WPF ProgressBar显示进度（五）

来源：互联网发布：live2d mac有哪些编辑：程序博客网时间：2024/05/16 06:54

在这里，我们将控制进度条的进度显示，功能很简单，通过两个按钮“Start”和“Stop”分别控制进度条的加载与暂停，当Start可用时，Stop不可用；反之，当Start不可用时，Stop可用。

我们知道，当UI绑定Command时会订阅CanExecuteChanged事件，而该事件会一直监测UI的状态并实时调用CanExecute方法返回其状态，同样的，我们在之前MVVM的基础上来实现这一功能。

1、在Model里添加Progress类

class Progress{    public double Minimum { get; set; }    public double Maximum { get; set; }    public double Value { get; set; }    public string Text { get; set; }}

2、在Command里添加两个类，RelayCommandGo和RelayCommandStop

class RelayCommandGo : ICommand{    private Action _execute;    private Func<bool> _canExecute;    public RelayCommandGo(Action execute, Func<bool> canExecute)    {        this._execute = execute;        this._canExecute = canExecute;    }    public event EventHandler CanExecuteChanged    {        add { CommandManager.RequerySuggested += value; }        remove { CommandManager.RequerySuggested -= value; }    }    public bool CanExecute(object parameter)    {        return this._canExecute();    }    public void Execute(object parameter)    {        this._execute();    }}class RelayCommandStop : ICommand{    private Action _execute;    private Func<bool> _canExecute;    public RelayCommandStop(Action execute, Func<bool> canExecute)    {        this._execute = execute;        this._canExecute = canExecute;    }    public event EventHandler CanExecuteChanged    {        add { CommandManager.RequerySuggested += value; }        remove { CommandManager.RequerySuggested -= value; }    }    public bool CanExecute(object parameter)    {        return this._canExecute();    }    public void Execute(object parameter)    {        this._execute();    }}

3、在ViewModel里添加ProgressViewModel类

namespace MVVM3{    class ProgressViewModel : INotifyPropertyChanged    {        public event PropertyChangedEventHandler PropertyChanged;        public Progress Progress { get; set; }        /// <summary>        /// 最小值        /// </summary>        public double Minimum        {            get { return this.Progress.Minimum; }            set            {                this.Progress.Minimum = value;                RaisePropertyChanged("Minimum");            }        }        /// <summary>        /// 最大值        /// </summary>        public double Maximum        {            get { return this.Progress.Maximum; }            set            {                this.Progress.Maximum = value;                RaisePropertyChanged("Maximum");            }        }        /// <summary>        /// 当前数值        /// </summary>        public double Value        {            get { return this.Progress.Value; }            set            {                this.Progress.Value = value;                RaisePropertyChanged("Value");            }        }        /// <summary>        /// 当前数值        /// </summary>        public string Text        {            get { return this.Progress.Text; }            set            {                this.Progress.Text = value;                RaisePropertyChanged("Text");            }        }        /// <summary>        /// 是否可用的状态        /// </summary>        public bool IsEnabledStart { get; set; }        /// <summary>        /// 是否可用的状态        /// </summary>        public bool IsEnabledStop { get; set; }        private void RaisePropertyChanged(string propertyName)        {            if (this.PropertyChanged != null)            {                this.PropertyChanged(this, new PropertyChangedEventArgs(propertyName));            }        }        public RelayCommandGo CommandGo { get; set; }        public RelayCommandStop CommandStop { get; set; }        /// <summary>        /// 线程同步事件        /// </summary>        private ManualResetEvent _manualReset;        /// <summary>        /// 线程        /// </summary>        private Thread _thread;        public ProgressViewModel()        {            this.Progress = new Progress() { Maximum = 100 };            this._manualReset = new ManualResetEvent(false);            this.IsEnabledStart = true;            this.IsEnabledStop = false;            this.CommandGo = new RelayCommandGo(StartProgress, EnabledStart);            this.CommandStop = new RelayCommandStop(StopProgress, EnabledStop);        }        /// <summary>        /// 开启线程        /// </summary>        private void StartProgress()        {            this._manualReset.Set();            if (_thread == null)            {                _thread = new Thread(new ThreadStart(() =>                {                    for (int i = 1; i <= 100; i++)                    {                        this._manualReset.WaitOne();                        this.Value = i;                        this.Text = string.Format("{0}%", i);                        Thread.Sleep(200);                    }                }));                _thread.Start();            }            this.IsEnabledStop = this.IsEnabledStart;            this.IsEnabledStart = !this.IsEnabledStart;        }        /// <summary>        /// 停止线程的执行        /// </summary>        private void StopProgress()        {            this._manualReset.Reset();            this.IsEnabledStart = this.IsEnabledStop;            this.IsEnabledStop = !this.IsEnabledStop;        }        /// <summary>        /// 确定此命令是否可以在当前状态下执行        /// </summary>        /// <returns></returns>        private bool EnabledStart()        {            return this.IsEnabledStart;        }        /// <summary>        /// 确定此命令是否可以在当前状态下执行        /// </summary>        /// <returns></returns>        private bool EnabledStop()        {            return this.IsEnabledStop;        }    }}

4、在View里添加xaml

<Window x:Class="MVVM3.MainWindow"        xmlns="http://schemas.microsoft.com/winfx/2006/xaml/presentation"        xmlns:x="http://schemas.microsoft.com/winfx/2006/xaml"        xmlns:local="clr-namespace:MVVM3"        Title="MainWindow" Height="350" Width="525">    <Window.Resources>        <local:ProgressViewModel x:Key="progressViewModel"></local:ProgressViewModel>    </Window.Resources>    <Window.DataContext>        <Binding Source="{StaticResource ResourceKey=progressViewModel}"></Binding>    </Window.DataContext>    <StackPanel>        <TextBlock x:Name="tb" Height="23" Text="{Binding Text}"></TextBlock>        <ProgressBar x:Name="pb" Height="20" Minimum="{Binding Minimum}" Maximum="{Binding Maximum}" Value="{Binding Value}"></ProgressBar>        <StackPanel Orientation="Horizontal" HorizontalAlignment="Center">            <Button Content="Start" Width="72" Height="23" Margin="5" Command="{Binding CommandGo}"></Button>            <Button Content="Stop" Width="72" Height="23" Margin="5" Command="{Binding CommandStop}"></Button>        </StackPanel>    </StackPanel></Window>

程序运行如下图所示：

(1)、程序启动时

(2)、点击Start

(3)、点击Stop

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