如何在進行中的對話框中正確調用后台線程？

Question

我們應用程序的主窗口將打開一個正在進行的對話框，該對話框應調用一個后台線程。 該對話框應出現，直到線程完成：

var dialog = new WorkInProgressDialog();
dialog = ShowDialg;

現在的問題是在哪里/如何在WorkInProgressDialog構造函數中調用線程？ 如果在構造函數中調用該對話框，則在線程完成之前該對話框不可見。

線程完成后，對話框也應自動關閉。

Answer 1

這是一個希望對您有所幫助的示例。 WorkInProgressDialog的一些簡單標記：

<Window x:Class="WorkInProgressExample.WorkInProgressDialog"
    xmlns="http://schemas.microsoft.com/winfx/2006/xaml/presentation"
    xmlns:x="http://schemas.microsoft.com/winfx/2006/xaml"
    Title="WorkInProgressDialog" Height="100" Width="300" WindowStyle="None" 
    ResizeMode="NoResize" WindowStartupLocation="CenterScreen">
    <Border BorderThickness="3" CornerRadius="5" BorderBrush="Black" Padding="10">
        <Grid>
            <Grid.RowDefinitions>
                <RowDefinition Height="*"></RowDefinition>
                <RowDefinition Height="Auto"></RowDefinition>
                <RowDefinition Height="Auto"></RowDefinition>
                <RowDefinition Height="*"></RowDefinition>
            </Grid.RowDefinitions>            

            <TextBlock Grid.Row="1" Name="WorkProgressTextBlock">Work in progress...</TextBlock>
            <ProgressBar Grid.Row="2" Height="30" Name="WorkProgressBar"></ProgressBar>
        </Grid>
    </Border>
</Window>

然后在后面的代碼中：

private bool _closeAuthorised = false;

public WorkInProgressDialog()
{
    InitializeComponent();

    WorkProgressBar.Maximum = 10;
    WorkProgressBar.Minimum = 0;

    Task.Factory.StartNew(() =>
    {
        // Do whatever processing you need to here
        for (int i = 0; i < 10; i++)
        {
            // Any updates to the UI need to be done on the UI thread
            this.Dispatcher.Invoke((Action)(() =>
            {
                WorkProgressBar.Value = i;
            }));

            Thread.Sleep(1000);
        }

        // Set the DialogResult and hence close, also on the UI thread
        this.Dispatcher.Invoke((Action)(() =>
        {
            _closeAuthorised = true;
            this.DialogResult = true;
        }));

    });
}

protected override void OnClosing(System.ComponentModel.CancelEventArgs e)
{
    // If the user uses ALT+F4 to try andclose the loading dialog, this will cancel it
    if (!_closeAuthorised)
        e.Cancel = true;
    base.OnClosing(e);
}

然后在您要使用它的地方：

var dialog = new WorkInProgressDialog();
bool? result = dialog.ShowDialog();