Create context menu item in SharePoint List

1. Wrote Custom Action such as

<CustomAction Id="EditContentTypeColumns"
        RegistrationType="ContentType"
        RegistrationId="0x010100B652F1B8BDCE44e8AB6560178C412708"
        Location="EditControlBlock"
        ImageUrl="/_layouts/images/edititem.gif"
        Sequence="303"
        Title="$Resources:SPPublicDemoTemplates,editContentType">
        <UrlAction Url="~site/_layouts/TemplateManagement/EditContentType.aspx?ListId={ListId}&amp;ItemId={ItemId}&amp;Source={SourceUrl}&amp;SiteUrl={SiteUrl}"/>
</CustomAction>

2. Type ContentTypeId that's item has this custom action.

3. EditContentType.aspx - my page in sharepoint

4. Code of Edit ContentType

using System;
using Microsoft.SharePoint;
using Microsoft.SharePoint.WebControls;

namespace Voodoo.SPPublicDemo.Templates
{
   public class EditContentType : LayoutsPageBase
    {
        protected override void OnLoad(EventArgs e)
        {
            base.OnLoad(e);
            using(SPSite site = new SPSite(Request.Params["SiteUrl"]))
            {
                SPWeb web = site.OpenWeb();
                SPList list = web.Lists[new Guid(Request.Params["ListId"])];
                SPListItem item = list.GetItemById(Convert.ToInt32(Request.Params["ItemId"]));
                SPContentType type = site.RootWeb.ContentTypes[item.ContentType.Name];
                Response.Redirect(String.Format("{0}/_layouts/ManageContentType.aspx?ctype={1}",
                    site.RootWeb.Url, type.Id.ToString()));
            }
        }
    }
}