如何在 ASP.NET Core 2.x 中以会话状态存储和检索对象？

Question

我如何将 EmployeeId 和 DesignationId 添加到对象，然后从会话状态中检索它？

这是我的登录控制器代码：

DataTable dt = sql.GetDataTable("select * from EmpDetails where EmailId = '" + EmailId + "'");
string strempstatus = dt.Rows[0]["Status"].ToString();
string EmpStatus = strempstatus.TrimEnd();

//Models.UserDetails detail = new Models.UserDetails();

if (EmpStatus == "Verified")
{
    //i want to create object which store below two variable value
    string EmployeeId = dt.Rows[0]["Id"].ToString();
    string DesignationId = dt.Rows[0]["D_Id"].ToString();

    //I want to stored object in below session
    HttpContext.Session.SetString("EmployeeData", EmployeeId);

    HttpContext.Session.SetInt32("EmployeeID", Convert.ToInt32(EmployeeId));
    //For Destroy Session
    //HttpContext.Session.Remove("EmployeeID");

    Int32? Saved = HttpContext.Session.GetInt32("EmployeeID");

    if (DesignationId == "1")
    {
        return RedirectToAction("Index", "AdminDashboard");
    }
    else
    {
        return RedirectToAction("Index", "UserDashboard");
    }
}

Answer 1

In your Startup.cs, under the Configure method, add the following line:

public void Configure(IApplicationBuilder app, IHostingEnvironment env)
{
app.UseSession();
}

And under the ConfigureServices method, add the following line:

public void ConfigureServices(IServiceCollection services)
{
  //Added for session state
  services.AddDistributedMemoryCache();

  services.AddSession(options =>
  {
  options.IdleTimeout = TimeSpan.FromMinutes(10);               
  });
}

In order to store complex objects in your session in .NET Core, follow the following steps:

Create a model class of your object type (in your case EmployeeDetails):

public class EmployeeDetails
{
    public string EmployeeId { get; set; }
    public string DesignationId { get; set; }
}

Then create a SessionExtension helper to set and retrieve your complex object as JSON:

public static class SessionExtensions
{
  public static void SetObjectAsJson(this ISession session, string key, object value)
   {
     session.SetString(key, JsonConvert.SerializeObject(value));
   }

   public static T GetObjectFromJson<T>(this ISession session, string key)
   {
     var value = session.GetString(key);
     return value == null ? default(T) : JsonConvert.DeserializeObject<T>(value);
   }
}

Then finally set the complex object in your session as:

var employee = new EmployeeDetails();
employee.EmployeeId = "1";
employee.DesignationId = "2";

HttpContext.Session.SetObjectAsJson("EmployeeDetails", employee);

To retrieve your complex object in your session:

var employeeDetails = HttpContext.Session.GetObjectFromJson<EmployeeDetails>("EmployeeDetails");
int employeeID = Convert.ToInt32(employeeDetails.EmployeeId);
int designationID= Convert.ToInt32(employeeDetails.DesignationId);