Xamarin The property 'Content' is set more than once - xamarin

Question

I have a problem. I want to make a custom header, so I created this stacklayout:
<StackLayout VerticalOptions="Start" HeightRequest="50" HorizontalOptions="CenterAndExpand">
<Image HorizontalOptions="Start" Source="Logo.png"/>
<Image HorizontalOptions="Start" Source="Title_Dark.png"/>
</StackLayout>
Now I want to put it above the following code:
<ContentPage.Content>
<ListView x:Name="ListViewMain" VerticalOptions="FillAndExpand" BackgroundColor="#212121" SelectionMode="None">
<ListView.ItemTemplate>
<DataTemplate>
<ViewCell>
<StackLayout>
<Label HeightRequest="1" BackgroundColor="#E3E3E3" />
<Grid x:Name="GridMain">
<Grid.RowDefinitions>
<RowDefinition Height="40" x:Name="Row0_Height"/>
<RowDefinition Height="180" x:Name="Row1_Height"/>
<RowDefinition Height="180" x:Name="Row2_Height"/>
<RowDefinition Height="40" x:Name="Row3_Height"/>
</Grid.RowDefinitions>
<Grid.ColumnDefinitions>
<ColumnDefinition Width="40" x:Name="Column0_Width" />
<ColumnDefinition Width="*" x:Name="Column1_Width" />
<ColumnDefinition Width="40" x:Name="Column2_Width" />
</Grid.ColumnDefinitions>
<Label Text="{Binding Creator}" TextColor="White" FontSize="Body" FontAttributes="Bold" Grid.Column="1" Grid.Row="0" VerticalOptions="Center" HorizontalOptions="Start"/>
<Image Source="VoteUp.png" VerticalOptions="End" HorizontalOptions="Center" Grid.Row="1" Grid.Column="0">
<Image.GestureRecognizers>
<TapGestureRecognizer Tapped="imgVoteUp_Clicked" />
</Image.GestureRecognizers>
</Image>
<Image Source="VoteDown.png" VerticalOptions="Start" HorizontalOptions="Center" Grid.Row="2" Grid.Column="0">
<Image.GestureRecognizers>
<TapGestureRecognizer Tapped="imgVoteDown_Clicked" />
</Image.GestureRecognizers>
</Image>
<Image Source="{Binding ImageLocation}" Margin="0, 0, 20, 0" Grid.Column="1" Grid.ColumnSpan="2" Grid.Row="1" Grid.RowSpan="2" BackgroundColor="AliceBlue" VerticalOptions="Fill" HorizontalOptions="Fill"/>
<Image Source="Favorite.png" Grid.Row="3" Grid.Column="1" HorizontalOptions="Start">
<Image.GestureRecognizers>
<TapGestureRecognizer Tapped="imgFavorite_Clicked" />
</Image.GestureRecognizers>
</Image>
<Image Source="Send_Dark.png" Grid.Row="3" Grid.Column="1" HorizontalOptions="End"/>
<Image Source="Save_Dark.png" Grid.Row="3" Grid.Column="2" HorizontalOptions="End"/>
</Grid>
</StackLayout>
</ViewCell>
</DataTemplate>
</ListView.ItemTemplate>
</ListView>
</ContentPage.Content>
But when I put it right under the <ContentPage.Content> tag, it gives the following error:
The property 'Content' is set more than once
When I put it above the <ContentPage.Content> tag, my whole screen is the header.
How can I fix this?

Answer 1

Content can only have ONE child element. If you want to have multiple child elements, you need to place them inside of a layout container (Grid, StackLayout, etc)