在ASP.NET Identity中创建角色组织单位结构可以通过以下步骤实现：

1. 创建角色表和组织单位表：

public class Role
{
    public int Id { get; set; }
    public string Name { get; set; }
    // 添加其他角色属性
}

public class OrganizationUnit
{
    public int Id { get; set; }
    public string Name { get; set; }
    // 添加其他组织单位属性
}

2. 创建角色-组织单位关联表：

public class RoleOrganizationUnit
{
    public int RoleId { get; set; }
    public Role Role { get; set; }
    public int OrganizationUnitId { get; set; }
    public OrganizationUnit OrganizationUnit { get; set; }
}

3. 修改IdentityDbContext以包括新的角色和组织单位表以及关联表：

public class ApplicationDbContext : IdentityDbContext
{
    public DbSet Roles { get; set; }
    public DbSet OrganizationUnits { get; set; }
    public DbSet RoleOrganizationUnits { get; set; }

    // 添加其他DbSet

    protected override void OnModelCreating(DbModelBuilder modelBuilder)
    {
        base.OnModelCreating(modelBuilder);

        // 配置角色-组织单位关联表的复合主键
        modelBuilder.Entity()
            .HasKey(r => new { r.RoleId, r.OrganizationUnitId });

        // 配置角色-组织单位关联表的外键关系
        modelBuilder.Entity()
            .HasRequired(r => r.Role)
            .WithMany()
            .HasForeignKey(r => r.RoleId);
        
        modelBuilder.Entity()
            .HasRequired(r => r.OrganizationUnit)
            .WithMany()
            .HasForeignKey(r => r.OrganizationUnitId);
    }
}

4. 在IdentityConfig.cs文件中添加角色和组织单位的管理方法：

public class ApplicationUserManager : UserManager
{
    // 添加构造函数

    public async Task AddToOrganizationUnitAsync(string userId, int organizationUnitId)
    {
        var user = await FindByIdAsync(userId);
        if (user == null)
        {
            return IdentityResult.Failed("User not found.");
        }

        user.OrganizationUnitId = organizationUnitId;
        var result = await UpdateAsync(user);

        return result;
    }

    public async Task AddToRoleAndOrganizationUnitAsync(string userId, int roleId, int organizationUnitId)
    {
        var user = await FindByIdAsync(userId);
        if (user == null)
        {
            return IdentityResult.Failed("User not found.");
        }

        user.RoleId = roleId;
        user.OrganizationUnitId = organizationUnitId;
        var result = await UpdateAsync(user);

        return result;
    }
}

5. 在应用程序中使用角色和组织单位的管理方法：

public class UserController : Controller
{
    private ApplicationUserManager _userManager;

    public UserController(ApplicationUserManager userManager)
    {
        _userManager = userManager;
    }

    public async Task AddToOrganizationUnit(string userId, int organizationUnitId)
    {
        var result = await _userManager.AddToOrganizationUnitAsync(userId, organizationUnitId);

        if (result.Succeeded)
        {
            // 添加成功的处理逻辑
        }
        else
        {
            // 添加失败的处理逻辑
        }

        return RedirectToAction("Index", "Home");
    }

    public async Task AddToRoleAndOrganizationUnit(string userId, int roleId, int organizationUnitId)
    {
        var result = await _userManager.AddToRoleAndOrganizationUnitAsync(userId, roleId, organizationUnitId);

        if (result.Succeeded)
        {
            // 添加成功的处理逻辑
        }
        else
        {
            // 添加失败的处理逻辑
        }

        return RedirectToAction("Index", "Home");
    }
}

以上是一种基本的实现方法，可以根据实际需求进行调整和扩展。