scrivere metodo generico per il paging

Question

Ho controller in cui verrà calcolata l'impaginazione. Ma ho 13 controller diversi. Quindi scrivere quel calcolo in ogni controller sarà noioso.

Questo è il metodo comoplete:

[Route("sort/{SortColumn}/{SortOrder?}", Name = "Sort-Product")] 
     [Route("page/{Page:int}/{SortColumn}/{SortOrder?}", Name = "Paging-Product")] 
     [Route("search/{SearchString}")] 
     [Route("index")] 
     public ActionResult Index(string searchString, string filter, string currentFilter, string sortColumn, string sortOrder, int? page) 
     { 
      IOrderedQueryable<Product> entities = (IOrderedQueryable<Product>)db.FilteredProducts; 

      if (searchString != null) page = 1; else searchString = currentFilter; 

      if (filter != null) { 
       string[] filters = filter.Split(new char[] { '.' }); 
       filter = ""; 

       // filter on form 
       if (filters.Length > 0 && !String.IsNullOrEmpty(filters[0])) { 
        FormLibraryEntry formEntry = FormLibraryController.GetFormLibraryEntry(filters[0], StateHelper.GetSchema()); 

        if (formEntry != null) { 
         entities = (IOrderedQueryable<Product>)entities.Where(
          s => s.FormName == formEntry.Id 
         ); 
         AddFixedNotification(String.Format(Resources.Entity.Environment.FilteredByFormMessage, formEntry.Name)); 
         filter += filters[0]; 
        } 
       } 

       // filter on design template 
       if (filters.Length > 1 && !String.IsNullOrEmpty(filters[1])) { 
        var designEntry = DesignTemplateController.GetTemplateLibraryEntry(filters[1], StateHelper.GetSchema()); 

        if (designEntry != null) { 
         entities = (IOrderedQueryable<Product>)entities.Where(
          s => s.TemplateName == designEntry.Id 
         ); 
         AddFixedNotification(String.Format(Resources.Entity.Environment.FilteredByDesignTemplateMessage, designEntry.Name)); 
         filter += "." + filters[1]; 
        } 

       } 
      } 

      if (!String.IsNullOrEmpty(searchString)) { 
       entities = (IOrderedQueryable<Product>)entities.Where(
         s => s.Name.ToUpper().Contains(searchString.ToUpper()) 
         || (!String.IsNullOrEmpty(s.FormName) && s.FormName.ToUpper().Contains(searchString.ToUpper())) 
         || (!String.IsNullOrEmpty(s.UrlName) && s.UrlName.ToUpper().Contains(searchString.ToUpper())) 
       ); 
       AddFixedNotification(String.Format(Resources.Entity.Environment.FilteredBySearchTermMessage, searchString)); 
      } 

      switch (sortColumn) { 
       case "id": 
        entities = (sortOrder == "desc") ? entities.OrderByDescending(s => s.Id) : entities.OrderBy(s => s.Id); 
        break; 
       case "name": 
        entities = (sortOrder == "desc") ? entities.OrderByDescending(s => s.Name) : entities.OrderBy(s => s.Name); 
        break; 
       case "enabled": 
        entities = (sortOrder == "desc") ? entities.OrderByDescending(s => s.IsEnabled) : entities.OrderBy(s => s.IsEnabled); 
        break; 
       case "formname": 
        entities = (sortOrder == "desc") ? entities.OrderByDescending(s => s.FormName) : entities.OrderBy(s => s.FormName); 
        break; 
       case "design": 
        entities = (sortOrder == "desc") ? entities.OrderByDescending(s => s.TemplateName) : entities.OrderBy(s => s.TemplateName); 
        break; 
       case "urlname": 
        entities = (sortOrder == "desc") ? entities.OrderByDescending(s => s.UrlName) : entities.OrderBy(s => s.UrlName); 
        break; 
       case "forms": 
        entities = (sortOrder == "desc") ? entities.OrderByDescending(s => s.SubmittedForms.Count()) : entities.OrderBy(s => s.SubmittedForms.Count()); 
        break; 
       case "modified": 
        entities = (sortOrder == "desc") ? entities.OrderByDescending(s => s.ModificationDate) : entities.OrderBy(s => s.ModificationDate); 
        break; 
       default: 
        sortColumn = "name"; 
        sortOrder = ""; 
        entities = (sortOrder == "desc") ? entities.OrderByDescending(s => s.Name) : entities.OrderBy(s => s.Name); 
        break; 
      } 

      ViewBag.SortColumn = sortColumn; 
      ViewBag.SortOrder = sortOrder == "desc" ? "desc" : ""; 
      ViewBag.SearchString = searchString; 
      ViewBag.Filter = filter; 

      int pageSize = StateHelper.GetPageSize(); 
      int pageNumber = StateHelper.HasPageSizeChanged ? 1 : (page ?? 1); 


      object selectionProduct = ModelHelper.GetSelectedModelId("Product"); 
      if (selectionProduct != null) { 
       IEnumerable<IEnumerable<Product>> pp = entities.Partition(pageSize); 
       int calculatedPage = 0; 
       bool found = false; 
       foreach (var item in pp) { 
        calculatedPage++; 
        IEnumerable<Product> inner = item as IEnumerable<Product>; 
        foreach (var product in inner) { 
         if (product.Id == (int)selectionProduct) { 
          found = true; 
          ViewBag.selectedRowProduct = product.Id; 
          break; 
         } 
        } 
        if (found) 
         break; 
       } 
       if (found) 
        pageNumber = calculatedPage; 

      } 

      return View(entities.ToPagedList(pageNumber, pageSize)); 
     } 

Ma questa è la parte di calcolo:

object selectionProduct = ModelHelper.GetSelectedModelId("Product"); 
      if (selectionProduct != null) { 
       IEnumerable<IEnumerable<Product>> pp = entities.Partition(pageSize); 
       int calculatedPage = 0; 
       bool found = false; 
       foreach (var item in pp) { 
        calculatedPage++; 
        IEnumerable<Product> inner = item as IEnumerable<Product>; 
        foreach (var product in inner) { 
         if (product.Id == (int)selectionProduct) { 
          found = true; 
          ViewBag.selectedRowProduct = product.Id; 
          break; 
         } 
        } 
        if (found) 
         break; 
       } 
       if (found) 
        pageNumber = calculatedPage; 

      } 

così cerco di costruire un metodo di supporto come questo:

public static bool FindPage(Type T, object modelId, IEnumerable<Type> entities, int pageSize, int calculatedPage, int? id) 
     { 
      if (modelId != null) { 
       calculatedPage = 0; 
       IEnumerable<IEnumerable<T>> pp = entities.Partition(pageSize); 
       int page = 0; 
       bool found = false; 
       foreach (var item in pp) { 
        page++; 
        IEnumerable<Type> inner = item as IEnumerable<Type>; 
        foreach (var product in inner) { 
         if (id == (int)modelId) { 
          found = true; 
          break; 
         } 
        } 
        if (found) 
         break; 
       } 
       if (found) 
        calculatedPage = page; 
       else 
        calculatedPage = 0; 

       return found; 
      } 
      return false; 
     } 

Ma ottengo questo errore:

The type or namespace name 'T' could not be found (are you missing a using directive or an assembly reference?) 

Grazie

Answer 1

Prova:

public static bool FindPage<T>(object modelId, IEnumerable<T> entities, int pageSize, int calculatedPage, int? id) 
    { 
     if (modelId != null) { 
      calculatedPage = 0; 
      IEnumerable<IEnumerable<T>> pp = entities.Partition(pageSize); 
      int page = 0; 
      bool found = false; 
      foreach (var item in pp) { 
       page++; 
       IEnumerable<T> inner = item as IEnumerable<T>; 
       foreach (var product in inner) { 
        if (id == (int)modelId) { 
         found = true; 
         break; 
        } 
       } 
       if (found) 
        break; 
      } 
      if (found) 
       calculatedPage = page; 
      else 
       calculatedPage = 0; 

      return found; 
     } 
     return false; 
    }