Why my xaml only shows a plain window show up with nothig in it

问题

I am new to WPF, Xaml, and am a C# beginner! I have been working on this and I don't know why the following xaml just shows a plain window. No button, no title, no content. I would appreciate your guidance. If asking why I had to use MediaChecker I did it following an example from Stack Overflow's following post:

How do i navigate from one Xaml file to another?

Thanks in advance.

<Window x:Class="MediaCheckerWPF.AboutBox" 
    xmlns="http://schemas.microsoft.com/winfx/2006/xaml/presentation" 
    xmlns:x="http://schemas.microsoft.com/winfx/2006/xaml" 
    Title="About Media Checker" Height="300" Width="400" ResizeMode="NoResize" 
    ShowInTaskbar="False">
    <Grid>
        <Grid.RowDefinitions>
            <RowDefinition Height="Auto" />
            <RowDefinition Height="Auto" />
            <RowDefinition Height="*" />
            <RowDefinition Height="28" />
        </Grid.RowDefinitions>
        <Grid.ColumnDefinitions>
            <ColumnDefinition Width="Auto" />
            <ColumnDefinition Width="200" />
        </Grid.ColumnDefinitions>
        <Label Grid.Row="0" Grid.Column="0" Content="Name:"/>
        <Label Grid.Row="1" Grid.Column="0" Content="E-Mail:"/>
        <Label Grid.Row="2" Grid.Column="0" Content="Comment:"/>
        <Button Grid.Column="1" Grid.Row="0" HorizontalAlignment="Right" 
            MinWidth="80" Margin="3" Content="START"  />
        <Button Grid.Column="1" Grid.Row="3" HorizontalAlignment="Right" 
            MinWidth="80" Margin="3" Content="STOP"  />

    </Grid>
</Window> 

回答1:

The XAML you have renders just fine. If you're getting a blank window then I suspect it has to do with something else, such as starting up a different Window.

Double-check that the correct Window is starting up in the StartupUri property of your <Application> tag in App.xaml

<Application x:Class="MediaCheckerWPF.App"
             xmlns="http://schemas.microsoft.com/winfx/2006/xaml/presentation"
             xmlns:x="http://schemas.microsoft.com/winfx/2006/xaml"
             StartupUri="AboutBox.xaml">
    <Application.Resources>

    </Application.Resources>
</Application>

回答2:

Check the App.xaml for the StartupUri

<Application x:Class="GabeTexFilestImport.App"
             xmlns="http://schemas.microsoft.com/winfx/2006/xaml/presentation"
             xmlns:x="http://schemas.microsoft.com/winfx/2006/xaml"
             StartupUri="MainWindow.xaml">
    <Application.Resources>

    </Application.Resources>
</Application>

回答3:

I have noticed this happening also if system is very slow. Say, you are reaching max memory consumption which slows down your system. In that case, I have seen xaml windows showing up but completelly blank, no controls on it, no min, max, close buttons, no title.

来源：https://stackoverflow.com/questions/12148097/why-my-xaml-only-shows-a-plain-window-show-up-with-nothig-in-it