sharepoint 2010 list groups from event receiver to form or dialog box?

Question

How can I get a list of groups in a form or dialog box to select one or more groups, and then assign permissions to the document? Here in this code:

using System;
using System.Security.Permissions;
using Microsoft.SharePoint;
using Microsoft.SharePoint.Security;
using Microsoft.SharePoint.Utilities;
using Microsoft.SharePoint.Workflow;

namespace ItemAdded.EventReceiver1
{
    /// <summary>
    /// События элемента списка
    /// </summary>
    public class EventReceiver1 : SPItemEventReceiver
    {
       /// <summary>
       /// Добавлен элемент.
       /// </summary>
       public override void ItemAdded(SPItemEventProperties properties)
       {
           base.ItemAdded(properties);
           SPSite site = new SPSite(properties.WebUrl);

           SPWeb web = site.OpenWeb();
           SPDocumentLibrary docLib = (SPDocumentLibrary)web.Lists["Test_Doc_Lib"];
           SPGroup oGroup = web.SiteGroups["Програмисты"];
           var groups2 = new SPFieldUserValueCollection();
           groups2.Add(new SPFieldUserValue(web, oGroup.ID, oGroup.Name));
           SPUser currentUser = web.CurrentUser;
           SPGroupCollection asd = currentUser.Groups;
           var groups = new SPFieldUserValueCollection();
           foreach (SPGroup group in asd)
           {

               //foreach (SPFieldUserValue group in groups)
               groups.Add(new SPFieldUserValue(web, group.ID, group.Name));

           }
           EventFiringEnabled = false;
           // properties.ListItem["ответственный"] = oGroup;
           properties.ListItem["ответственный"] = groups + ";#" + groups2;
           properties.ListItem.Update();
           EventFiringEnabled = true;

           var userValues = (SPFieldUserValueCollection)properties.ListItem["ответственный"];
           foreach (SPFieldUserValue userValue in userValues)
           {
               var user = properties.Web.SiteGroups.GetByID(userValue.LookupId);
               SetSPListItemUserPermissions(properties.ListItem, user, SPRoleType.Contributor);
           }

       }

       public void SetSPListItemUserPermissions(SPListItem listItem, SPPrincipal Principal, SPRoleType roleType)
       {
           //Break role inheritance
           if (!listItem.HasUniqueRoleAssignments)
               listItem.ResetRoleInheritance();
           EventFiringEnabled = false;
           listItem.Update();
           listItem.BreakRoleInheritance(false);
           listItem.Update();

           //Create new role
           var roleDefinition = listItem.Web.RoleDefinitions.GetByType(roleType);
           var roleAssignment = new SPRoleAssignment(Principal);
           roleAssignment.RoleDefinitionBindings.Add(roleDefinition);

           //Assign new role
           listItem.RoleAssignments.Add(roleAssignment);
           listItem.Update();
           EventFiringEnabled = true;
       }
    }
}