如何在WPF窗口添加多个控件？新手遇控件被删除异常

First off: you absolutely don't need to create separate XAML files for each control—that's not how WPF works, and this problem is definitely an abnormal quirk we can sort out.

Let's break down what's happening and how to fix it:

The root cause: Missing a container control in your Window #

WPF Windows can only have one direct child element. Right now, your Window's only direct child is the <Image> tag. When you drag a new Label (or any control) into the designer, it's defaulting to replacing that single child element instead of adding to it—hence your Image getting deleted every time.

This is a super common beginner pitfall, and the fix is simple: add a panel control (like Grid, StackPanel, or DockPanel) as the Window's direct child, then put all your controls inside that panel.

Step 1: Update your XAML with a root Grid #

Here's your modified XAML with a Grid added as the container—this will let the designer add new controls without replacing existing ones:

<Window x:Class="Lively.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:Lively" 
        mc:Ignorable="d" 
        Title="Lively" Height="450" Width="662" Foreground="Black" 
        AllowsTransparency="True" WindowStyle="None" ResizeMode="CanMinimize" 
        WindowStartupLocation="CenterScreen" Cursor="Arrow" MouseDown="DragWindow">
    <Window.Background>
        <LinearGradientBrush EndPoint="0.5,1" StartPoint="0.5,0">
            <LinearGradientBrush.RelativeTransform>
                <TransformGroup>
                    <ScaleTransform CenterY="0.5" CenterX="0.5" ScaleY="2"/>
                    <SkewTransform CenterY="0.5" CenterX="0.5"/>
                    <RotateTransform Angle="40.601" CenterY="0.5" CenterX="0.5"/>
                    <TranslateTransform/>
                </TransformGroup>
            </LinearGradientBrush.RelativeTransform>
            <GradientStop Color="Black" Offset="0.033"/>
            <GradientStop Color="#FF360606" Offset="1"/>
            <GradientStop Color="#FF0F0202"/>
            <GradientStop Color="#FF0D0101" Offset="0.248"/>
            <GradientStop Color="#FE170202"/>
            <GradientStop Color="#FF0B0101" Offset="0.211"/>
            <GradientStop Color="#FF080808" Offset="0.256"/>
            <GradientStop Color="#FF2E0606" Offset="1"/>
            <GradientStop Color="#FF0E0707" Offset="1"/>
            <GradientStop Color="#FF010000" Offset="0.274"/>
        </LinearGradientBrush>
    </Window.Background>
    <Window.OpacityMask>
        <LinearGradientBrush EndPoint="0.5,1" StartPoint="0.5,0">
            <GradientStop Color="Black" Offset="0.207"/>
            <GradientStop Color="Black" Offset="0.007"/>
        </LinearGradientBrush>
    </Window.OpacityMask>

    <!-- This Grid is your new root container -->
    <Grid>
        <Image x:Name="Logo" Source="src/Assets/Core/Lively_32x32.png" HorizontalAlignment="Left" Height="39" Margin="619,10,0,0" VerticalAlignment="Top" Width="33" RenderTransformOrigin="0.467,0.5" Stretch="None" ToolTip="Just the logo :)"/>
        <!-- Now you can drag Label/Button/etc. here without losing existing controls -->
    </Grid>
</Window>

After making this change, try dragging a Label into the designer again—it should add it to the Grid alongside your Image instead of replacing it.

If that doesn't work: Fix Visual Studio Designer cache #

Sometimes the WPF Designer gets glitchy due to corrupted cache. Try these steps:

• Close Visual Studio entirely
• Delete the hidden .vs folder in your project's root directory
• Reopen your project, then go to Build → Clean Solution followed by Build → Rebuild Solution
• In the designer window, click the "Reload Designer" button (top-right corner)

Quick check: Ensure no XAML syntax errors #

Double-check that your XAML has no unclosed tags or typos—while your current code looks fine, even a small syntax issue can throw off the designer.

内容的提问来源于stack exchange，提问作者wellinthatcase