Custom DataGrid With Next, Previous, First, Last, and Numeric Paging

Introduction

In one of my web projects, the requirement was such that the pager should have numeric paging as well as links for previous, next, first, and last pages. The DataGrid did not directly support this type of layout; that's why I have developed my custom DataGrid that can be used throughout.

Background

The basic idea is very simple: Create a custom control that is inherited by DataGrid and overrides the ItemCreated event. Here, you have to understand how DataGrid renders controls for Pager. The DataGrid renders controls like this (LinkButton or label) (Literal control) (LinkButton or label) ... and so on. Literals are used to put space between controls and Labels are used to show disabled pager links.

You can calculate the total pages from the items in the pager cell by using this formula:

TotalPages = (e.Item.Cells[0].Controls.Count /2) +1

This count is useful for assigning the command argument for ImageButton for the last page. The onItemCreated event is written below.

Using the Code

Just add the MycustomDG.dll in the VS .NET toolbar or add a reference to MycustomDG.dll. Assign the following properties:

  • ShowPreviousAndNextImage
  • ShowFirstAndLastImage
  • ImageFirst
  • ImageLast
  • ImagePrevious
  • ImageNext

Code for OnItemCreated

protected override void OnItemCreated(DataGridItemEventArgs e)
{
   if(e.Item.ItemType == ListItemType.Pager)
   {
      int _TotalCount  = e.Item.Cells[0].Controls.Count;
      int _TotalPagers = (_TotalCount/ 2) +1;
      int _CurrentPage = this.CurrentPageIndex;
      if(_TotalCount > 1)
      {
         LinkButton btnPrev  = new LinkButton();
         LinkButton btnNext  = new LinkButton();
         LinkButton btnFirst = new LinkButton();
         LinkButton btnLast  = new LinkButton();

         if(_Show_Prev_Next_Image)
         {
            #region Next & previous
            if(_CurrentPage +1 <= _TotalPagers )
            {    // Enable Next
               string sImgNext ="<img alt='Next' border='0'
                                 src='"+ _ImgNext+"'>";
               btnNext.Text = sImgNext;
               btnNext.CommandArgument = (_CurrentPage+2).ToString();
               btnNext.CommandName = "Page";
               btnNext.Enabled = true;
            }
            else
            {    // disable next
               string sImgNext ="<img alt='Next' border='0'
                                 src='"+ _ImgNext+"'>";
               btnNext.Text = sImgNext;
               btnNext.Enabled = false;
            }

            if(_CurrentPage > 0)
            {    // enable Previous
               string sImgPre ="<img alt='Previous' border='0'
                                src='"+ _ImgPrev+"'>";
               btnPrev.Text = sImgPre;
               btnPrev.CommandName = "Page";
               btnPrev.CommandArgument = (_CurrentPage).ToString();
               btnPrev.Enabled = true;
            }
            else
            {    // disable previous
               string sImgPre ="<img alt='Previous' border='0'
                                src='"+ _ImgPrev+"'>";
               btnPrev.Text = sImgPre;
               btnPrev.Enabled = false;
            }
            #endregion
         }


         if(_Show_First_Last_Image)
         {
            #region First & last
            if(e.Item.Cells[0].Controls[_TotalCount -1].GetType() !=
               typeof(System.Web.UI.WebControls.Label))
            {
               string sImgNext ="<img alt='Last' border='0'
                                 src='"+ _ImageLast+"'>";
               btnLast.CommandArgument = _TotalPagers.ToString();
               btnLast.CommandName = "Page";
               btnLast.Text = sImgNext;
               btnLast.Enabled = true;
            }
            else
            {
               string sImgNext ="<img alt='Last' border='0'
                                 src='"+ _ImageLast+"'>";
               btnLast.Text = sImgNext;
               btnLast.Enabled = false;
            }


            if(e.Item.Cells[0].Controls[0].GetType() !=
               typeof(System.Web.UI.WebControls.Label))
            {
               string sImgPre ="<img alt='First' border='0'
                                src='"+ _ImageFirst+"'>";
               btnFirst.CommandArgument = "1";
               btnFirst.CommandName = "Page";
               btnFirst.Text = sImgPre;
               btnFirst.Enabled = true;
            }
            else
            {
               string sImgPre ="<img alt='First' border='0'
                                src='"+ _ImageFirst+"'>";
               btnFirst.Text = sImgPre;
               btnFirst.Enabled = false;
            }
            #endregion
         }


         e.Item.Cells[0].Controls.AddAt(0,btnPrev);
         e.Item.Cells[0].Controls.AddAt(e.Item.Cells[0].Controls.Count,
                                        btnNext);
         // Add These 2 Images at the First and last Position
         e.Item.Cells[0].Controls.AddAt(0,btnFirst);
         e.Item.Cells[0].Controls.AddAt(e.Item.Cells[0].Controls.Count,
                                        btnLast);
      }
   }
   base.OnItemCreated (e);
}


About the Author

saifi hasan

I have been in development Web Application, Web Sevices for last 3 yrs.Currently working with TCS India

Downloads

Comments

Leave a Comment
  • Your email address will not be published. All fields are required.

Top White Papers and Webcasts

  • U.S. companies are desperately trying to recruit and hire skilled software engineers and developers, but there's simply not enough quality talent to go around. In response, companies often resort to inferior solutions -- hiring substandard developers and engineers, recruiting talent on a part-time or temporary basis, poaching people from competitors, or burdening an already stressed IT staff for more of their labor. Fortunately, there's a better solution. Read this white paper to learn the business value of …

  • Lenovo recommends Windows 8 Pro. "I dropped my laptop getting out of the taxi." This probably sounds familiar to most IT professionals. If your employees are traveling, you know their devices are in for a rough go. Whether it's a trip to the conference room or a convention out of town, any time equipment leaves a user's desk it is at risk of being put into harm's way. Stay connected at all times, whether at the office or on the go, with agile, durable, and flexible devices like the Lenovo® …

Most Popular Programming Stories

More for Developers

RSS Feeds

Thanks for your registration, follow us on our social networks to keep up-to-date