Hardik Shah [Guru]'s official Blog world: SharePoint 2007: Creating WebParts using ASP.Net Web User Controls

WebParts can be used as an add-on in MOSS (Microsoft Office SharePoint Server) 2007 or WSS (Windows SharePoint Services) 3.0. You can include ASP.Net functionality into SharePoint using Web Parts as well. Web Parts as developers know, does not have a front end when developed, we have to add controls to it dynamically for it to be displayed on SharePoint page. In such cases, to make the development effort easier and faster, ASP.Net Web User Controls (i.e. .ascx) can bear the Web Form layout. The Web Part can be made to use this Web User Control for displaying it on a SharePoint page. A matter of fact, developing, deploying and maintaining WebParts is one of the most tedious tasks for a SharePoint developer. Following steps will help you leverage a ASP.Net Web User Control with a Web Part.

Step 1: Creating the ASP.Net Web User Control

Create an ASP.Net web site and get your Web User Control (.ascx and .ascx.cs files) developed and tested as per your requirements. If you want your Web User Control to interact with SharePoint Object Model then you have to add references to the following 3 DLL’s:

• Microsoft.SharePoint
• Microsoft.SharePoint.Security
• Microsoft.SharePoint.intl

You can copy these three DLL’s from GAC using this link Here.

Keep the following points included in mind for certain cases:

◘ If you want to insert a custom JavaScript file specially for the ASP.Net User Control you can either use the <script></script> block in the .ascx file or use the following approach:

• Place an ASP.Net Placeholder in the section of the SharePoint Master page. Name it as per your convention.
• Use a Literal control (say 'Literal1') and add the <script src=" ... " type="text/javascript"></script> code for JavaScript or <link href=" ... " rel="Stylesheet" /> code for CSS to the ‘Literal1.Text’ attribute in the Page_Load event of the ASP.Net User Control.
• Access the Placeholder with the ID from the Page_Load event and add the Literal1 control to it.

◘ The JavaScript or CSS file so referenced in the Web User Control can either be a file visible in SharePoint 2007 Designer or in the ‘_layouts’ folder. Choosing the former option would be wiser.

◘ If you need to access a <ConnectionString> or <AppSetting> attribute from the Web User Control, make sure you make the required entry in the 'web.config' file.

Step 2: Placing the Web User Control in the '_layouts' folder

Place the ASP.Net Web User Control files (i.e. .ascx and .ascx.cs) in a folder created (name it wisely) in the ‘_layouts’ folder of your 12 hive where Microsoft SharePoint 2007 is installed. Place your JavaScript or CSS files here as well if you have chosen to reference them from your Web User Control here.

A majority of posts on the Internet will advice to keep the Web User Control files in the ‘_controltemplates’ virtual directory but believe me and my experience; I prefer the ‘_layouts’ virtual directory. In my example mentioned below, I have used a Web User Control named 'Photo_Gallery.ascx' placed in the folder 'PhotoGallery' in the '_layouts' folder.

Step 3: Creation of WebPart

Assuming you have your development environment ready, create a Web Part project in VS 2005/2008 using SharePoint Extensions for Visual Studio with the following code snippet:

 
using System;
using System.IO;
using System.Runtime.InteropServices;
using System.Web.UI;
using System.Web.UI.WebControls;
using System.Web.UI.WebControls.WebParts;
using System.Xml.Serialization;
 
using Microsoft.SharePoint;
using Microsoft.SharePoint.WebControls;
using Microsoft.SharePoint.WebPartPages;
 
namespace WP_PhotoGallery
{
 
    [Guid("c3417aa5-e282-42c8-a8b8-769d1f66af31")]
    public class SogetiPhotoGallery : System.Web.UI.WebControls.WebParts.WebPart
    {
 
        Control c;              //Variable for the Web Part Control
        String err;             //Will store the Exception
 
        public SogetiPhotoGallery()
        {
            /* Will allow to export the WebPart. Not mandatory. */
 
            this.ExportMode = WebPartExportMode.All;
        }
        
        protected override void Render(HtmlTextWriter writer)
        {
            
            /* SPSecurity.RunWithElevatedPrivileges block is required to run the Web Part with additional privilegs. 
             * This BLOCK is recommended to avoid user authentication/authorization issues. */
 
            SPSecurity.RunWithElevatedPrivileges(delegate()
            {
 
                try
                {
                    /* Render the Web User Control */
                    
                    c.RenderControl(writer);
                }
 
                catch (Exception e)
                {
                    /* Store the Exception in 'err' is any */
                    
                    writer.Write(e.Message + " : " + err);
                }
        
            });
            
        }
 
        protected override void CreateChildControls()
        {
 
            SPSecurity.RunWithElevatedPrivileges(delegate()
            {
                
                //Create all associated child controls necessary for display //
                
                base.CreateChildControls();
                
                try
                {
 
                    this.Controls.Clear();
                    
                    //Load the Web User Control (.ascx) and add it to the Page. //
 
                    c = this.Page.LoadControl("~/_layouts/PhotoGallery/Photo_Gallery.ascx");
                    this.Controls.Add(c);
                }
                    
                catch (Exception e)
                {
                    err = e.Message;
                }
                
            });
            
        }
 
    }
 
}

Step 4: Deployment of Web Part, populating it in Web Part Gallery and using a Web Part page to display the Web Part on a SharePoint page

Make sure you follow the required steps for deployment of Web Part. If you face any issues, please post it in the comments section.

As a reference for beginners, you can learn how to create, deploy and install Web Parts using this article Here.

You can download the source code Here: