自定义WPF MessageBox文本为空

时间：2016-07-11 12:44:45

标签： c# wpf

我有一个自定义WPF MessageBox，在特定邮件标题出现在父窗口的随机位置时。自定义MessageBox如下所示：

public static class WPFMessageBox
{
    public static MessageBoxResult Show(string messageBoxText)
    {
        return ShowCore(null, messageBoxText);
    }

    public static MessageBoxResult Show(string messageBoxText, string caption)
    {
        return ShowCore(null, messageBoxText, caption);
    }

    public static MessageBoxResult Show(Window owner, string messageBoxText)
    {
        return ShowCore(owner, messageBoxText);
    }

    public static MessageBoxResult Show(string messageBoxText, string caption, MessageBoxButton button)
    {
        return ShowCore(null, messageBoxText, caption, button);
    }

    public static MessageBoxResult Show(Window owner, string messageBoxText, string caption)
    {
        return ShowCore(owner, messageBoxText, caption);
    }

    public static MessageBoxResult Show(string messageBoxText, string caption, MessageBoxButton button, MessageBoxImage icon)
    {
        return ShowCore(null, messageBoxText, caption, button, icon);
    }

    public static MessageBoxResult Show(Window owner, string messageBoxText, string caption, MessageBoxButton button)
    {
        return ShowCore(owner, messageBoxText, caption, button);
    }

    public static MessageBoxResult Show(string messageBoxText, string caption, MessageBoxButton button, MessageBoxImage icon, MessageBoxResult defaultResult)
    {
        return ShowCore(null, messageBoxText, caption, button, icon, defaultResult);
    }

    public static MessageBoxResult Show(Window owner, string messageBoxText, string caption, MessageBoxButton button, MessageBoxImage icon)
    {
        return ShowCore(owner, messageBoxText, caption, button, icon);
    }

    public static MessageBoxResult Show(string messageBoxText, string caption, MessageBoxButton button, MessageBoxImage icon, MessageBoxResult defaultResult, MessageBoxOptions options)
    {
        return ShowCore(null, messageBoxText, caption, button, icon, defaultResult, options);
    }

    public static MessageBoxResult Show(Window owner, string messageBoxText, string caption, MessageBoxButton button, MessageBoxImage icon, MessageBoxResult defaultResult)
    {
        return ShowCore(owner, messageBoxText, caption, button, icon, defaultResult);
    }

    public static MessageBoxResult Show(Window owner, string messageBoxText, string caption, MessageBoxButton button, MessageBoxImage icon, MessageBoxResult defaultResult, MessageBoxOptions options)
    {
        return ShowCore(owner, messageBoxText, caption, button, icon, defaultResult, options);
    }

    private static MessageBoxResult ShowCore(
        Window owner,
        string messageBoxText,
        string caption = "",
        MessageBoxButton button = MessageBoxButton.OK,
        MessageBoxImage icon = MessageBoxImage.None,
        MessageBoxResult defaultResult = MessageBoxResult.None,
        MessageBoxOptions options = MessageBoxOptions.None)
    {
        if (caption == "specific message caption")
        {
            var maxHeight = owner.ActualHeight - 300;
            var maxWidth = owner.ActualWidth - 500;
            var randomHeight = GetRandomNumber(2, maxHeight);
            var randomWidth = GetRandomNumber(2, maxWidth);

            return WPFMessageBoxWindow.Show(
                delegate(Window messageBoxWindow)
                {
                    messageBoxWindow.WindowStartupLocation = WindowStartupLocation.Manual;
                    messageBoxWindow.Left = randomWidth;
                    messageBoxWindow.Top = randomHeight;
                    messageBoxWindow.Owner = owner;
                },
                messageBoxText, caption, button, icon, defaultResult, options);
        }

        return WPFMessageBoxWindow.Show(
            delegate(Window messageBoxWindow)
            {
                messageBoxWindow.Owner = owner;
            },
            messageBoxText, caption, button, icon, defaultResult, options);
    }

    private static double GetRandomNumber(double minimum, double maximum)
    {
        Random random = new Random();
        return random.NextDouble() * (maximum - minimum) + minimum;
    }
}

WPF MessageBox窗口如下所示：

public partial class WPFMessageBoxWindow : Window
{
    public WPFMessageBoxWindow()
    {
        InitializeComponent();
    }

    private MessageBoxViewModel _viewModel;

    public static MessageBoxResult Show(
        Action<Window> setOwner,
        string messageBoxText, 
        string caption, 
        MessageBoxButton button, 
        MessageBoxImage icon, 
        MessageBoxResult defaultResult, 
        MessageBoxOptions options)
    {
        if ((options & MessageBoxOptions.DefaultDesktopOnly) == MessageBoxOptions.DefaultDesktopOnly)
        {
            throw new NotImplementedException();
        }

        if ((options & MessageBoxOptions.ServiceNotification) == MessageBoxOptions.ServiceNotification)
        {
            throw new NotImplementedException();
        }

        _messageBoxWindow = new WPFMessageBoxWindow()
        {
            ShowInTaskbar = false,
            Topmost = true,
            ResizeMode = ResizeMode.NoResize
        };

        setOwner(_messageBoxWindow);

        PlayMessageBeep(icon);

        _messageBoxWindow._viewModel = new MessageBoxViewModel(_messageBoxWindow, caption, messageBoxText, button, icon, defaultResult, options);
        _messageBoxWindow.DataContext = _messageBoxWindow._viewModel;
        _messageBoxWindow.ShowDialog();
        return _messageBoxWindow._viewModel.Result;
    }

    private static void PlayMessageBeep(MessageBoxImage icon)
    {
        switch (icon)
        {
            //case MessageBoxImage.Hand:
            //case MessageBoxImage.Stop:
            case MessageBoxImage.Error:
                SystemSounds.Hand.Play();
                break;

            //case MessageBoxImage.Exclamation:
            case MessageBoxImage.Warning:
                SystemSounds.Exclamation.Play();
                break;

            case MessageBoxImage.Question:
                SystemSounds.Question.Play();
                break;

            //case MessageBoxImage.Asterisk:
            case MessageBoxImage.Information:
                SystemSounds.Asterisk.Play();
                break;

            default:
                SystemSounds.Beep.Play();
                break;
        }
    }

    [ThreadStatic]
    private static WPFMessageBoxWindow _messageBoxWindow;

    protected override void OnSourceInitialized(EventArgs e)
    {
        // removes the application icon from the window top left corner
        // this is different than just hiding it
        WindowHelper.RemoveIcon(this);

        switch (_viewModel.Options)
        { 
            case MessageBoxOptions.None:
                break;

            case MessageBoxOptions.RightAlign:
                WindowHelper.SetRightAligned(this);
                break;

            case MessageBoxOptions.RtlReading:
                break;

            case MessageBoxOptions.RightAlign | MessageBoxOptions.RtlReading:
                break;
        }

        // disable close button if needed and remove resize menu items from the window system menu
        var systemMenuHelper = new SystemMenuHelper(this);

        if (_viewModel.ButtonOption == MessageBoxButton.YesNo)
        {
            systemMenuHelper.DisableCloseButton = true;
        }

        systemMenuHelper.RemoveResizeMenu = true;
    }

    private void Window_KeyDown(object sender, KeyEventArgs e)
    {
        if (e.Key == Key.Escape)
        {
            _viewModel.EscapeCommand.Execute(null);
        }
    }

    protected override void OnClosed(EventArgs e)
    {
        base.OnClosed(e);
        _viewModel.CloseCommand.Execute(null);
    }
}

这是我如何在代码中使用MessageBox作为我的特定标题：

dynamic parentWindow = Window.GetWindow(this);
var result = WPFMessageBox.Show(parentWindow, "message text", "specific message cation", 
MessageBoxButton.YesNo, MessageBoxImage.Question);

我的问题是，偶尔只有这个特定的消息，MessageBox文字显示为空：

empty text

这是XAML：

<Window
    xmlns="http://schemas.microsoft.com/winfx/2006/xaml/presentation"
    xmlns:x="http://schemas.microsoft.com/winfx/2006/xaml"
    xmlns:local="clr-namespace:MessageBoxUtils"
    xmlns:d="http://schemas.microsoft.com/expression/blend/2008" xmlns:mc="http://schemas.openxmlformats.org/markup-compatibility/2006" mc:Ignorable="d" x:Class="MessageBoxUtils.WPFMessageBoxWindow"
    Title="{Binding Title}" ResizeMode="NoResize" FlowDirection="{Binding TitleFlowDirection}"
    ShowInTaskbar="False" WindowStartupLocation="CenterScreen" SizeToContent="Height" KeyDown="Window_KeyDown" Width="500" d:DesignWidth="500" Height="300">
<Grid>

    <Grid FlowDirection="{Binding ContentFlowDirection}">
        <Grid.RowDefinitions>
            <RowDefinition Height="60" />
            <RowDefinition Height="2" />
            <RowDefinition Height="*" />
            <RowDefinition Height="90" />
        </Grid.RowDefinitions>
        <Grid.ColumnDefinitions>
            <ColumnDefinition Width="60" />
            <ColumnDefinition Width="*" />
        </Grid.ColumnDefinitions>

        <Image Source="{Binding MessageImageSource}" HorizontalAlignment="Left" VerticalAlignment="Center" Height="32" Width="32" Margin="10 0 0 0" />

        <TextBlock FontSize="28" Text="{Binding Message}" Grid.RowSpan="3" Grid.Column="1" TextWrapping="Wrap" TextAlignment="Left" HorizontalAlignment="{Binding ContentTextAlignment}" VerticalAlignment="Top" Margin="10,10,10,0"  />

        <Border Grid.Row="3" Grid.Column="0" Grid.ColumnSpan="2" Background="#FFE6E6E6" BorderThickness="0 1 0 0" BorderBrush="#FFDFDFDF">
            <StackPanel Orientation="Horizontal" VerticalAlignment="Center" HorizontalAlignment="Right" Margin="0,18,10,10" Height="63" >
                <Button FontSize="25" Content="_Yes" Visibility="{Binding YesNoVisibility}" Command="{Binding YesCommand}" IsDefault="{Binding IsYesDefault}" Margin="5 5 5 5" Height="42" Width="80" />
                <Button FontSize="25" Content="_No" Visibility="{Binding YesNoVisibility}" Command="{Binding NoCommand}" IsDefault="{Binding IsNoDefault}" Margin="5 5 5 5" Height="42" Width="80" />
                <Button FontSize="25" Content="O_K" Visibility="{Binding OkVisibility}" Command="{Binding OkCommand}" IsDefault="{Binding IsOkDefault}" Margin="5 5 5 5" Height="42" Width="80" />
                <Button FontSize="25" Content="_Cancel" Visibility="{Binding CancelVisibility}" Command="{Binding CancelCommand}" IsDefault="{Binding IsCancelDefault}" Margin="5 5 5 5" Height="42" Width="80" />
            </StackPanel>
        </Border>
    </Grid>


</Grid>

有谁知道为什么？

1 个答案:

答案 0 :(得分：0)

您将文本绑定到名为＆＃39;消息＆＃39;但是我没有在你的虚拟机中看到它......除非我错过了它！

无论如何，我的赌注是你在更新该属性时没有发出NotifyPropertyChanged事件，所以如果在视图之前创建了viewmodel，那么视图会查询VM并且一切都很好，但是如果VM是在视图之后填充一点，然后视图将在查询时收到空字符串。然后在VM中更新该属性，但视图永远不会被告知。只是预感。

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