TestWindow.xaml

<Window x:Class="TestWindow"
        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:MyMusicWPF"
        mc:Ignorable="d"
        Title="测试窗体" Height="253.743" Width="363.938" WindowStartupLocation="CenterScreen">
    <Grid>
        <Grid.RowDefinitions>
            <RowDefinition Height="187*"/>
            <RowDefinition Height="40"/>
        </Grid.RowDefinitions>

        <ScrollViewer>
            <TextBox Name="textview">

            </TextBox>
        </ScrollViewer>


        <StackPanel Grid.Row="1" Orientation="Horizontal" >
            <Button Name="btn1" Content="测试1" Click="btn1_Click"  Width="100" Height="30"  />
            <Button Name="btn2" Content="测试2" Click="btn2_Click"  Grid.Row="1" Width="100" Height="30" />
            <Button Name="btn3" Content="测试3" Click="btn3_Click"  Grid.Row="1" Width="100" Height="30" />
        </StackPanel>


    </Grid>
</Window>