Not able get CheckOut files in SharePoint Object Model code.

Hi, I am writing a code to get some information related to files uploaded in SharePoint object model
That code getting information only for checked In files but those files which are in Checked Out mode and Checked Out by some other users id so those files information not coming.
Even when running code under “SPSecurity.RunWithElevatedPrivileges(delegate()”
But still not result for CheckOut files.
Below is the code sample to get file version size:
SPSecurity.RunWithElevatedPrivileges(delegate()
        {
            SPSite oSite = new SPSite("http://sitecollection/");
            SPWeb oWeb = oSite.OpenWeb();
            SPList mylist = oWeb.Lists[libname];
            long fileVersion = 0;
            dt = new DataTable();
            DataRow dtr;
            DataColumn dtc;
            foreach (SPListItem item in mylist.Items)
            {
                int iver = 0;
                fileVersion = fileVersion + item.File.Length;
                SPFileVersionCollection ver_coll = item.File.Versions;
                foreach (SPFileVersion item_ver in ver_coll)
                {
                    iver += item_ver.Size;
                }

                //listSize += item.File.Length;
                fileVersion += iver;
            }
            fileVersion = fileVersion / 1024;
            Label2.Text = fileVersion.ToString();
        });  

Kindly guide me.