I got an error when I built my application. The error said 'No xmlns declaration for prefix "local". Because I used the xaml, I found the compiler did not check the error in xaml file. As a result, it got the runtime error like. This is very easy to solve. Please search all xaml files you used local has this xmlns:local="clr-namespace:[your namespace]"

After I had installed a new component in my Xamarin project, I got an error like that: C:\Users\[username]\ AppData\Local\Xamarin\[packages]\[version]\class.jar missing.
I found the problems are caused the downloading packages are failed before. The Xamarin is not smart enough to re-download automatic.
The solution is simply. I only need to delete all zip files under Error: C:\Users\[username]\AppData\Local\Xamarin\zips and the package folder in the error message. Then I need to rebuild the project. The packages will be download again. The project will build successfully.

I am building an app with a map component. I put the Map Control on a navigation page. But I put this code on the button click event.

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Even the UI I built is very simple; I need to load some icons in the UI. I have used navigation page. After I had navigated two pages, then I got an exception, OutOfMemoryException. That is because Bitmap Decode is used a lot of memory. I found we should avoid using:

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Then the problem will solve.

I started to build a library management system for small organisations. This system doesn't require a pc at all. It will works in any iOS and Android devices. It used a camera in the device as a bar scanner. I used an open source framework ZXing.Net.Mobile to do that. I found when I fire the scanner activity, it got a blank back screen. I initialized the framework

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