从 .net 核心库访问存储库

Question

我需要在 .net 核心库的存储库 class 中包装一些函数。但是我得到一个错误，我的构造函数没有正确的构造函数。我究竟做错了什么？这是我的 DBcontext 代码

 public class effMercContext : DbContext
{
    public DbSet<Department> Departments { get; set; }
    public DbSet<Employee> Employees { get; set; }
    public DbSet<Project> Projects { get; set; }
    public effMercContext(DbContextOptions<effMercContext> options)
        : base(options)
    {
    }
}
     public class EffMercDbContextFactory : IDbContextFactory<effMercContext>
{
    public effMercContext Create(DbContextFactoryOptions options)
    {
        var builder = new DbContextOptionsBuilder<effMercContext>();
        builder.UseSqlServer("Server=(localdb)\mssqllocaldb;Database=pinchdb;Trusted_Connection=True;MultipleActiveResultSets=true");
        return new effMercContext(builder.Options);
    }
}

到目前为止我的存储库class

public class EmployeeRepository
{
    public Employee GetByID(int id)
    {
        using (effMercContext db = new effMercContext())
        {

        }
    }
}

Answer 1

那是因为你在这里调用了不带参数的构造函数:

public Employee GetByID(int id) {
    using (effMercContext db = new effMercContext())
    {

    }
}

但是在你的 DbContext class 中你只有一个带有一个参数的构造函数：

public class effMercContext : DbContext {
    public effMercContext(DbContextOptions<effMercContext> options)
        : base(options) {
    }
}

查看这篇文章了解如何使用DbContextOptions：https://docs.efproject.net/en/latest/miscellaneous/configuring-dbcontext.html

Answer 2

您可以按如下方式修改您的 EmployeeRepository...

public class EmployeeRepository
{
    var optionsBuilder = new DbContextOptionsBuilder<effMercContext>();
    // add necessary options
    public Employee GetByID(int id)
    {
        using (effMercContext db = new effMercContext(optionsBuilder.Options))
        {

        }
    }
}

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从 .net 核心库访问存储库

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c#

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