件以适应收据的纸张尺寸（不应该以规模求我当前选定的打印机，作为ImageArea宽度设置相同，我的UC）
  • 重新措施，并安排基础上，“新”缩放图像尺寸的网格
  • 呼吁PrintDialog.PrintVisual - 发送的用户控件
  • 打印机吐出收据 - 没有数据绑定文本
  • 然后，我的调试器将步入得到{_HeaderText; } part of the code - after the control has already been printed. }的代码的一部分 - 该控制已经被打印之后。

有没有办法迫使控制数据绑定之前，它被发送到打印机，而无需加载控制面板并使其可见？ 我希望能够例如，刷信用卡，并把它打印收据在后台签名行，从要求提供详细的CC（或刷卡）一个小的弹出窗口。

有没有更好的方式来实现这一目标？

PrintReceipt方法： 

ClientReceiptView control = new ClientReceiptView(Message);       
System.Windows.Controls.PrintDialog printDlg = new System.Windows.Controls.PrintDialog();
PrintQueue ReceiptPrinter = new LocalPrintServer().GetPrintQueue("CITIZEN CT-S310");
PrintCapabilities PC = ReceiptPrinter.GetPrintCapabilities();
printDlg.PrintQueue = ReceiptPrinter;
control.Measure(new Size(Double.PositiveInfinity, Double.PositiveInfinity));
Size PreGridSize = control.DesiredSize;
double Scale = Math.Min(PC.PageImageableArea.ExtentWidth / PreGridSize.Width, PC.PageImageableArea.ExtentHeight / PreGridSize.Height);
control.LayoutTransform = new System.Windows.Media.ScaleTransform(Scale, Scale);
Size PaperSize = new Size(PC.PageImageableArea.ExtentWidth, Math.Min(PC.PageImageableArea.ExtentHeight, PreGridSize.Height));
control.Measure(PaperSize);
Point ptGrid = new Point(PC.PageImageableArea.OriginWidth, PC.PageImageableArea.OriginHeight);
control.Arrange(new Rect(ptGrid, PaperSize));
printDlg.PrintVisual(control, "My App");

和视图构造函数（带参数） 

public ClientReceiptView(string Header)
{
    InitializeComponent();
    vm = new ClientReceiptViewModel(Header);
    this.DataContext = vm;
}

而视图模型： 

public class ClientReceiptViewModel : ViewModelBase
{
    #region Properties

    private string _HeaderText;

    public string HeaderText
    {
        get { return _HeaderText; }
        set { _HeaderText = value; OnPropertyChanged("HeaderText"); }
    }

    private int _TripID;

    public int TripID
    {
        get { return _TripID; }
        set { _TripID = value; OnPropertyChanged("TripID"); }
    }

    private string _PrintedOn;

    public string PrintedOn
    {
        get { return _PrintedOn; }
        set { _PrintedOn = value; OnPropertyChanged("PrintedOn"); }
    }

    #endregion

    public ClientReceiptViewModel(string Header)
    {
        HeaderText = Header;
        TripID = 2220013;
        PrintedOn = "Printed: " + DateTime.Now.ToString("MM/dd/yy hh:mm tt");
    }
}

编辑：从与OnPropertyChanged（“的HeaderText”）休息绑定/创建调用堆栈： 

Namespace.Main.POS.Receipts.ClientReceiptViewModel.PrintedOn.set(string value) Line 38  C#
Namespace.Main.POS.Receipts.ClientReceiptViewModel.SetData(string Header) Line 79 + 0x4f bytes  C#
Namespace.Main.POS.Receipts.ClientReceiptView.ClientReceiptView(string Header) Line 28 + 0x13 bytes C#
Namespace.Main.POS.Receipts.PrintReceipt.PrintClientReceipt(string Message) Line 12 + 0x1e bytes    C#
Namespace.Main.MainWindowView.button1_Click(object sender, System.Windows.RoutedEventArgs e) Line 23 + 0xb bytes    C#
PresentationCore.dll!System.Windows.RoutedEventHandlerInfo.InvokeHandler(object target, System.Windows.RoutedEventArgs routedEventArgs) + 0x78 bytes    
PresentationCore.dll!System.Windows.EventRoute.InvokeHandlersImpl(object source, System.Windows.RoutedEventArgs args, bool reRaised) + 0xbe bytes   
PresentationCore.dll!System.Windows.UIElement.RaiseEventImpl(System.Windows.DependencyObject sender, System.Windows.RoutedEventArgs args) + 0x79 bytes  
PresentationCore.dll!System.Windows.UIElement.RaiseEvent(System.Windows.RoutedEventArgs e) + 0x17 bytes 
PresentationFramework.dll!System.Windows.Controls.Primitives.ButtonBase.OnClick() + 0x4b bytes  
PresentationFramework.dll!System.Windows.Controls.Button.OnClick() + 0x4d bytes 
PresentationFramework.dll!System.Windows.Controls.Primitives.ButtonBase.OnMouseLeftButtonUp(System.Windows.Input.MouseButtonEventArgs e) + 0x9e bytes   
PresentationCore.dll!System.Windows.UIElement.OnMouseLeftButtonUpThunk(object sender, System.Windows.Input.MouseButtonEventArgs e) + 0x6c bytes 
PresentationCore.dll!System.Windows.Input.MouseButtonEventArgs.InvokeEventHandler(System.Delegate genericHandler, object genericTarget) + 0x31 bytes    
PresentationCore.dll!System.Windows.RoutedEventArgs.InvokeHandler(System.Delegate handler, object target) + 0x29 bytes  
PresentationCore.dll!System.Windows.RoutedEventHandlerInfo.InvokeHandler(object target, System.Windows.RoutedEventArgs routedEventArgs) + 0x3e bytes    
PresentationCore.dll!System.Windows.EventRoute.InvokeHandlersImpl(object source, System.Windows.RoutedEventArgs args, bool reRaised) + 0xbe bytes   
PresentationCore.dll!System.Windows.UIElement.ReRaiseEventAs(System.Windows.DependencyObject sender, System.Windows.RoutedEventArgs args, System.Windows.RoutedEvent newEvent) + 0x114 bytes    
PresentationCore.dll!System.Windows.UIElement.OnMouseUpThunk(object sender, System.Windows.Input.MouseButtonEventArgs e) + 0xc5 bytes   
PresentationCore.dll!System.Windows.Input.MouseButtonEventArgs.InvokeEventHandler(System.Delegate genericHandler, object genericTarget) + 0x31 bytes    
PresentationCore.dll!System.Windows.RoutedEventArgs.InvokeHandler(System.Delegate handler, object target) + 0x29 bytes  
PresentationCore.dll!System.Windows.RoutedEventHandlerInfo.InvokeHandler(object target, System.Windows.RoutedEventArgs routedEventArgs) + 0x3e bytes    
PresentationCore.dll!System.Windows.EventRoute.InvokeHandlersImpl(object source, System.Windows.RoutedEventArgs args, bool reRaised) + 0xbe bytes   
PresentationCore.dll!System.Windows.UIElement.RaiseEventImpl(System.Windows.DependencyObject sender, System.Windows.RoutedEventArgs args) + 0x79 bytes  
PresentationCore.dll!System.Windows.UIElement.RaiseTrustedEvent(System.Windows.RoutedEventArgs args) + 0x41 bytes   
PresentationCore.dll!System.Windows.UIElement.RaiseEvent(System.Windows.RoutedEventArgs args, bool trusted) + 0x2c bytes    
PresentationCore.dll!System.Windows.Input.InputManager.ProcessStagingArea() + 0x1ff bytes   
PresentationCore.dll!System.Windows.Input.InputManager.ProcessInput(System.Windows.Input.InputEventArgs input) + 0x45 bytes 
PresentationCore.dll!System.Windows.Input.InputProviderSite.ReportInput(System.Windows.Input.InputReport inputReport) + 0x62 bytes  
PresentationCore.dll!System.Windows.Interop.HwndMouseInputProvider.ReportInput(System.IntPtr hwnd, System.Windows.Input.InputMode mode, int timestamp, System.Windows.Input.RawMouseActions actions, int x, int y, int wheel) + 0x2c2 bytes 
PresentationCore.dll!System.Windows.Interop.HwndMouseInputProvider.FilterMessage(System.IntPtr hwnd, MS.Internal.Interop.WindowMessage msg, System.IntPtr wParam, System.IntPtr lParam, ref bool handled) + 0x67d bytes 
PresentationCore.dll!System.Windows.Interop.HwndSource.InputFilterMessage(System.IntPtr hwnd, int msg, System.IntPtr wParam, System.IntPtr lParam, ref bool handled) + 0x75 bytes   
WindowsBase.dll!MS.Win32.HwndWrapper.WndProc(System.IntPtr hwnd, int msg, System.IntPtr wParam, System.IntPtr lParam, ref bool handled) + 0xbe bytes    
WindowsBase.dll!MS.Win32.HwndSubclass.DispatcherCallbackOperation(object o) + 0x7d bytes    
WindowsBase.dll!System.Windows.Threading.ExceptionWrapper.InternalRealCall(System.Delegate callback, object args, int numArgs) + 0x53 bytes 
WindowsBase.dll!MS.Internal.Threading.ExceptionFilterHelper.TryCatchWhen(object source, System.Delegate method, object args, int numArgs, System.Delegate catchHandler) + 0x42 bytes    
WindowsBase.dll!System.Windows.Threading.Dispatcher.InvokeImpl(System.Windows.Threading.DispatcherPriority priority, System.TimeSpan timeout, System.Delegate method, object args, int numArgs) + 0xb4 bytes    
WindowsBase.dll!MS.Win32.HwndSubclass.SubclassWndProc(System.IntPtr hwnd, int msg, System.IntPtr wParam, System.IntPtr lParam) + 0x104 bytes    
[Native to Managed Transition]  
[Managed to Native Transition]  
WindowsBase.dll!System.Windows.Threading.Dispatcher.PushFrameImpl(System.Windows.Threading.DispatcherFrame frame) + 0xc1 bytes  
WindowsBase.dll!System.Windows.Threading.Dispatcher.PushFrame(System.Windows.Threading.DispatcherFrame frame) + 0x49 bytes  
PresentationFramework.dll!System.Windows.Application.RunDispatcher(object ignore) + 0x5b bytes  
PresentationFramework.dll!System.Windows.Application.RunInternal(System.Windows.Window window) + 0x74 bytes 
PresentationFramework.dll!System.Windows.Application.Run(System.Windows.Window window) + 0x2b bytes 
PresentationFramework.dll!System.Windows.Application.Run() + 0x1b bytes 
Namespace.App.Main() + 0x5e bytes   C#
[Native to Managed Transition]  
[Managed to Native Transition]  
mscorlib.dll!System.AppDomain.nExecuteAssembly(System.Reflection.RuntimeAssembly assembly, string[] args) + 0x9 bytes   
mscorlib.dll!System.Runtime.Hosting.ManifestRunner.Run(bool checkAptModel) + 0x6e bytes 
mscorlib.dll!System.Runtime.Hosting.ManifestRunner.ExecuteAsAssembly() + 0x90 bytes 
mscorlib.dll!System.Runtime.Hosting.ApplicationActivator.CreateInstance(System.ActivationContext activationContext, string[] activationCustomData) + 0x65 bytes 
mscorlib.dll!System.Runtime.Hosting.ApplicationActivator.CreateInstance(System.ActivationContext activationContext) + 0xd bytes 
mscorlib.dll!System.Activator.CreateInstance(System.ActivationContext activationContext) + 0x44 bytes   
Microsoft.VisualStudio.HostingProcess.Utilities.dll!Microsoft.VisualStudio.HostingProcess.HostProc.RunUsersAssemblyDebugInZone() + 0x23 bytes   
mscorlib.dll!System.Threading.ThreadHelper.ThreadStart_Context(object state) + 0x63 bytes   
mscorlib.dll!System.Threading.ExecutionContext.Run(System.Threading.ExecutionContext executionContext, System.Threading.ContextCallback callback, object state, bool ignoreSyncCtx) + 0xb0 bytes    
mscorlib.dll!System.Threading.ExecutionContext.Run(System.Threading.ExecutionContext executionContext, System.Threading.ContextCallback callback, object state) + 0x2c bytes    
mscorlib.dll!System.Threading.ThreadHelper.ThreadStart() + 0x44 bytes   
[Native to Managed Transition]

再经过printDlg.PrintVisual（控制，“我的应用”）; 发出后，收据打印出来，然后在断点获取调用堆栈{返回_PrintedOn; }： 

Namespace.Main.POS.Receipts.ClientReceiptViewModel.PrintedOn.get() Line 37  C#
[Native to Managed Transition]  
PresentationFramework.dll!MS.Internal.Data.PropertyPathWorker.GetValue(object item, int level) + 0x108 bytes    
PresentationFramework.dll!MS.Internal.Data.PropertyPathWorker.RawValue(int k) + 0x4a bytes  
PresentationFramework.dll!MS.Internal.Data.PropertyPathWorker.RawValue() + 0x12 bytes   
PresentationFramework.dll!MS.Internal.Data.ClrBindingWorker.RawValue() + 0x11 bytes 
PresentationFramework.dll!System.Windows.Data.BindingExpression.TransferValue(object newValue, bool isASubPropertyChange) + 0xa7 bytes  
PresentationFramework.dll!System.Windows.Data.BindingExpression.Activate(object item) + 0x194 bytes 
PresentationFramework.dll!System.Windows.Data.BindingExpression.AttachToContext(System.Windows.Data.BindingExpression.AttachAttempt attempt) + 0x38d bytes  
PresentationFramework.dll!System.Windows.Data.BindingExpression.MS.Internal.Data.IDataBindEngineClient.AttachToContext(bool lastChance) + 0x19 bytes    
PresentationFramework.dll!MS.Internal.Data.DataBindEngine.Task.Run(bool lastChance) + 0x31 bytes    
PresentationFramework.dll!MS.Internal.Data.DataBindEngine.Run(object arg) + 0xb6 bytes  
WindowsBase.dll!System.Windows.Threading.ExceptionWrapper.InternalRealCall(System.Delegate callback, object args, int numArgs) + 0x53 bytes 
WindowsBase.dll!MS.Internal.Threading.ExceptionFilterHelper.TryCatchWhen(object source, System.Delegate method, object args, int numArgs, System.Delegate catchHandler) + 0x42 bytes    
WindowsBase.dll!System.Windows.Threading.DispatcherOperation.InvokeImpl() + 0x8d bytes  
WindowsBase.dll!System.Windows.Threading.DispatcherOperation.InvokeInSecurityContext(object state) + 0x38 bytes 
mscorlib.dll!System.Threading.ExecutionContext.runTryCode(object userData) + 0x51 bytes 
[Native to Managed Transition]  
[Managed to Native Transition]  
mscorlib.dll!System.Threading.ExecutionContext.RunInternal(System.Threading.ExecutionContext executionContext, System.Threading.ContextCallback callback, object state) + 0x6a bytes    
mscorlib.dll!System.Threading.ExecutionContext.Run(System.Threading.ExecutionContext executionContext, System.Threading.ContextCallback callback, object state, bool ignoreSyncCtx) + 0x7e bytes    
mscorlib.dll!System.Threading.ExecutionContext.Run(System.Threading.ExecutionContext executionContext, System.Threading.ContextCallback callback, object state) + 0x2c bytes    
WindowsBase.dll!System.Windows.Threading.DispatcherOperation.Invoke() + 0x68 bytes  
WindowsBase.dll!System.Windows.Threading.Dispatcher.ProcessQueue() + 0x15e bytes    
WindowsBase.dll!System.Windows.Threading.Dispatcher.WndProcHook(System.IntPtr hwnd, int msg, System.IntPtr wParam, System.IntPtr lParam, ref bool handled) + 0x63 bytes 
WindowsBase.dll!MS.Win32.HwndWrapper.WndProc(System.IntPtr hwnd, int msg, System.IntPtr wParam, System.IntPtr lParam, ref bool handled) + 0xbe bytes    
WindowsBase.dll!MS.Win32.HwndSubclass.DispatcherCallbackOperation(object o) + 0x7d bytes    
WindowsBase.dll!System.Windows.Threading.ExceptionWrapper.InternalRealCall(System.Delegate callback, object args, int numArgs) + 0x53 bytes 
WindowsBase.dll!MS.Internal.Threading.ExceptionFilterHelper.TryCatchWhen(object source, System.Delegate method, object args, int numArgs, System.Delegate catchHandler) + 0x42 bytes    
WindowsBase.dll!System.Windows.Threading.Dispatcher.InvokeImpl(System.Windows.Threading.DispatcherPriority priority, System.TimeSpan timeout, System.Delegate method, object args, int numArgs) + 0xb4 bytes    
WindowsBase.dll!MS.Win32.HwndSubclass.SubclassWndProc(System.IntPtr hwnd, int msg, System.IntPtr wParam, System.IntPtr lParam) + 0x104 bytes    
[Native to Managed Transition]  
[Managed to Native Transition]  
WindowsBase.dll!System.Windows.Threading.Dispatcher.PushFrameImpl(System.Windows.Threading.DispatcherFrame frame) + 0xc1 bytes  
WindowsBase.dll!System.Windows.Threading.Dispatcher.PushFrame(System.Windows.Threading.DispatcherFrame frame) + 0x49 bytes  
PresentationFramework.dll!System.Windows.Application.RunDispatcher(object ignore) + 0x5b bytes  
PresentationFramework.dll!System.Windows.Application.RunInternal(System.Windows.Window window) + 0x74 bytes 
PresentationFramework.dll!System.Windows.Application.Run(System.Windows.Window window) + 0x2b bytes 
PresentationFramework.dll!System.Windows.Application.Run() + 0x1b bytes 
Namespace.App.Main() + 0x5e bytes   C#
[Native to Managed Transition]  
[Managed to Native Transition]  
mscorlib.dll!System.AppDomain.nExecuteAssembly(System.Reflection.RuntimeAssembly assembly, string[] args) + 0x9 bytes   
mscorlib.dll!System.Runtime.Hosting.ManifestRunner.Run(bool checkAptModel) + 0x6e bytes 
mscorlib.dll!System.Runtime.Hosting.ManifestRunner.ExecuteAsAssembly() + 0x90 bytes 
mscorlib.dll!System.Runtime.Hosting.ApplicationActivator.CreateInstance(System.ActivationContext activationContext, string[] activationCustomData) + 0x65 bytes 
mscorlib.dll!System.Runtime.Hosting.ApplicationActivator.CreateInstance(System.ActivationContext activationContext) + 0xd bytes 
mscorlib.dll!System.Activator.CreateInstance(System.ActivationContext activationContext) + 0x44 bytes   
Microsoft.VisualStudio.HostingProcess.Utilities.dll!Microsoft.VisualStudio.HostingProcess.HostProc.RunUsersAssemblyDebugInZone() + 0x23 bytes   
mscorlib.dll!System.Threading.ThreadHelper.ThreadStart_Context(object state) + 0x63 bytes   
mscorlib.dll!System.Threading.ExecutionContext.Run(System.Threading.ExecutionContext executionContext, System.Threading.ContextCallback callback, object state, bool ignoreSyncCtx) + 0xb0 bytes    
mscorlib.dll!System.Threading.ExecutionContext.Run(System.Threading.ExecutionContext executionContext, System.Threading.ContextCallback callback, object state) + 0x2c bytes    
mscorlib.dll!System.Threading.ThreadHelper.ThreadStart() + 0x44 bytes   
[Native to Managed Transition]

Answer 1:

使用调度在以后排队打印作业的DispatcherPriority比DataBind 。 通过这种方式，打印作业做之前你所有的数据绑定得到处理。 

Dispatcher.BeginInvoke(DispatcherPriority.Loaded,
    new Action(delegate() { printDlg.PrintVisual(control, "My App"); } ));


Answer 2:

我不知道是什么触发了最初的绑定更新（你可以从你的调用栈告诉？）。 我很想找出了。

它周围的一种方式是在它已经设置为视图上下文在你的视图模型设定值。 也许的PropertyChanged通知将强制绑定更新例如： 

public ClientReceiptView(string Header)
{
    InitializeComponent();
    vm = new ClientReceiptViewModel();
    this.DataContext = vm;
    vm.SetHeader(Header);
}

只是猜测，但。 ：/



文章来源: WPF MVVM background printing databinding issue
标签： c# wpf data-binding mvvm printing
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