public void Clear()
When a merged cell region is removed, the top-left cell in the region will retain the region's value. All other cells in the region will have a null value. In addition, all cells in the merged region will have the region's cell format when it is removed.
Target Platforms: Android 4.4+, iOS 8+
Development Environments: Visual Studio 2015+, Visual Studio for Mac Preview, Xamarin for Visual Studio 4.2+