BPASmartClient/WpfTest/MainWindow.xaml

<Window x:Class="WpfTest.MainWindow"
        xmlns="http://schemas.microsoft.com/winfx/2006/xaml/presentation"
        xmlns:x="http://schemas.microsoft.com/winfx/2006/xaml"
        xmlns:d="http://schemas.microsoft.com/expression/blend/2008"
        xmlns:mc="http://schemas.openxmlformats.org/markup-compatibility/2006"
        xmlns:local="clr-namespace:WpfTest"
        mc:Ignorable="d"
        Title="MainWindow" Height="450" Width="800">
    <Grid>
        <TextBox x:Name="textwb" Background="Black" Foreground="#FFC000FB" TextWrapping="Wrap" AcceptsReturn="True" ></TextBox>
        <Button Width="100" Height="100" Click="Button_Click" Visibility="Collapsed"></Button>
    </Grid>
</Window>