Quick access. Search related threads. Remove From My Forums. Answered by:. Archived Forums V. Visual Basic Express Edition. Sign in to vote. I'm not entirely sure how to frame the question, but here goes.
Allan Big Al. Saturday, February 18, PM. Basicly, this is specifying that 'ElementHost1. Child' is an object of the 'UserControl1' type Dragging a WindowsXamlHost from the Toolbox to the designer is not supported.
Before you show that control in the UI of your application, you'll have to associate it with a WindowsXamlHost control.
Here's an example that demonstrates how to do this. In some situations, you might want to create instances of UWP controls without having to first create WindowsXamlHost controls.
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Is this page helpful? The only disadvantage to using the NotifyIcon in a WPF window is that there's no design-time support. It's up to you to create the NotifyIcon by hand, attach event handlers, and so on. Once you supply an icon using the Icon property and set Visible to true, your icon will appear in the system tray shown in Figure 1. When your application ends, you should call Dispose on the NotifyIcon to remove it from the system tray immediately. The NotifyIcon does use some Windows Forms—specific bits.
For example, it uses a Windows Forms context menu, which is an instance of the System. ContextMenuStrip class. Creating all the objects for a menu in code and attaching event handlers is more than a little tedious. Fortunately, there's a simpler solution when building a WPF application that uses the NotifyIcon—you can create a component class. A component class is a custom class that derives from System. It provides two features that ordinary classes lack: support for deterministically releasing resources when its Dispose method is called and design-time support in Visual Studio.
Every custom component gets a design surface technically known as the component tray where you can drag and configure other classes that implement IComponent, including Windows Forms. In other words, you can use the component tray to build and configure a NotifyIcon, complete with a context menu and event handlers. Here's what you need to do to build a custom component that wraps an instance of the NotifyIcon and includes a context menu:.
Open or create a new WPF project. Pick the Component Class template, supply a name for your custom component class, and click Add. Drop a NotifyIcon onto the design surface of your component. At this point, Visual Studio adds the reference you need to the System. However, it won't add a reference to the System. You must add a reference to System. This will represent the context menu for your NotifyIcon.
Figure 2 shows both ingredients in Visual Studio. Select the NotifyIcon and configure it using the Properties window. You'll want to set the following properties: Text the tooltip text that appears when you hover over the NotifyIcon , Icon the icon that appears in the system tray , and ContextMenuStrip the ContextMenuStrip you added in the previous step.
You'll see a collection editor that you can use to add the menu items which you should place after the root menu item. Give them easily recognizable names because you'll need to connect the event handlers yourself. To see your component class code, right-click the component in the Solution Explorer and choose View Code. Don't open the. This file contains the code that Visual Studio generates automatically, which is combined with the rest of the component code using partial classes.
Add the code that connects your menu's event handlers. Here's an example that adds the event handler for two menu commands—a Close button and a Show Window button:. Now that you've created the custom component class, you simply need to create an instance of it when you want to show the NotifyIcon. This triggers the designer code in your component, which creates the NotifyIcon object, making it visible in the system tray.
Removing the system tray icon is just as easy—you simply need to call Dispose on your component. This step forces the component to call Dispose on all contained components, including the NotifyIcon.
Here's a custom application class that shows the icon when the application starts and removes it when the application ends:. To complete this example, make sure you remove the StartupUri attribute from the App. This way, the application starts by showing the NotifyIcon but doesn't show any additional windows until the user clicks an option from the menu. This example relies on one more trick. A single main window is kept alive for the entire application and shown whenever the user chooses Show Window from the menu.
However, this runs into trouble if the user closes the window. There are two possible solutions—you can re-create the window as needed the next time the user clicks Show Window, or you can intercept the Window.
Closing event and quietly conceal the window instead of destroying it.
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