XamlParseException in View

Question

I've got a view that shows only a Label.

The viewmodel is injected correctly in the view because the text of the label is bound to a viewmodel property. Now, if I try to define a DataGrid in the xaml, I've got a XamlParseException:

{System.Windows.Markup.XamlParseException: Type 'DataGrid' not found. [Line: 16 Position: 45] su System.Windows.Application.LoadComponent(Object component, Uri resourceLocator) su Common.Views.FunctionalityView.InitializeComponent() su Common.Views.FunctionalityView..ctor(IFunctionalityViewModel viewModel)}

BUT if I define a DataGrid myDg = new DataGrid() right before the InitializeComponent(); it works.

I've checked all references and still can't find the problem.

Philo

Could you edit to add the actual text of the exception? Your paraphrase makes it hard to understand what is going on. Also, check for any inner exceptions as well. – Filbert

The exception occurs in FunctionalityView constructor, InitializeComponent(). – Philo

K, your default namespace has been messed up. Create a new UserControl and look at all the xmlns definitions in the UserControl. Compare them with the ones in your View. Fix as needed. – Filbert

If that was the issue, I have added an answer which explains it better. – Filbert

Answer 1

It sounds like your default namespace is messed up or missing. Without the xaml, it is hard to tell what you should do.

An easy way to figure this out for yourself is to create a new UserControl, then examine and compare the xmlns namespaces defined on its root with the root element of your View.

WPF locates types by a specialized namespace definition. It follows the format

clr-namespace:[namespace](;assembly=[assembly name])

where

[namespace]

is the namespace that contains the type definition. And, if the type is defined within a different assembly from the one where the xaml file is located, you have to include the part within the preface. [assembly name] is the name of the assembly without the .dll extension (e.g., assembly=mscorlib would import mscorlib.dll). To import the Int32 type and use it within your xaml, you'll have to define the namespace

xmlns:s="clr-namespace:System;assembly=mscorlib"

There also exists an assembly-level attribute which allows you to assign a different namespace for all types within an assembly. Typically, this takes the form of a URL. This is by tradition rather than necessity, IIRC. This is why some controls are identified with a more traditional namespace, such as

xmlns="http://schemas.microsoft.com/winfx/2006/xaml/presentation"

Filbert

Thank you, i've checked my xmlns:sdk="http://schemas.microsoft.com/winfx/2006/xaml/presentation/sdk" xmlns="http://schemas.microsoft.com/winfx/2006/xaml/presentation" and now it works – Philo