Use base class control in Mainwindow XAML - wpf

Question

I wan to create a base class which consits properties of both User contorl and window and that baseclass control used in my Mainwindow.xaml.
Below code i am using but getting following error "Partial declarations of 'MainWindow' must not specify different base classes"
Usercontrol1.xaml
<UserControl x:Class="WpfApplication1.UserControl1"
xmlns="http://schemas.microsoft.com/winfx/2006/xaml/presentation"
xmlns:x="http://schemas.microsoft.com/winfx/2006/xaml"
xmlns:mc="http://schemas.openxmlformats.org/markup-compatibility/2006"
xmlns:d="http://schemas.microsoft.com/expression/blend/2008"
xmlns:local="clr-namespace:WpfApplication1"
mc:Ignorable="d"
d:DesignHeight="300" d:DesignWidth="300">
<Grid>
<TextBox x:Name="textBox" HorizontalAlignment="Left" Height="23" Margin="80,46,0,0" TextWrapping="Wrap" Text="TextBox" VerticalAlignment="Top" Width="120"/>
<Button x:Name="button" Content="Button" HorizontalAlignment="Left" Margin="80,82,0,0" VerticalAlignment="Top" Width="75" Click="button_Click"/>
</Grid>
</UserControl>
UserControl1.xaml.cs
namespace WpfApplication1
{
public class baseclass : UserControl
{
public Button textBox { get; set; }
public baseclass()
{
}
private void button_Click(object sender, RoutedEventArgs e)
{
if (!string.IsNullOrEmpty(textBox.ToString()))
{
}
}
}
public partial class UserControl1
{
public UserControl1()
{
InitializeComponent();
}
}
}
Now Problem is that how can i use usecontrol in my Main window.code for main window below
Mainwindow.xaml.cs
namespace WpfApplication1
{
/// <summary>
/// Interaction logic for MainWindow.xaml
/// </summary>
public partial class MainWindow : Window
{
public MainWindow()
{
InitializeComponent();
}
}
}
MainWindow.xaml
<Window x:Class="WpfApplication1.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:WpfApplication1"
mc:Ignorable="d"
Title="MainWindow" Height="350" Width="525">
<Grid>
</Grid>
</Window>

Answer 1

I'm not sure if I'm missing something obvious or others have missed something obvious! I can add baseclass to MainWindow just fine with:
<Window x:Class="WpfApp2.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:WpfApp2"
mc:Ignorable="d"
Title="MainWindow" Height="350" Width="525">
<local:baseclass />
</Window>
The key thing is local: xmlns namespace that's defined as xmlns:local="clr-namespace:WpfApp2"
If you're not merely cargo culting the code, you can see how the above will work for you.
Now the real answer for the question you didn't ask: you're doing this wrong! The textbox in baseclass will never work because you haven't initialised it as a UserControl (there's more to this than just inheriting from UserControl) Learn MvvM and stop relying on code behind. Your life will get much easier.

Answer 2

i want to use base user control in main window this is what i ma trying to do
You can't. A top-level window class cannot inherit from System.Windows.Controls.UserControl. It must inherit from a System.Windows.Window. So it is not possible to define a common base class for both user controls and windows in WPF.
You can change the base class of UserControl1 though but you must specify the same base class in both the XAML markup and the code-behind file:
UserControl1.xaml.cs:
public partial class UserControl1 : baseclass
{
public UserControl1()
{
InitializeComponent();
}
}
UserControl1.xaml:
<local:baseclass x:Class="WpfApplication1.UserControl1"
xmlns="http://schemas.microsoft.com/winfx/2006/xaml/presentation"
xmlns:x="http://schemas.microsoft.com/winfx/2006/xaml"
xmlns:mc="http://schemas.openxmlformats.org/markup-compatibility/2006"
xmlns:d="http://schemas.microsoft.com/expression/blend/2008"
xmlns:local="clr-namespace:WpfApplication1"
mc:Ignorable="d"
d:DesignHeight="300" d:DesignWidth="300">
<Grid>
<TextBox x:Name="textBox" HorizontalAlignment="Left" Height="23" Margin="80,46,0,0" TextWrapping="Wrap" Text="TextBox" VerticalAlignment="Top" Width="120"/>
<Button x:Name="button" Content="Button" HorizontalAlignment="Left" Margin="80,82,0,0" VerticalAlignment="Top" Width="75" Click="button_Click"/>
</Grid>
</local:baseclass>