C# c WPF将组合框项添加到列表框

我正在尝试这样做，用户可以从组合框中选择一个项目，按下按钮，所选项目将被添加到列表框中。问题是，一旦我做出任何选择并按下按钮，列表框似乎会出现故障，水平滚动滑块会弹出并占据整个空间，我甚至不知道是否添加了该项

XAML代码：

<Label Name="UserEntryLabel" Content="Your chosen entries:" Grid.Row="1" Grid.ColumnSpan="2"  Grid.Column="0" HorizontalAlignment="Right" VerticalAlignment="Bottom" FontSize="15" FontWeight="Bold" Foreground="DarkBlue" Margin="0,0,10,8" Padding="0,0,0,0"/>
<ListBox Name="UserEntryBox" Grid.Row="1" Grid.Column="2" HorizontalAlignment="Left" VerticalAlignment="Bottom" Width="120" Height="20" ScrollViewer.VerticalScrollBarVisibility="Visible" Margin="0,0,0,8"/>
<Label Name="NewEntryLabel" Content="Add new entry:" Grid.Row="2"  Grid.Column="0" HorizontalAlignment="Right" VerticalAlignment="Top" FontSize="15" FontWeight="Bold" Foreground="DarkBlue" Margin="0,8,6,0" Padding="0,0,0,0"/>
<ComboBox Name="NewEntryBox" Grid.Row="2" Grid.Column="1" HorizontalAlignment="Center" VerticalAlignment="Top" Width="120" Height="20" Margin="0,8,0,0">
    <ComboBoxItem IsSelected="True">Entry1</ComboBoxItem>
    <ComboBoxItem>Entry2</ComboBoxItem>
    <ComboBoxItem>Entry3</ComboBoxItem>
    <ComboBoxItem>Entry4</ComboBoxItem>
</ComboBox>
<Button Name="NewEntryButton" Content="Add" Grid.Row="2" Grid.Column="2" HorizontalAlignment="left" VerticalAlignment="Top" Width="90" Height="20" Margin="0,8,0,0" Click="NewChestButtonClick"/>

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您的问题是，您没有在组合框中添加值，而是在整个项目引用中添加值：

System.Windows.Controls.ComboBoxItem:Entry1

如果更改组合框的添加方式，您可以看到它出现在列表框中：

private void AddNewEntry()
{
    UserEntryBox.Items.Add(NewEntryBox.Text);
}

private void AddNewEntry()
{
    UserEntryBox.Items.Add(NewEntryBox.Text);
}