I have a problem with figuring out how to refer to a Canvas in another XAML file in my project.
For example there is a Canvas object containing some labels, images called MyLayout and is stored in MyLayout.xaml
I want to use this Canvas in the main Window of the application in Window.xaml. How can this be done? There will be multiple layouts that will be needed to be loaded into the Window.
All the XAML is within the project and compiled it cannot be loaded from a file.
How do I reference the Canvas Object in the MyLayout.xaml file in the Window.xaml?
This can be in XAML, VB.NET code or even C#.
I have searched for hours trying to figure this out. How to use an object from one XAML file in another? How is this done?
Thanks in advance. I hope someone knows how to do this.
Have you thought about using a UserControl or ControlTemplate?
Since your Canvas object is really a subclass of Canvas, that subclass is defined in your assembly. You can reference objects defined in other namespaces by adding another xmlns attribute to the root XAML object.
Something like this (assuming that your Canvas subclass is called MyCanvas in the MyNamespace namespace):
<Window x:Class="MyNamespace.Window1"
xmlns="http://schemas.microsoft.com/winfx/2006/xaml/presentation"
xmlns:x="http://schemas.microsoft.com/winfx/2006/xaml"
xmlns:local="clr-namespace:MyNamespace">
<local:MyCanvas />
</Window>
You can set the properties of the MyCanvas class like any other object.
Related
I was searching for a 'waiting' animation for silverlight after I realized that GIF animations doesn't work in Silverlight. I found an excellent animation here. How can I use this in my application. Do I need to create any custom controls. I just want to place this over my dataview until the items gets populated.
Check out this implementation in Coproject on codeplex.
If you're using mvvm, you can wrap operations in a using. The BusyWatcher gets injected into the ViewModel using MEF.
[Import(RequiredCreationPolicy = CreationPolicy.Shared)]
public IBusyWatcher Busy { get; set; }
then:
using (Busy.GetTicket())
{
...
}
Create UserControl call it something sensible like WaitAnim1.
The sample you point to overuses Grids. The outer grid represent in your case the UserControl. Do the following to make your usercontrol from that original code:-
copy the xmlns:sys="clr-namespace:System;assembly=mscorlib" namespace to your UserControl element.
copy the whole Grid.Resources to directly under the <UserControl> tag and rename Grid.Resources to UserControl.Resources
copy whole <Grid x:Name="LayoutRoot" > element from the source code and replace the one in your usercontrol with it.
You now have a usercontrol that when displayed will show the animation.
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.
Usually, the WPF controls are declared in the .xaml files and not in the code behind (.xaml.cs files). However, sometimes I need to use some of those controls in code behind in order to manipulate them. How can I get the handle of such a control if it "resides" in the xaml file?
You can use the FindName() method of the ControlTemplate class.
// Finding the grid that is generated by the ControlTemplate of the Button
Grid gridInTemplate = (Grid)myButton1.Template.FindName("grid", myButton1);
I'm unsure about what you're asking, so I'll try and answer both instances that I'm interpreting as your question.
1)
If you want to declare an explicit control, and then edit it directly, all you have to do is set the name property like such:
<Canvas x:Name="myCanvas"/>
You can then access the canvas through the Name as such:
myCanvas.Background = Brushes.Blue;
2)
If you're looking to declare a generic control, and then use it multiple times, you can do it like this:
<Window>
<Window.Resources>
<Ellipse x:Key="myEllipse" Height="10" Width="10">
</Window.Resources>
</Window>
You can then access that predefined control using this syntax in code:
Ellipse tempEllipse = (Ellipse)FindResource("MyEllipse");
If you want to use the Resourse as a template for multiple controls, add x:Shared="false".
I'm working on a wpf application, and up until recently, I had a ResourceDictionary inside my main window's resources part of the xaml. The resource dictionary contained an DataTemplate that was used to style several listboxes in the window. The xaml for this datatemplate contained pointers to event handlers, eg:
<Button n:Name="btnClickMe" Content="Click Me!" LeftMouseButtonUp="btnClickMe_Click" />
I recently decided to split the content of the window up into separate user controls, and to move my ResourceDictionary into it's own file. But, of course, there isn't a code-behind file for a resource dictionary file. How can I wire this up, with things split up as I've described?
Thanks in advance!
You can add a code-behind to a ResourceDictionary; just make sure your class names are referenced correctly. For instance, in the ResourceDictionary if you were working with AppStyles.xaml the XAML file would have a class of:
x:Class="Client.App.Shell.themes.AppStyles"
In the code-behind, AppStyles.xaml.cs, you would make sure to have the class:
namespace Client.App.Shell.themes
{
public partial class AppStyles
...
You can add a new class and name it with the same name as your resource dictionary plus the .cs extension and Visual Studio will automatically set things up so it becomes the code behind file.
For example if you have a resource dictionary called Buttons.xaml, add a file called Buttons.xaml.cs.
You should consider using RoutedCommands, I am thinking.
there are many many resources online, here are a couple that might help you.
http://msdn.microsoft.com/en-us/library/ms752308.aspx
http://www.devx.com/DevX/Article/37893/0/page/1
Is it possible to set code behind a resource dictionary in WPF. For example in a usercontrol for a button you declare it in XAML. The event handling code for the button click is done in the code file behind the control. If I was to create a data template with a button how can I write the event handler code for it's button click within the resource dictionary.
I think what you're asking is you want a code-behind file for a ResourceDictionary. You can totally do this! In fact, you do it the same way as for a Window:
Say you have a ResourceDictionary called MyResourceDictionary. In your MyResourceDictionary.xaml file, put the x:Class attribute in the root element, like so:
<ResourceDictionary xmlns="http://schemas.microsoft.com/winfx/2006/xaml/presentation"
xmlns:x="http://schemas.microsoft.com/winfx/2006/xaml"
x:Class="MyCompany.MyProject.MyResourceDictionary"
x:ClassModifier="public">
Then, create a code behind file called MyResourceDictionary.xaml.cs with the following declaration:
namespace MyCompany.MyProject
{
partial class MyResourceDictionary : ResourceDictionary
{
public MyResourceDictionary()
{
InitializeComponent();
}
... // event handlers ahead..
}
}
And you're done. You can put whatever you wish in the code behind: methods, properties and event handlers.
== Update for Windows 10 apps ==
And just in case you are playing with UWP there is one more thing to be aware of:
<Application x:Class="SampleProject.App"
xmlns="http://schemas.microsoft.com/winfx/2006/xaml/presentation"
xmlns:x="http://schemas.microsoft.com/winfx/2006/xaml"
xmlns:rd="using:MyCompany.MyProject">
<!-- no need in x:ClassModifier="public" in the header above -->
<Application.Resources>
<ResourceDictionary>
<ResourceDictionary.MergedDictionaries>
<!-- This will NOT work -->
<!-- <ResourceDictionary Source="/MyResourceDictionary.xaml" />-->
<!-- Create instance of your custom dictionary instead of the above source reference -->
<rd:MyResourceDictionary />
</ResourceDictionary.MergedDictionaries>
</ResourceDictionary>
</Application.Resources>
</Application>
I disagree with "ageektrapped"... using the method of a partial class is not a good practice. What would be the purpose of separating the Dictionary from the page then?
From a code-behind, you can access a x:Name element by using:
Button myButton = this.GetTemplateChild("ButtonName") as Button;
if(myButton != null){
...
}
You can do this in the OnApplyTemplate method if you want to hookup to controls when your custom control loads. OnApplyTemplate needs to be overridden to do this. This is a common practice and allows your style to stay disconnected from the control. (The style should not depend on the control, but the control should depend on having a style).
Gishu - whilst this might seem to be a "generally not to be encouraged practice" Here is one reason you might want to do it:
The standard behaviour for text boxes when they get focus is for the caret to be placed at the same position that it was when the control lost focus. If you would prefer throughout your application that when the user tabs to any textbox that the whole content of the textbox was highlighted then adding a simple handler in the resource dictionary would do the trick.
Any other reason where you want the default user interaction behaviour to be different from the out of the box behaviour seems like good candidates for a code behind in a resource dictionary.
Totally agree that anything which is application functionality specific ought not be in a code behind of a resource dictionary.
Adding on....these days, with the advent of {x:Bind ...}, if you want to put your DataTemplate into a shared ResourceDictionary file, you are required to give that file a code behind.
XAML is for constructing object graphs not containing code.
A Data template is used to indicate how a custom user-object is to be rendered on screen... (e.g. if it is a listbox item) behavior is not part of a data template's area of expertise. Redraw the solution...