问Wpf -默认按钮未按预期工作

EN

<Window x:Class="WebSiteMon.Results.Views.GraphicSizeSelectPopUp"
        xmlns="http://schemas.microsoft.com/winfx/2006/xaml/presentation"
        xmlns:x="http://schemas.microsoft.com/winfx/2006/xaml"
        xmlns:commonWPF="http://rubenhak.com/common/wpf"
        xmlns:WPF="clr-namespace:Bennedik.Validation.Integration.WPF;assembly=Bennedik.Validation.Integration.WPF"
        ResizeMode="NoResize"
        WindowStyle="ThreeDBorderWindow"
        SizeToContent="WidthAndHeight">
  <Window.Resources>
    <Style TargetType="{x:Type TextBox}">
      <Setter Property="Validation.ErrorTemplate">
        <Setter.Value>
          <ControlTemplate>
            <Border BorderBrush="Red"
                    BorderThickness="2">
              <AdornedElementPlaceholder />
            </Border>
          </ControlTemplate>
        </Setter.Value>
      </Setter>
      <Style.Triggers>
        <Trigger Property="Validation.HasError"
                 Value="true">
          <Setter Property="ToolTip"
                  Value="{Binding RelativeSource={RelativeSource Self}, Path=(Validation.Errors)[0].ErrorContent}" />
        </Trigger>
      </Style.Triggers>
    </Style>
  </Window.Resources>
  <WPF:ErrorProvider x:Name="UrlDataErrorProvider"
                     RulesetName="RuleSetA">
    <Grid Background="{DynamicResource WindowBackgroundBrush}">
      <Grid.ColumnDefinitions>
        <ColumnDefinition Width="25" />
        <ColumnDefinition Width="*" />
        <ColumnDefinition Width="*" />
      </Grid.ColumnDefinitions>
      <Grid.RowDefinitions>
        <RowDefinition Height="*" />
        <RowDefinition Height="*" />
        <RowDefinition Height="*" />
        <RowDefinition Height="*" />
        <RowDefinition Height="*" />
        <RowDefinition Height="*" />
      </Grid.RowDefinitions>

      <RadioButton Grid.ColumnSpan="2"
                   Margin="10"
                   Name="radioButton1"
                   Content="640 x 480 pixels"
                   Command="{Binding SelectSizeRb}"
                   CommandParameter="640,480" />
      <RadioButton Grid.ColumnSpan="2"
                   Margin="10"
                   Name="radioButton2"
                   Content="800 x 600 pixels"
                   Command="{Binding SelectSizeRb}"
                   CommandParameter="800,600"
                   Grid.Row="1"
                   IsChecked="True" />
      <RadioButton Grid.ColumnSpan="2"
                   Margin="10"
                   Name="radioButton3"
                   Content="1024 x 768 pixels"
                   Command="{Binding SelectSizeRb}"
                   CommandParameter="1024,768"
                   Grid.Row="2" />
      <RadioButton Grid.ColumnSpan="2"
                   Margin="10"
                   Name="radioButton4"
                   Command="{Binding SelectSizeRb}"
                   CommandParameter="0,0"
                   Grid.Row="3" />

      <Button Grid.Column="1"
              Grid.ColumnSpan="1"
              Grid.Row="5"
              Margin="5"
              Name="BtnOk"
              IsDefault="True">Ok</Button>
      <Button Grid.Column="2"
              Grid.ColumnSpan="1"
              Grid.Row="5"
              Margin="5"
              Name="BtnCancel"
              IsCancel="True">Cancel</Button>

    </Grid>
  </WPF:ErrorProvider>
</Window>

var p = new GraphicSizeSelectPopUp();
var result = p.ShowDialog() ?? false;
p.Close();