We Keep Coding

Why can't a custom ListView have it's own xaml file?

Why can't my custom ListView have it's own xaml file? I have a custom Button and it works with a xaml file with no issues, but not my ListView. The main reason I want to use this approach (rather than be forced to create a Style that is place in the Generic.xaml file) is because I would like to take advantage of the Resources element and place all resources related to the listview within the xaml file:
public sealed partial class MyListView : ListView
{
public MyListView()
{
this.InitializeComponent();
}
}
And here is the associated xaml file:
<ListView
x:Class="App1.MyListView"
xmlns="http://schemas.microsoft.com/winfx/2006/xaml/presentation"
xmlns:x="http://schemas.microsoft.com/winfx/2006/xaml"
xmlns:local="using:App1"
xmlns:d="http://schemas.microsoft.com/expression/blend/2008"
xmlns:mc="http://schemas.openxmlformats.org/markup-compatibility/2006"
mc:Ignorable="d"
d:DesignHeight="300"
d:DesignWidth="400">
<ListView.Resources>
<!-- I would like to place all related resources here instead of having
them placed in external locations, and then have to open different files to find them. -->
</ListView.Resources>
</ListView>

Although I would expect this should work as well, it seems that this problem is present and it is recommended to use the templated control instead.
I suppose the problem is that assigning the compiler is unable to generate the valid assignment to the Items property of the control, which it is trying to construct from the content of the element. Even when the element is closed immediately it seems to be an issue.

Why not place resources on the Page or inside ListView, rather than deriving your own control?
<Page
x:Class="ListViewResources.MainPage"
xmlns="http://schemas.microsoft.com/winfx/2006/xaml/presentation"
xmlns:x="http://schemas.microsoft.com/winfx/2006/xaml"
xmlns:local="using:ListViewResources"
xmlns:d="http://schemas.microsoft.com/expression/blend/2008"
xmlns:mc="http://schemas.openxmlformats.org/markup-compatibility/2006"
mc:Ignorable="d">
<Page.Resources>
<!-- Place all related resources here instead of having them placed in external locations, and then have to open different files to find them. -->
</Page.Resources>
<ListView x:Name="MyListView">
<ListView.Resources>
<!-- Or place related resources here -->
</ListView.Resources>
</ListView>
</Page>

How to use view models for windows inside a DLL

I'm new to WPF. Here is xaml defining a window defined inside a DLL:
<Window x:Class="MyNamespace.MyClass"
xmlns="http://schemas.microsoft.com/winfx/2006/xaml/presentation"
xmlns:x="http://schemas.microsoft.com/winfx/2006/xaml"
xmlns:d1p1="http://schemas.openxmlformats.org/markup-compatibility/2006"
xmlns:d="http://schemas.microsoft.com/expression/blend/2008"
d1p1:Ignorable="d"
xmlns:attachedProperties="clr-namespace:MyNamespace.AttachedProperties"
xmlns:viewModels="clr-namespace:MyNamespace.ViewModels"
DataContext="{Binding Source={StaticResource VmLocator}}"
Title="{Binding MyVm.MyTitle, Mode=OneTime}" Height="300" Width="460">
<Window.Resources>
<viewModels:ViewModelLocatorTestSteps x:Key="VmLocator" d:IsDataSource="True" />
</Window.Resources>
When the client code constructs this window object, this exception is thrown:
Cannot find resource named 'VmLocator'
How do I define the resource earlier so that it exists when it is needed? I'd also prefer the solution enable Intellisense to work. This is my first attempt at a window defined inside a DLL.
Using Visual Studio 2013.

If you want the Window to create its own DataContext, you can just stick that in the constructor in the code-behind, and avoid the necessity of making your VmLocator a resource. The resources of a WPF control (including a Window) are available to children of that control.
just:
public MyNamespace()
{
InitializeComponents();
this.DataContext = new VmLocator();
}
If you really want to make your DataContext a resource, you could create an application-level resource and reference that.
Also - 'MyNamespace' is a very confusing name for a class :)

How could I access wpf window resoures

I have this xaml
<mui:ModernWindow x:Uid="mui:ModernWindow_1" x:Class="App1.HomePage"
xmlns="http://schemas.microsoft.com/winfx/2006/xaml/presentation"
xmlns:x="http://schemas.microsoft.com/winfx/2006/xaml"
xmlns:mui="http://firstfloorsoftware.com/ModernUI"
xmlns:sys="clr-namespace:System;assembly=mscorlib"
ContentSource="/Window1.xaml"
Title="MainWindow" Height="350" Width="525" WindowState="Maximized" MenuLinkGroups="{Binding menuLinkGroups}">
<mui:ModernWindow.Resources>
<sys:String x:Key="ApplicationName">Bla Bla</sys:String>
</mui:ModernWindow.Resources>
<Grid Style="{StaticResource ContentRoot}" Name="mainGrid">
</Grid>
</mui:ModernWindow>
I need to reference current window resources, so I used this:
object obj = this.Resources["ApplicationName"];
But this.Resources doesn't have any resource! so obj is always null. How could I reference this window resources?

Assume that this is a FrameworkElement, like a Window, a Grid, a Button or something like that.
object obj = this.TryFindResource("ApplicationName");

Assuming this is a control...
var parent = Window.GetWindow(this)
Will get the window the control is currently on, you should then be able to access the resources like you already did
parent.Resources["ApplicationName"];

you can use below mentioned code
var MainGrid=Application.Current.FindResource("strApp")
or
this.FindResource("ApplicationName")

Thanks all, I find the solution (I forget to update the localized dll).
I cleaned and rebuilt solution, used locbaml.exe again to generate new localized dll.

You should bind in the XAML and not in the code behind.
"res" is the namespace where the resources file is located.
In your example the namespace alias is "local":
xmlns:local="clr-namespace:Project.Resources"
So your code should look like:
<Page Title ="{x:Static local:localStrings.step1Description}" />
Where:
"local" is the namespace alias where the resources file is located.
"localStrings" is the name of the resource file.
"step1Description" is an entry in the resource file.

How to implement converter class in usercontrol

I want to make a converter class , I implemented it and i want to use it in another xaml class
So i write this code
<UserControl
xmlns="http://schemas.microsoft.com/winfx/2006/xaml/presentation"
xmlns:x="http://schemas.microsoft.com/winfx/2006/xaml"
xmlns:local="using:PoliceApp"
xmlns:common="using:PoliceApp.Common"
xmlns:d="http://schemas.microsoft.com/expression/blend/2008"
xmlns:mc="http://schemas.openxmlformats.org/markup-compatibility/2006"
mc:Ignorable="d">
<UserControl.Resources>
<local:TitleToImgConverter x:Key="BoolOrConverter"/>
</UserControl.Resources>
</UserControl>
It tells me that there is a missing attribute for user control
and my first code was
DataContext="{Binding DefaultViewModel, RelativeSource={RelativeSource Self}}"
xmlns="http://schemas.microsoft.com/winfx/2006/xaml/presentation"
xmlns:x="http://schemas.microsoft.com/winfx/2006/xaml"
xmlns:local="using:PoliceApp"
xmlns:common="using:PoliceApp.Common"
xmlns:d="http://schemas.microsoft.com/expression/blend/2008"
xmlns:mc="http://schemas.openxmlformats.org/markup-compatibility/2006"
mc:Ignorable="d">
<UserControl.Resources>
<local:TitleToImgConverter x:Key="BoolOrConverter"/>
</UserControl.Resources>
And the error was "The name titletoimgconverter doesnt exist in the namespace using:policeApp"

This is normal (at least, I have never seen it otherwise) when you have just created a new converter and added it as a resource in your XAML code. XAML code often lags behind when something is added to the namespace.
The solution for this is to rebuild your entire project. The XAML should now be able to locate your converter, and the error should disappear.
Update
If your converter exists in some folder called Converter, you should use your first example, and replace xmlns:local="using:PoliceApp" with xmlns:local="clr-namespace:PoliceApp.Converter". If it just resides in your main folder, you can leave out the .Converter. Note that I've replaced the using: with clr-namespace:.

How to define UserControl with custom content?

I want to define my custom decorator that has user content in it. But it always fail when I try to set some control's name. I always get this exception when trying to do it:
Cannot set Name attribute value 'butt' on element 'Button'. 'Button'
is under the scope of element 'UserControl1', which already had a name
registered when it was defined in another scope.
I don't understand why that happens. Here's teh codez:
<UserControl x:Class="WpfApplication5.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"
mc:Ignorable="d" d:DesignHeight="300" d:DesignWidth="300"
x:Name="control">
<ContentPresenter Content="{Binding ElementName=control, Path=DataContext}" />
</UserControl>
<Window x:Class="WpfApplication5.MainWindow"
xmlns="http://schemas.microsoft.com/winfx/2006/xaml/presentation"
xmlns:x="http://schemas.microsoft.com/winfx/2006/xaml"
xmlns:local="clr-namespace:WpfApplication5"
Title="MainWindow" Height="350" Width="525">
<local:UserControl1>
<local:UserControl1.DataContext>
<Button x:Name="butt" />
</local:UserControl1.DataContext>
</local:UserControl1>
</Window>
How to do that properly?

You cannot name elements inside UserControls, someone considered this to be a bug but i do not know if this is the case, either way, this will not work. You could declare the Button as a resource of your Window and then insert it via StaticResource, then however the name will not be registered as a field in the window class.
Either way, do you really need the name?
Edit: Also see this question.