WPF暂时禁用用户输入功能 [英] WPF Temporarily disable user input abilities

问题描述

大家好，



我又回来了另一个问题，不过在这个问题上我还没有尝试过。这是因为我真的不知道从哪里开始。



情景

我有一个WPF应用程序基于MVVM原则构建（虽然我认为它不是100％MVVM）。

该应用程序具有以下结构：

Hi Guys,

I'm back again with another question, however on this one I've not actually tried anything yet. This is because I don't really have a clue where to start.

Scenario
I have an WPF application built on MVVM principles (although it is not 100% MVVM I think).
The application has the following structure:

Main Window
    ->ViewContainer (has a menu system in it that creates buttons based on viewmodel)
         -> View A
         -> View B
         -> View C

问题/要求

查看C上有一个按钮在其底层viewmodel上调用命令，现在问题是这是一个长时间运行的命令，我想要做的是阻止用户进行任何用户交互但保持应用程序能够更新。该进程在单独的线程上运行，因此UI可以更新屏幕日志。但是用户仍然可以单击ViewContainer菜单中的按钮并更改视图。我需要防止这种情况，因为在此过程运行时其他选项不应该运行。



目前我可以禁用交互View C，但尝试adhear到MVVM我不知道如何将这种行为应用到父容器？



任何帮助/指针都将不胜感激。



需要更多信息，请问。

Problem/requirement
View C has a button on it that calls a command on its underlying viewmodel, now the issue is this is a long running command and what I want to do is prevent the user from doing any user interaction but keep the application able to update. The process runs on a separate thread so the UI can update an onscreen log. But the user can still click buttons in the ViewContainer menu and change views. I need to prevent this because the other options shouldn't run while this process is running.

Currently I am able to disable interaction View C, but with trying to adhear to MVVM I'm not sure how I can apply this behavior to parent containers?

Any help/pointers would be appreciated.

Need more info, just ask.

推荐答案

尝试为负责更改视图的按钮定义一个命令。 br />
你应该使用一个委托命令。

Try to define a command for the buttons which are responsible for the change of the view.
You should use a Delegate Command for this.

class DelegateCommand : ICommand
    {
        private readonly Predicate<object> _canExecute;
        private readonly Action<object> _execute;

        public event EventHandler CanExecuteChanged;

        public DelegateCommand(Action<object> execute)
        {
            _execute = execute;
        }

        public DelegateCommand(Action<object> execute, Predicate<object> canExecute)
        {
            _execute = execute;
            _canExecute = canExecute;
        }



        public bool CanExecute(object parameter)
        {
            if (_canExecute == null)
            {
                return true;
            }

            return _canExecute(parameter);
        }

        public void Execute(object parameter)
        {
            _execute(parameter);
        }

        public void RaiseCanExecuteChanged()
        {
            if (CanExecuteChanged != null)
            {
                CanExecuteChanged(this, EventArgs.Empty);
            }
        }
    }

它让您有机会定义命令是否可执行或不。



要做到这一点，尝试做这样的事情：

It gives you the opportunity to define whether the command is executable or not.

To do this, try doing something like this:

//
public ICommand SwitchViewCommand { get; set; }
        public void SwitchView(object parameter)
        {
            //Your Logic here.
        }

public bool AllowSwitchView(object parameter)
        {
            //Your Conditions here
        }

并且不要忘记实例化你的命令：

And dont forget to instantiate your command:

SwitchViewCommand = new DelegateCommand(SwitchView, AllowSwitchView);

我希望这会对你有所帮助:)



抱歉我的英文不好。

I hope this will help you :)

And sorry for my bad english.

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