C# InvalidOperationException: Unable to resolve service for type 'AutoMapper.Mapper'

报错信息：

InvalidOperationException: Unable to resolve service for type 'AutoMapper.Mapper'

while attempting to activate 'BLL.Implementation.Report'.

检查后发现名称写错了

错误：

private readonly Mapper _mapper;

正确的是：

private readonly IMapper _mapper;

另外一种情况是没有在startup类的ConfigureServices中注入automapper依赖

先在Nuget里下载AutoMapper 之后再startup文件引用，最后注入依赖