网络核心：使用变量类型声明新的DbContext Download

var dbContextType = dbContextAssembly.GetTypes().Where(d => d.BaseType.Name == "DbContext").First();
var businessDbContext = Activator.CreateInstance(dbContextType) as DbContext;
DbContextOptionsBuilder optionsBuilder = new DbContextOptionsBuilder();

// Attempting Line Below
var options = new DbContextOptionsBuilder<dbContextType>().UseInMemoryDatabase(databaseName: "Test").Options;

  

错误：dbContextType是一个变量，但是像类型一样使用。

最终目标是根据上述程序集中的类型声明一个新的DbContext。

示例：

var onlineStoreContext = new OnlineStoreContext(options)

1 个答案:

答案 0 :(得分：0)

您快到了。您可以使用以下方法创建通用类型的实例：

Type dbContextType = typeof(MyDbContext);
// 1st get type of Generic object
Type dbContextOptionsBuilderType = typeof(DbContextOptionsBuilder<>);
// 2nd call "MakeGenericType" method by passing the "T" type
Type dbContextOptionsBuilderGenericType = dbContextOptionsBuilderType.MakeGenericType(dbContextType);
// 3rd create an instance by using "Activator.CreateInstance"
DbContextOptionsBuilder dbContextOptionsBuilderInstance = Activator.CreateInstance(dbContextOptionsBuilderGenericType) as DbContextOptionsBuilder;

DbContextOptions dbContextOptions = dbContextOptionsBuilderInstance.UseInMemoryDatabase(databaseName: "Test").Options;

“ How to use local variable as a type? Compiler says "it is a variable but is used like a type"”是原始解决方案。