Now that's a real strange error. I am working on a WPF application and following MVVM. In my MainWindow I am setting views and view models and I get this strange error. Although it builds fine and application runs fine, but why I am getting this error.

I also followed some similar but didn't find appropriate answer. I tried to restart visual studio and clean and rebuild, but still I face this error.

So here is the code.

```
<Window x:Class="MyProject.MainWindow"
        xmlns="http://schemas.microsoft.com/winfx/2006/xaml/presentation"
        xmlns:x="http://schemas.microsoft.com/winfx/2006/xaml"
        xmlns:v="clr-namespace:MyProject.Views"
        xmlns:vm="clr-namespace:MyProject.ViewModels"
        xmlns:p="clr-namespace:MyProject.Properties"
        Title="{x:Static p:Resources.Title}" Height="400" Width="750" MinHeight="400" MinWidth="750">
    <Window.Resources>
        <DataTemplate DataType="{x:Type vm:MainPageViewModel}">
            <v:MainPageView/>
        </DataTemplate>
    </Window.Resources>

Error   1   The name "MainPageViewModel" does not exist in the namespace "clr-namespace:MyProject.ViewModels".

```

Here is my ViewModel

```
namespace MyProject.ViewModels
{
    public class MainPageViewModel : PropertyChangedBase
    {
        public MainPageViewModel()
        {
        }
    }
}

```

So what is real error. I am using Visual Studio 2012 by the way.

**Update:**
My viewmodels and views are in the same project. I am not referencing to any other project. And MyProject.ViewModels.MainPageViewModel exists.