C# code to create Application Page using Visual Studio 2010

Steps Involved:

Creating Empty SharePoint Project:

• Open Visual Studio 2010. 
• Go to File => New => Project. 
• Select 2010 from the installed templates SharePoint and choose Empty SharePoint Project. 
• Name it as CustomApplicationPage.
  
  
  
  
• Click Add. 
• Enter the SharePoint server farm URL. 
• Select 'Deploy it as a Farm Solution". 
• Click Finish.

Adding Application Page:

• Right click the Solution Explorer and select Add a new item. 
• Select Application Page from the installed templates SharePoint and name it as CustomApplicationPage.
  
  
  
  
• Once you add the application page it will automatically create the Layouts Folder.
• In the solution explorer you could see Layouts -> CustomApplicationPage ->CustomApplicationPage.aspx.
• Once you deploy the solution the pages will be automatically placed in the 14 hive layouts folder.
• Open CustomApplicationPage.aspx from the solution explorer.
• In the "PlaceHolderMain" add one asp label control.
• And change the "PlaceHolderPageTitle" content to 'My Application Page" as shown in the following code.
  
  <%@ Assembly Name="$SharePoint.Project.AssemblyFullName$" %><%@ Import Namespace="Microsoft.SharePoint.ApplicationPages" %><%@ Register Tagprefix="SharePoint" Namespace="Microsoft.SharePoint.WebControls" Assembly="Microsoft.SharePoint, Version=14.0.0.0, Culture=neutral, PublicKeyToken=71e9bce111e9429c" %><%@ Register Tagprefix="Utilities" Namespace="Microsoft.SharePoint.Utilities" Assembly="Microsoft.SharePoint, Version=14.0.0.0, Culture=neutral, PublicKeyToken=71e9bce111e9429c" %><%@ Register Tagprefix="asp" Namespace="System.Web.UI" Assembly="System.Web.Extensions, Version=3.5.0.0, Culture=neutral, PublicKeyToken=31bf3856ad364e35" %><%@ Import Namespace="Microsoft.SharePoint" %><%@ Assembly Name="Microsoft.Web.CommandUI, Version=14.0.0.0, Culture=neutral, PublicKeyToken=71e9bce111e9429c" %><%@ Page Language="C#" AutoEventWireup="true" CodeBehind="CustomApplicationPage.aspx.cs" Inherits="CustomApplicationPage.Layouts.CustomApplicationPage.CustomApplicationPage" DynamicMasterPageFile="~masterurl/default.master" %>
  <asp:Content ID="PageHead" ContentPlaceHolderID="PlaceHolderAdditionalPageHead" runat="server"></asp:Content><asp:Content ID="Main" ContentPlaceHolderID="PlaceHolderMain" runat="server"></asp:Content><asp:Content ID="PageTitle" ContentPlaceHolderID="PlaceHolderPageTitle" runat="server">My Application Page  <asp:Label runat="server" Text="My Custom Page"></asp:Label>
  </asp:Content><asp:Content ID="PageTitleInTitleArea" ContentPlaceHolderID="PlaceHolderPageTitleInTitleArea" runat="server" >
  My Application Page</asp:Content>
• Build the solution. 
• Deploy the solution.

Testing:

• Go to the http://servername:2010/_layouts/CustomApplicationPage/ CustomApplicationPage.aspx.
• A new custom application page has been created in SharePoint 2010 as shown below.
  
  

Summary:

This article is mainly written to explain that a new template "Application Page" is available in the installed templates "SharePoint " -> "2010" and how to use that in visual studio 2010.

Refer: c-sharpcorner