ASP.NET MVC Extensions Methods

These are my extensions.

1. Not display dropdownlist if the Select list is null

   public static MvcHtmlString DropDownListNull(this HtmlHelper html,string Name,SelectList select,object htmlAttributes)
   {
   
   if (select == null)
   return MvcHtmlString.Empty;
   else
    return html.DropDownList(Name,select,htmlAttributes);
   
   }
   
   

2. Transform Enum to SelectList

   #region enum to list
           private static List<KeyValuePair<long,string>> FromEnum(this Type e)
           {
               List<KeyValuePair<long,string>> kvp = new List<KeyValuePair<long,string>>();
               foreach (var s in Enum.GetValues(e))
               {
                   kvp.Add(new KeyValuePair<long,string>((int)s,s.ToString()));
               }
               return kvp;
           }
           public static SelectList ToSelectList(this Type enumObj)
           {
   
               return new SelectList(enumObj.FromEnum(),"Key","Value");
   
           }
           #endregion
   

3. Transform Generic list into a SelectList

                 #region Generic List to SelectItem
           public static SelectList SelectFromList<TItem>(this List<TItem> values,
               Expression<Func<TItem,string>> key,Expression<Func<TItem,string>> value)
           {
               var Key = key.Compile();
               var Value = value.Compile();
               List<KeyValuePair<string,string>> kvp = new List<KeyValuePair<string,string>>(values.Count);
               values.ForEach(item =>
                   kvp.Add(new KeyValuePair<string,string>(Key.Invoke(item),Value.Invoke(item))));
   
               return new SelectList(kvp,"Key","Value");
   
           }
           #endregion
   
   

4. Display pager control

   #region paged list control
           //after http://geekswithblogs.net/nuri/archive/2009/08/05/mvc-paged-list.aspx
           /// <summary>
           /// Shows a pager control - Creates a list of links that jump to each page
           /// </summary>
           /// <param name="page">The ViewPage instance this method executes on.</param>
           /// <param name="pagedList">A PagedList instance containing the data for the paged control</param>
           /// <param name="controllerName">Name of the controller.</param>
           /// <param name="actionName">Name of the action on the controller.</param>
           public static void ShowPagerControl(this ViewPage page,BasePagedListImplementation pagedList,string formatUrl)
           {
               HtmlTextWriter writer = new HtmlTextWriter(page.Response.Output);
               if (writer != null)
               {
                   for (int pageNum = 1; pageNum <= pagedList.PageCount; pageNum++)
                   {
                       bool samepage=(pageNum == pagedList.PageNumber);
                       if (!samepage)
                       {
                           writer.AddAttribute(HtmlTextWriterAttribute.Href,string.Format(formatUrl,pageNum));
                           writer.AddAttribute(HtmlTextWriterAttribute.Alt,"Page " + pageNum);
                           writer.RenderBeginTag(HtmlTextWriterTag.A);
                       }
   
                       writer.AddAttribute(HtmlTextWriterAttribute.Class,
                                           pageNum == pagedList.PageNumber ?
                                                               "pageLinkCurrent" :
                                                               "pageLink");
   
                       writer.RenderBeginTag(HtmlTextWriterTag.Span);
                       writer.Write(pageNum);
                       writer.RenderEndTag();
   
                       if (!samepage)
                       {
                           writer.RenderEndTag();
                       }
                       writer.Write(" ");
                   }
   
                   writer.Write("(");
                   writer.Write(pagedList.TotalItemCount);
                   writer.Write(" items in all)");
               }
           }
   
           #endregion
   
   

Other extensions available that are good :

1. http://blog.wekeroad.com/blog/asp-net-mvc-list-helper-extension-method/
2. http://www.hanselman.com/blog/ASPNETMVCSessionAtMix08TDDAndMvcMockHelpers.aspx
3. http://helios.ca/2009/09/21/asp-net-mvc-extension-methods-of-urlhelper/
4. http://blog.donnfelker.com/2010/02/25/asp-net-mvc-tempdata-extension-methods/
5. http://inq.me/post/ASPNet-MVC-Extension-method-to-create-a-Security-Aware-HtmlActionLink.aspx

If you know more,please tell me