Log file from Visual Studio is only supported for C++ projects. You just have to work with the output window for others.
See this similar thread: VS2010: minimal build log in output and detailed log in log file
And in case you happen to do this for a C++ project, the file is at:
… build log in the intermediate files directory
… The path and name of the build log is represented by the MSBuild macro
expression,$(IntDir)\$(MSBuildProjectName).log.