Is there anyway to adjust the width of the MasterPage because it is too wide ?
Not in the Forms API.
This post suggests a Forms workaround that may work for Android
For iOS anyway you'd have to override the platform specific default behavior with a renderer, some options are discussed here but to answer your question, you currently can't adjust the with via a property change......unfortunately.
We have to write CustomRenderer for MasterDetailPage
Follow below link
Do you have a solution for this yet? If so, please could you tell us If not, then could you check here for another possible solution: https://forums.xamarin.com/discussion/comment/317997#Comment_317997
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