1. 创建ViewModel类，包含需要展示的属性和它们的getter和setter方法：

public class ActivityViewModel
{
    public int ActivityId { get; set; }
    public string Name { get; set; }
    public DateTime Date { get; set; }
    public List Identities { get; set; }
}
public class IdentityViewModel
{
    public int IdentityId { get; set; }
    public string Name { get; set; }
    public string Email { get; set; }
}

2. 在Controller类中创建Action方法，从数据源中获取Activity和Identity数据，并使用ViewModel类包装它们：

public IActionResult Activity()
{
    var activities = _activityRepository.GetActivities();
    var identities = _identityRepository.GetIdentities();

    var viewModel = new ActivityViewModel
    {
        ActivityId = activities.Id,
        Name = activities.Name,
        Date = activities.Date,
        Identities = identities.Select(i => new IdentityViewModel
        {
            IdentityId = i.Id,
            Name = i.Name,
            Email = i.Email
        }).ToList()
    };

    return View(viewModel);
}

3. 创建对应的Activity视图，在视图中使用ViewModel类的属性来展示数据：

@model ActivityViewModel

@Model.Name
Date: @Model.Date.ToShortDateString()


    @foreach (var identity in Model.Identities)
    {
        
@identity.Name - @identity.Email
    }