I'm having a problem accessing a Panel control defined on the XAML of a page, the XAML is defined this way:
<UserControl
x:Class="PhoneBook.SilverlightMainPage"
xmlns="http://schemas.microsoft.com/winfx/2006/xaml/presentation"
xmlns:x="http://schemas.microsoft.com/winfx/2006/xaml"
mc:Ignorable="d" Width="400" Height="300" d:DesignWidth="993" d:DesignHeight="887">
<Grid x:Name="LayoutRoot" />
</UserControl>
The class is defined like this:
public partial class SilverlightMainPage : UserControl
{
public SilverlightMainPage()
{
InitializeComponent();
}
}
And I'm trying to instantiate it this way:
var silverlightMainPage = new PhoneBook.SilverlightMainPage();
SomeMethod((silverlightMainPage.LayoutRoot);
What I find strange is that when I put the dot after the object instance, it actually list LayoutRoot as one of the members, but when I try to compile the application it says that there's no member with that name.
Any ideas of what can be hapenning?
Thanks
EDIT: I also tried creating a property on the SilverlightMainPage class that returned the LayoutRoot element, but it also says that the class doesn't contain a definition for Layout root.
Is there any chance that you're trying to access SilverlightMainPage.LayoutRoot from a different assembly? In the MainPage.g.i.cs file, LayoutRoot (and all other controls defined in XAML) are marked "internal", i.e.:
internal System.Windows.Controls.Grid LayoutRoot;
You might want to try creating a public rather than an internal property that does a FindName("LayoutRoot") and returns the appropriate control.
Actually I found the problem.
I was generating the project automatically with a tool built by someone else in the company.
I did some extra tests and added a new UserControl to the project and tried to access the LayoutRoot from a property in the code behind, and it worked.
Then copied the exact same code to the file with the problem (just changing the class name) and it didn't compile.
Then I checked the project file, and found a section like this:
<ItemGroup>
<Compile Include="SilverlightMainPage.xaml.cs">
<DependentUpon>SilverlightMainPage.xaml</DependentUpon>
</Compile>
</ItemGroup>
Which for some reason was causing the compilation to fail.
I removed that section and now everything works fine.
Thanks for your answers though.
Related
This is my first time ever doing anything with XAML and I'm a bit lost.
I'm trying to add a DataTemplateSelector to my XAML page using the instructions found here.
However I'm stuck on the part where I'm supposed to "declare the TaskListDataTemplateSelector as a resource". This is the example given:
<Window.Resources>
...
<local:TaskListDataTemplateSelector x:Key="myDataTemplateSelector"/>
...
</Window.Resources>
However, the top level tag in the XAML document is <UserControl>, and I don't see anything about Window or Window.Resources.
Under the <UserControl> tag is a <UserControl.Resources> tag, but when I try to put the example code there, it gives me an error saying "The namespace prefix 'local' is not defined". I tried replacing "local" with the actual namespace, but got the same error.
The custom DataTemplateSelector class is in the codebehind for the XAML page, and is in the same namespace.
For anyone who googled this question like I did:
I think I found the answer.
You need to define the local prefix in your XAML file.
This can be done by placing the following namespace argument in the root element:
xmlns:local="clr-namespace:AssemblyName"
Change "AssemblyName" in your erm.. assembly's name.
I have create a solution which contains two project:
project 1. used for define some common classes, such as:
public class ApplicationCommands
{
private static DelegateCommand _edit;
public static DelegateCommand Edit
{
get
{
if (_edit== null)
_edit= new DelegateCommand(EditExecute, EditCanExecute);
return _edit;
}
}
}
project 2. will use the command defined in the common class assembly in XAML is like:
<Window x:Class="Edit.MainWindow"
xmlns="http://schemas.microsoft.com/winfx/2006/xaml/presentation"
xmlns:x="http://schemas.microsoft.com/winfx/2006/xaml"
xmlns:edit="clr-namespace:Edit;assembly=Edit"
Title="MainWindow"
Height="600"
Width="700">
<Grid>
<Button Command="edit:ApplicationCommands.Edit"/>
</Grid>
</Window>
When I run the application the exception was thrown at line:
<Button Command="edit:ApplicationCommands.Edit"/>
and the exception message is "{"Type reference cannot find type named '{clr-namespace:Edit;assembly=Edit}ApplicationCommands'."}". But when I open the dll, the ApplicationCommands is in the dll.
When I move the ApplicationCommands class to the project 2 and the used it it works perfectly.
Can anyone tell me, do I miss anything for exposing the class or static members from one assembly to others, or consuming the class or static members exposed by other assembly.
Try with Binding's in the Command
<Button Command="{Binding Source="{x:Static edit:ApplicationCommands.Edit}"/>
To avoid this race condition, assign the edit command to a stack variable after the initialization of the page and see if the same happens. Something about loading a DLL from xaml appears to be in a race condition. If it still occurs, assign it to a property on the page or VM and bind to it from the xaml.
How to call a method or use a variable from a different namespace in another class in another namespace in a xaml file?
You can add references to namespaces in your xaml root element like this...
<UserControl
x:Class="MySolution.MyNamespace.MyControl"
xmlns="http://schemas.microsoft.com/winfx/2006/xaml/presentation"
xmlns:x="http://schemas.microsoft.com/winfx/2006/xaml"
xmlns:another="clr-namespace:MySolution.AnotherNamespace">
You can then reference objects from within that namespace in your xaml, for example, I want to bind the Command property of my Button to a command in AnotherNamespace...
<Button Command="{x:Static another:MyCommand}"/>
I can't really offer much more help than that though without knowing what you actually hope to achieve.
This is my first foray into custom controls, and it's not going well. I have a custom graph control derived from Canvas.
namespace Grapher2 {
public class SeriesManager : Canvas {
public SeriesManager() {
...
}
}
}
It's defined in the same project and namespace as my app. I tried adding a reference to the control in XAML as follows:
<Window x:Class="Grapher2.Window1"
xmlns="http://schemas.microsoft.com/winfx/2006/xaml/presentation"
xmlns:x="http://schemas.microsoft.com/winfx/2006/xaml"
xmlns:graph="clr-namespace:Grapher2"
Title="Grapher" Width="800" Height="600">
<StackPanel Name="container" Width="700" Height="500">
<graph:SeriesManager Name="seriesManager" Width="700" Height="500" />
</StackPanel>
But when I try to reference the control name "seriesManager" in the code-behind for the Window, I get "The name 'seriesManager' does not exist in the current context."
Furthermore, the XAML editor will not render the Window, giving a huge stack trace with the error: "Type 'MS.Internal.Permissions.UserInitiatedNavigationPermission' in Assembly 'PresentationFramework, Version=3.0.0.0, Culture=neutral, PublicKeyToken=31bf3856ad364e35' is not marked as serializable."
I imagine the solution is something stupidly simple for anyone who's done custom controls. But I'm stumped.
did you try x:Name="seriesManager" in your xaml?
Edit: This may not be the issue seeing how you said your xaml isn't rendering. I'm guessing once you get the xaml to render in the designer... the code behind will work better.
Edit 2: Whenever I've had a problem with the designer rendering, it's because I'm doing something in the constructor of my custom control. Check your SeriesManager to see if you are doing something in its constructor that is causing a problem. Maybe you are referencing something that doesn't exist yet. If you do have extra code in your constructor, consider moving it to the UserControl_Loaded event.
Backing up Scott's answer here, since he helped me solve it:
What I did wrong was trying to access the control BEFORE InitializeComponent(), but was confused by 2 other error messages somewhere else in the code.
Just in case someone else has this error.
I have a very simple user control, and I'm trying to instantiate it in XAML. I find that when I go a bit overzealous with the namespacing, I run into problems with x:Name.
Here is my UserControl:
<UserControl x:Class="UserControlTest.UserControl1"
xmlns="http://schemas.microsoft.com/winfx/2006/xaml/presentation"
xmlns:x="http://schemas.microsoft.com/winfx/2006/xaml" Width="300" Height="300">
<Grid>
<Label Name="Label1">Label</Label>
</Grid>
</UserControl>
Here is the code-behind for the UserControl:
Namespace UserControlTest
Partial Public Class UserControl1
End Class
End Namespace
Now, note that I have the root namespace of my VB.Net project set to "UserControlTest". Knowing that, have a look at my main window:
Here is my main window:
<Window x:Class="Window1"
xmlns="http://schemas.microsoft.com/winfx/2006/xaml/presentation"
xmlns:x="http://schemas.microsoft.com/winfx/2006/xaml"
xmlns:control="clr-namespace:UserControlTest.UserControlTest"
Title="Window1" Height="300" Width="300">
<Grid>
<control:UserControl1 />
</Grid>
</Window>
See how the control alias needs to have "UserControlTest.UserControlTest"? That's because I have the root namespace of my project set to UserControlTest, and I have defined the namespace of the UserControl to be UserControlTest, also. If I don't use a namespace for the UserControl, I don't have any troubles.
However, because I have done this, the build fails should I try to apply an x:Name to the UserControl, as follows:
<control:UserControl1 x:Name="test"/>
That will fail the build, with this error:
Type 'UserControlTest.UserControlTest.UserControl1' is not defined.
Can anybody explain why? Do I need to avoid putting my UserControls into namespaces just so I can give them x:Name values? I'd like to manipulate my UserControls from code-behind, and without an x:Name, I'm up the creek. But I don't want to sacrifice namespace usage just to get it!
Thanks very much.
I had the same problem (after rebuilding the project, first it worked fine...). I put UserControl into separate namespace.
What is the namespace defined as in the code-behind of your user control?
If your project was called Foo and you had a folder called Controls inside that project, any new user control added to that folder would be given the namespace Foo.Controls.
Then in your XAML you can reference it like so:
xmlns:Controls="clr-namespace:Foo.Controls"
...
<Controls:UserControl1 x:Name="uc1"/>
It seems like you have a naming issue.
EDIT:
Here's how I'm doing it in a project of mine.
StatusBar.xaml.cs
namespace Client.Controls.UserControls
{
public partial class StatusBar : UserControl
{
...
}
}
StatusBar.xaml
<UserControl x:Class="Client.Controls.UserControls.StatusBar">
</UserControl>
Main.xaml.cs
using Client.Controls.UserControls;
namespace Client
{
public partial class Main : Window
{
...
}
}
Main.xaml
<Window x:Class="Client.Main"
xmlns:UserControls="clr-namespace:Client.Controls.UserControls">
<UserControls:StatusBar x:Name="mainStatusBar" />
</Window>
I encountered the same problem in a vb.net project, and despite trying the suggestions here and elsewhere, could not solve the issue. In fact, I was able to take the exact same code out of our project to a new project, and it worked just fine (as far as I could determine all the configuration in the new project was identical). In the solution provided by David, I notice he is using c# - I am wondering if this is some weirdness associated with vb.net.
In the end, the user control I needed to use was quite simple and I implemented it as a resource ControlTemplate to get around the issue. Sorry I don't have a better answer, I am really not happy wih my findings...