Question

我有一个弹出窗口，每当用户键入不允许的字符时，就会弹出一个窗口，然后我将延迟时间保持在屏幕上6秒钟，而我想做的就是当用户键入允许的字符时，弹出窗口应立即消失，并且当用户再次键入不允许的字符时，它应显示弹出窗口，如果用户未键入任何内容，则等待6秒。我已经这样做了，但是它不起作用，弹出窗口出现了，然后如果我输入允许的字符，它会将IsOpen设置为false，但是当用户再次键入不允许的字符时，延迟不再起作用，它将在随机秒内关闭弹出窗口。我该如何解决这个问题，或者有什么更好的方法呢？

    private async void txtName_TextChanged(object sender, EventArgs e)
    {
        if (Regex.IsMatch(txtName.Text, @"[\\/:*?""<>|]"))
        {
            string pattern = @"[\\/:*?""<>|]";
            Regex regex = new Regex(pattern);
            txtName.Text = regex.Replace(txtName.Text, "");

            if (AlertPopup.IsOpen == false)
            {
                AlertPopup.IsOpen = true;
                await Task.Delay(6000); //It stays true for 6 seconds
                AlertPopup.IsOpen = false;
            }
        }
        else
        {
            AlertPopup.IsOpen = false;
        }
    }

这是弹出的XAML代码：

    <Popup AllowsTransparency="True" PlacementTarget="{Binding ElementName=txtName}"
           Placement="Bottom" x:Name="AlertPopup">
        <Border Margin="0,0,35,35" Background="#272C30" BorderBrush="#6C757D"
                BorderThickness="2" CornerRadius="10">
            <Border.Effect>
                <DropShadowEffect Color="Black" BlurRadius="35" Direction="315"
                                  ShadowDepth="16" Opacity="0.2"/>
            </Border.Effect>
            <TextBlock Padding="8,3,8,5" Foreground="#ADB5BD" Background="Transparent" FontSize="12"
            Text="The file name can't contain any of the following&#x0a;characters :   \  / : * ? &quot; &lt; &gt; |"/>
        </Border>
    </Popup>

Answer 1

Task.Delay接受CancellationToken，您可以在每次击键时使用“取消”任务。像这样：

private CancellationTokenSource cts;
private async void txtName_TextChanged(object sender, EventArgs e)
{
    if (cts != null)
    {
        cts.Cancel();
        cts.Dispose();
    }
    cts = new CancellationTokenSource();

    if (Regex.IsMatch(txtName.Text, @"[\\/:*?""<>|]"))
    {
        string pattern = @"[\\/:*?""<>|]";
        Regex regex = new Regex(pattern);
        txtName.TextChanged -= txtName_TextChanged;
        txtName.Text = regex.Replace(txtName.Text, "");
        txtName.TextChanged += txtName_TextChanged;

        if (AlertPopup.IsOpen == false)
        {
            AlertPopup.IsOpen = true;
            try
            {
                await Task.Delay(6000, cts.Token);
            }
            catch (TaskCanceledException) { }
            finally
            {
                AlertPopup.IsOpen = false;
            }
        }
    }
    else
    {
        AlertPopup.IsOpen = false;
    }
}

如何解决显示弹出窗口的问题？

1 个答案: