Display form URL of a list item or folder

The below code provides a generic way to form/build URL to the Display form of a list item or folder. This code makes use of the default dispform specified for the list through the property splist.Forms[PAGETYPE.PAGE_DISPLAYFORM].Url.

using (SPSite oSPSite=new SPSite("< site url > "))

            {

                using (SPWeb oSPWeb=oSPSite.OpenWeb())

                {

                    SPList oSPList = oSPWeb.Lists["ListName"];

                    SPListItem oSPListItem = oSPList.GetItemById(item_id);

                    string displayUrl;

                    string webUrl = oSPWeb.Url;

                    try

                    {

                        displayUrl = oSPListItem.ContentType.DisplayFormUrl;

                        if (string.IsNullOrEmpty(displayUrl))

                        {

                            displayUrl = oSPList.Forms[PAGETYPE.PAGE_DISPLAYFORM].Url;

                        }

                    }

                    catch (NullReferenceException)

                    {

                        displayUrl = oSPList.Forms[PAGETYPE.PAGE_DISPLAYFORM].Url;

                    }

                        

                    bool isLayouts = displayUrl.StartsWith("_layouts/", StringComparison.CurrentCultureIgnoreCase);

                    displayUrl = String.Format("{0}/{1}?ID={2}", webUrl, displayUrl, oSPListItem.ID);

                    if (isLayouts)

                        displayUrl = String.Format("{0}&List={1}", displayUrl, SPEncode.UrlEncode(oSPList.ID + ""));

                }

            }

Here, the displayUrl gives the link to the dispform of the item.