在ConfigureServices方法中添加DbContext服务后，有没有办法在Configure方法中更改它的连接字符串？

services.AddDbContext<MyDbContext>(options =>
    options.UseSqlServer(Configuration.GetConnectionString("DefaultConnection")));

"ConnectionStrings": {
  "DefaultConnection": "Data Source=.;Initial Catalog=MyDatabase;Integrated Security=True"
}

public void Configure(IApplicationBuilder app, IWebHostEnvironment env, IConfiguration configuration)
{
    var connectionString = configuration.GetConnectionString("DefaultConnection");
    var dbContextOptions = new DbContextOptionsBuilder<MyDbContext>()
        .UseSqlServer(connectionString)
        .Options;

    // 使用新的连接字符串创建DbContext实例
    using (var dbContext = new MyDbContext(dbContextOptions))
    {
        // 在这里可以对DbContext进行操作
    }

    // 其他配置和中间件
}