在VM构造函数中为属性赋值时，textbox的WPF数据绑定不会在设计器中显示

public class ViewModel
{
    public string Text { get; set; }

    public ViewModel()
    {
        if (DesignerProperties.GetIsInDesignMode(new DependencyObject()))
        {
            Text = "Design Time Data";
        }
    }
}

<Window ...
        xmlns:d="http://schemas.microsoft.com/expression/blend/2008"
        xmlns:mc="http://schemas.openxmlformats.org/markup-compatibility/2006"
        xmlns:local="clr-namespace:YourNamespace"
        mc:Ignorable="d"
        d:DataContext="{d:DesignInstance local:DesignTimeViewModel, IsDesignTimeCreatable=True}">
    <Window.DataContext>
        <local:ViewModel />
    </Window.DataContext>
    ...
</Window>

public class DesignTimeViewModel
{
    public string Text { get; set; } = "Design Time Data";
}

<TextBox Text="{Binding Text, Mode=OneWay, Source={d:DesignInstance local:DesignTimeViewModel}}" />