C＃：查询/计算过程中禁用按钮 [英] C#: Disable button during search/calculation

问题描述

我有我想要在搜索过程中禁用搜索按钮搜索对话框。这是当前的代码，但该按钮没有得到停用

查看：

 <按钮内容=搜索
命令={结合StartSearchCommand}
 IsEnabled ={结合IsNotSearching}/> 
  

视图模型：

 私人布尔_isNotSearching; 
公共BOOL IsNotSearching 
 {
 {返回_isNotSearching; } 
组
 {
 _isNotSearching =价值; 
 OnPropertyChanged（IsNotSearching）; 
} 
} 
 
 
私人RelayCommand<对象> _startSearchCommand; 
公众的ICommand StartSearchCommand 
 {
得到
 {
如果（_startSearchCommand == NULL）
 _startSearchCommand =新RelayCommand<对象>（P => ExecuteSearch （））; 
返回_startSearchCommand; 
} 
} 
私人无效ExecuteSearch（）
 {
 IsNotSearching = FALSE; 
 //做一些搜索在这里
 IsNotSearching = TRUE; 
} 
  

解决方案

我做了一个 AsyncDelegateCommand 出于这个原因（基于著名 DelegateCommand ），它在执行命令操作期间内禁止命令（UI）：

 公共类AsyncDelegateCommand：ICommand的
 {
只读动作<对象> _执行; 
只读谓词<对象> _canExecute; 
布尔_running; 
 
公共事件的EventHandler CanExecuteChanged; 
 
公共AsyncDelegateCommand（动作<对象>执行，谓语<对象> canExecute = NULL）
 {
 _execute =执行; 
 _canExecute = canExecute; 
} 
 
公共BOOL CanExecute（对象参数）
 {
回报率（_canExecute == NULL真：？_canExecute（参数））及和放大器; ！_running; 
} 
 
公共异步执行无效（对象参数）
 {
 _running = TRUE; 
更新（）; 
等待Task.Run（（）=> _execute（参数））; 
 _running = FALSE; 
更新（）; 
} 
 
公共无效更新（）
 {
如果（CanExecuteChanged！= NULL）
 CanExecuteChanged（这一点，EventArgs.Empty）; 
} 
} 
  

XAML：

 <按钮命令={结合SomeCommand}... /> 
  

视图模型：

  AsyncDelegateCommand SomeCommand {搞定; } 
 
 //在构造函数中
 SomeCommand =新AsyncDelegateCommand（O => {Thread.sleep代码（5000）;}）; //代码运行
  

I have a search dialog where I want to disable the search button during the search. This is the current code but the button does not get deactivated

View:

<Button Content="Search" 
        Command="{Binding StartSearchCommand}" 
        IsEnabled="{Binding IsNotSearching}" />

ViewModel:

private bool _isNotSearching;
public bool IsNotSearching
{
    get { return _isNotSearching; }
    set
    {
        _isNotSearching = value;
        OnPropertyChanged("IsNotSearching");
    }
}


private RelayCommand<object> _startSearchCommand;
public ICommand StartSearchCommand
{
    get
    {
        if (_startSearchCommand == null)
            _startSearchCommand = new RelayCommand<object>(p => ExecuteSearch());
        return _startSearchCommand;
    }
}
private void ExecuteSearch()
{
    IsNotSearching = false;
    //do some searching here
    IsNotSearching = true;
}

解决方案

I've made an AsyncDelegateCommand for that reason (based on famous DelegateCommand), it internally disable command (in UI) during executing command action:

public class AsyncDelegateCommand : ICommand
{
    readonly Action<object> _execute;
    readonly Predicate<object> _canExecute;
    bool _running;

    public event EventHandler CanExecuteChanged;

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

    public bool CanExecute(object parameter)
    {
        return (_canExecute == null ? true : _canExecute(parameter)) && !_running;
    }

    public async void Execute(object parameter)
    {
        _running = true;
        Update();
        await Task.Run(() => _execute(parameter));
        _running = false;
        Update();
    }

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

xaml:

<Button Command="{Binding SomeCommand}" .../>

ViewModel:

AsyncDelegateCommand SomeCommand { get; }

    // in constructor
    SomeCommand = new AsyncDelegateCommand(o =>  { Thread.Sleep(5000); }); // code to run

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