Project suddenly fails to build with 0 error Xamarin.Forms

Question

I've been working on this project for about a week without any build problem, but suddenly my project fails to build with 0 error showed on the screen, but I found these 2 alerts in the output window. How do I fix this?

#1

warning MSB3277: Found conflicts between different versions of "System.Numerics.Vectors" that 
could not be resolved.
2>D:\Program Files (x86)\Microsoft Visual 
Studio\2019\Community\MSBuild\Current\Bin\Microsoft.Common.CurrentVersion.targets(2202,5): 
warning MSB3277: There was a conflict between "System.Numerics.Vectors, Version=2.0.5.0, 
Culture=neutral, PublicKeyToken=b03f5f7f11d50a3a" and "System.Numerics.Vectors, 
Version=4.1.3.0, Culture=neutral, PublicKeyToken=b03f5f7f11d50a3a".
2>D:\Program Files (x86)\Microsoft Visual 
Studio\2019\Community\MSBuild\Current\Bin\Microsoft.Common.CurrentVersion.targets(2202,5): 
warning MSB3277:     "System.Numerics.Vectors, Version=2.0.5.0, Culture=neutral, 
PublicKeyToken=b03f5f7f11d50a3a" was chosen because it was primary and 
"System.Numerics.Vectors, Version=4.1.3.0, Culture=neutral, PublicKeyToken=b03f5f7f11d50a3a" 
was not.
2>D:\Program Files (x86)\Microsoft Visual 
Studio\2019\Community\MSBuild\Current\Bin\Microsoft.Common.CurrentVersion.targets(2202,5): 
warning MSB3277:     References which depend on "System.Numerics.Vectors, Version=2.0.5.0, 
Culture=neutral, PublicKeyToken=b03f5f7f11d50a3a" [D:\Program Files (x86)\Microsoft References 
which depend on "System.Numerics.Vectors, Version=4.1.3.0, Culture=neutral, 
PublicKeyToken=b03f5f7f11d50a3a" [].
2>D:\Program Files (x86)\Microsoft Visual 
Studio\2019\Community\MSBuild\Current\Bin\Microsoft.Common.CurrentVersion.targets(2202,5): 
warning MSB3277:         
C:\Users\Lenovo\.nuget\packages\system.text.json\5.0.2\lib\netstandard2.0\System.Text.Json.dll
2>D:\Program Files (x86)\Microsoft Visual 
Studio\2019\Community\MSBuild\Current\Bin\Microsoft.Common.CurrentVersion.targets(2202,5): 
warning 

#2

CSC : error CS0006: Metadata file
'C:\Users\Lenovo\source\repos\Project11\Project11\Project11\bin\Debug\
netstandard2.0\ref\Project11.dll' could not be found

Answer 1

I have fixed this issue "CSC : error CS0006: Metadata file 'C:\\Users\\Lenovo\\source\\repos\\Project11\\Project11\\Project11\\bin\\Debug
netstandard2.0\\ref\\Project11.dll' could not be found"

The Visual Studio did not show me any error, but as I went through PageView one by one, I noticed that one of my "Click_Event_Button" has an incorrect name from the xaml.cs file.

Hope this might help other users who have the same issue.