GridView Pagination issue when dynamically added….!
Posted by Abin Jaik Antony on March 26, 2010
Hello ASP.NET Developers… Today I came across a small issue which killed large amount of my development time. The issue was a little tricky between the lines of code. I have an ASP.NET gridview which is dynamically (on the fly) created on my page. When I am inserting 2 lines of code just for allowing the gridview pagination, code breaks at runtime giving a NullReferenceException .
Cause of the issue : i was adding the dynamically created gridview(object) into page’s control collection after the databinding. This works fine if there is no pagination code added. But if there is code which allows pagination for the dynamically added gridview, this gridview should be added to the page’s control collection before the databinding.
Please see the below mentioned code blocks for the difference.
This piece of code will give the Null Reference Exception:
GridView gvDepartment = new GridView (); gvDepartment.ID = "gvDepartment"; gvDepartment.AllowPaging = true; gvDepartment.PageSize = 4; gvDepartment.DataSource = GetDepartmentRows (); gvDepartment.DataBind (); this.form1.Controls.Add ( gvDepartment );
This is the perfect code:
GridView gvDepartment = new GridView (); gvDepartment.ID = "gvDepartment"; gvDepartment.AllowPaging = true; gvDepartment.PageSize = 4; /* Need to add gridview into controls collection before databind,if there is pagination */ this.form1.Controls.Add ( gvDepartment ); gvDepartment.DataSource = GetDepartmentRows (); gvDepartment.DataBind ();
NB: Obviously PageIndexChanging Event handling is needed. But this post is about the exception thrown while dynamically adding gridview. So the readers please keep in mind to add pageindexchanging event should be handled.
I hope this post helped you or given a nice thought. Thanks for reading.Please comment if you feel any issues on the same.