Wpf 异步方法更新进度条
前面用了Background方法来更新进度条，这次用更好用异步方法来更新进度条
先看效果
cs代码
1 using System; 2 using System.Collections.Generic; 3 using System.IO; 4 using System.Linq; 5 using System.Text; 6 using System.Threading; 7 using System.Threading.Tasks; 8 using System.Windows; 9 using System.Windows.Controls; 10 using System.Windows.Data; 11 using System.Windows.Documents; 12 using System.Windows.Input; 13 using System.Windows.Media; 14 using System.Windows.Media.Imaging; 15 using System.Windows.Navigation; 16 using System.Windows.Shapes; 17 18 namespace Wpf中的异步操作 19 { 20 /// <summary> 21 /// MainWindow.xaml 的交互逻辑 22 /// </summary> 23 public partial class MainWindow : Window 24 { 25 public MainWindow() 26 { 27 InitializeComponent(); 28 } 29 30 private void Button_Click(object sender, RoutedEventArgs e) 31 { 32 Update(); 33 } 34 35 private async void Button_Click1(object sender, RoutedEventArgs e) 36 { 37 text.Text = "0"; 38 var result = await UpdateAsync();//等待方法完成 39 text.Text = result.ToString(); 40 MessageBox.Show("异步方法完成后");//在方法完成后输出 41 } 42 43 private void Button_Click2(object sender, RoutedEventArgs e) 44 { 45 text.Text = "0"; 46 UpdateAsync().ContinueWith(t => 47 { 48 //UI线程调用更新文字 49 Dispatcher.Invoke(() => 50 { 51 text.Text = t.Result.ToString(); 52 }); 53 MessageBox.Show("异步方法完成后"); 54 });//没有等待，继续往下执行 55 56 MessageBox.Show("异步方法完成前");//在方法完成前输出 57 } 58 59 /// <summary> 60 /// 同步方法更新进度条 61 /// </summary> 62 private void Update() 63 { 64 for (int i = 0; i < 100; i++) 65 { 66 Thread.Sleep(50); 67 bar.Value = i + 1; 68 } 69 } 70 71 /// <summary> 72 /// 异步方法更新进度条 73 /// </summary> 74 /// <returns></returns> 75 private async Task<int> UpdateAsync() 76 { 77 var num = 0; 78 for (int i = 0; i < 100; i++) 79 { 80 await Task.Delay(50);//等待 81 bar.Value = i + 1; 82 num += i; 83 } 84 return num; 85 } 86 } 87 }
xaml代码
1 <Window 2 x:Class="Wpf中的异步操作.MainWindow" 3 xmlns="http://schemas.microsoft.com/winfx/2006/xaml/presentation" 4 xmlns:x="http://schemas.microsoft.com/winfx/2006/xaml" 5 xmlns:d="http://schemas.microsoft.com/expression/blend/2008" 6 xmlns:local="clr-namespace:Wpf中的异步操作" 7 xmlns:mc="http://schemas.openxmlformats.org/markup-compatibility/2006" 8 Title="MainWindow" 9 Width="800" 10 Height="450" 11 mc:Ignorable="d"> 12 <Grid> 13 <Grid.ColumnDefinitions> 14 <ColumnDefinition /> 15 </Grid.ColumnDefinitions> 16 <StackPanel Orientation="Vertical"> 17 <Button 18 Width="200" 19 Height="50" 20 Click="Button_Click" 21 Content="同步方法" /> 22 <Button 23 Width="200" 24 Height="50" 25 Click="Button_Click1" 26 Content="异步方法1" /> 27 <Button 28 Width="200" 29 Height="50" 30 Click="Button_Click2" 31 Content="异步方法2" /> 32 <TextBlock 33 HorizontalAlignment="Center" 34 FontSize="50" 35 Text="{Binding Path=Value, ElementName=bar}" /> 36 <ProgressBar x:Name="bar" Height="50" /> 37 <TextBlock 38 x:Name="text" 39 HorizontalAlignment="Center" 40 FontSize="50" 41 Text="0" /> 42 </StackPanel> 43 </Grid> 44 </Window>
