ProgramModelEntities = _migrateRepository.GetAllWithNoTrackingAsync<ProgramModelEntity>().ToList(); Programmes = ProgramModelEntities.Select(program => { CProgramme p = new CProgramme() { Id = new Guid(program.Id), Name = program.Name, SchoolId = SQIConstants.SYS_School_ID, Description = program.Description, CreatedById = String.IsNullOrEmpty(program.CreatedBy) ? new Guid("e306ca07-a21b-40fd-935a-343cfe369001") : new Guid(program.CreatedBy), CreatedTime = program.CreatedOn == null ? new DateTime().Ticks : program.CreatedOn.Value.Ticks, ModifiedById = String.IsNullOrEmpty(program.ModifiedBy) ? new Guid("e306ca07-a21b-40fd-935a-343cfe369001") : new Guid(program.ModifiedBy), ModifiedTime = program.ModifiedOn == null ? new DateTime().Ticks : program.ModifiedOn.Value.Ticks, Duration = 1 }; if (!String.IsNullOrEmpty(program.ProgramAdmins)) { var admins = program.ProgramAdmins.Split(";"); ResourceAccesses.Add(admins.Select(admin => new CResourceAccess() { Id = Guid.NewGuid(), UserId = new Guid(admin), RoleType = RoleType.ProgrammeAdmin, ResourceId = new Guid(program.Id), ResourceLevel = ResourceLevel.Programme } ).ToList()); } ResourcesList.Add(new CResources { Id = new Guid(program.Id), ResourceLevel = ResourceLevel.Programme, SchoolId = SQIConstants.SYS_School_ID, ProgrammeId = new Guid(program.Id), }); return p; } ).ToList(); 优化下这段代码

以下是对这段代码的一些优化建议：

1. 使用异步方法来获取数据，可以提高性能。例如，可以使用 `ToListAsync()` 替代 `ToList()`。

2. 使用 LINQ 的 Select 方法来进行对象的转换，可以让代码更简洁易读。例如，可以使用如下的代码替代 `ProgramModelEntities.Select()`：

Programmes = await _migrateRepository.GetAllWithNoTrackingAsync<ProgramModelEntity>()
    .Select(program => new CProgramme
    {
        Id = new Guid(program.Id),
        Name = program.Name,
        SchoolId = SQIConstants.SYS_School_ID,
        Description = program.Description,
        CreatedById = String.IsNullOrEmpty(program.CreatedBy)
            ? new Guid("e306ca07-a21b-40fd-935a-343cfe369001")
            : new Guid(program.CreatedBy),
        CreatedTime = program.CreatedOn?.Ticks ?? new DateTime().Ticks,
        ModifiedById = String.IsNullOrEmpty(program.ModifiedBy)
            ? new Guid("e306ca07-a21b-40fd-935a-343cfe369001")
            : new Guid(program.ModifiedBy),
        ModifiedTime = program.ModifiedOn?.Ticks ?? new DateTime().Ticks,
        Duration = 1
    })
    .ToListAsync();

3. 对于资源列表和资源访问列表的操作，可以使用 LINQ 的 SelectMany 方法和 Where 方法来替代 foreach 循环。例如，可以使用如下的代码替代 `if (!String.IsNullOrEmpty(program.ProgramAdmins))` 和 `ResourcesList.Add()`：

var programmeAdmins = program.ProgramAdmins?.Split(';');

if (programmeAdmins?.Any() == true)
{
    ResourceAccesses.AddRange(programmeAdmins
        .Select(admin => new CResourceAccess
        {
            Id = Guid.NewGuid(),
            UserId = new Guid(admin),
            RoleType = RoleType.ProgrammeAdmin,
            ResourceId = new Guid(program.Id),
            ResourceLevel = ResourceLevel.Programme
        }));
}

ResourcesList.AddRange(programmeAdmins?.Select(admin => new CResources
{
    Id = new Guid(program.Id),
    ResourceLevel = ResourceLevel.Programme,
    SchoolId = SQIConstants.SYS_School_ID,
    ProgrammeId = new Guid(program.Id),
}) ?? Enumerable.Empty<CResources>());

综上所述，以下是经过优化后的代码：

Programmes = await _migrateRepository.GetAllWithNoTrackingAsync<ProgramModelEntity>()
    .Select(program => new CProgramme
    {
        Id = new Guid(program.Id),
        Name = program.Name,
        SchoolId = SQIConstants.SYS_School_ID,
        Description = program.Description,
        CreatedById = String.IsNullOrEmpty(program.CreatedBy)
            ? new Guid("e306ca07-a21b-40fd-935a-343cfe369001")
            : new Guid(program.CreatedBy),
        CreatedTime = program.CreatedOn?.Ticks ?? new DateTime().Ticks,
        ModifiedById = String.IsNullOrEmpty(program.ModifiedBy)
            ? new Guid("e306ca07-a21b-40fd-935a-343cfe369001")
            : new Guid(program.ModifiedBy),
        ModifiedTime = program.ModifiedOn?.Ticks ?? new DateTime().Ticks,
        Duration = 1
    })
    .ToListAsync();

var programmeResources = Programmes.SelectMany(programme => new[]
{
    new CResources
    {
        Id = programme.Id,
        ResourceLevel = ResourceLevel.Programme,
        SchoolId = SQIConstants.SYS_School_ID,
        ProgrammeId = programme.Id
    }
});

var programmeAdminResources = Programmes.SelectMany(programme =>
{
    var programmeAdmins = programme.ProgramAdmins?.Split(';');
    
    return programmeAdmins?.Select(admin => new CResourceAccess
    {
        Id = Guid.NewGuid(),
        UserId = new Guid(admin),
        RoleType = RoleType.ProgrammeAdmin,
        ResourceId = programme.Id,
        ResourceLevel = ResourceLevel.Programme
    }) ?? Enumerable.Empty<CResourceAccess>();
});

ResourcesList.AddRange(programmeResources);
ResourceAccesses.AddRange(programmeAdminResources);