Paging and Sorting in ASP.NET GridView

Paging and Sorting in ASP.NET GridView

The ASP.NET GridView control is used to display the values of a data source in a table. ASP.NET provides the sorting feature in a GridView Control. The records displayed in a GridView control can be sorted in ascending or descending order.

In this article I will explain how to do paging and sorting in ASP.NET GridView.

The following is the step-by-step explanation.

Step1: Create a table in the database.

CREATE TABLE [dbo].[Teacher](
[TeacherId] [int] NULL,
[FirstName] [varchar](50) NULL,
[LastName] [varchar](50) NULL,
[Status] [varchar](50) NULL,
[Nationality] [varchar](50) NULL,
[Grade] [nchar](10) NULL
) ON [PRIMARY]

Step 2: Create a new ASP.NET web application and drag a GridView control in the Default.aspx design view. Set the property AllowSorting="true".

Step 3: Write the following in the page load event:

if (!Page.IsPostBack)
{
gvTeacher.DataSource = BindGridView();
gvTeacher.DataBind();
}

Step 4: The BindGridView() method populates the data in the GridView. Write the following method in the Default.aspx.cs file:

protected void gvTeacher_Sorting(object sender, GridViewSortEventArgs e)
{
string sortingDirection = string.Empty;
if (direction == SortDirection.Ascending)
{
direction = SortDirection.Descending;
sortingDirection = "Desc";

}
else
{
direction = SortDirection.Ascending;
sortingDirection = "Asc";

}
DataView sortedView = new DataView(BindGridView());
sortedView.Sort = e.SortExpression + " " + sortingDirection;
Session["SortedView"] = sortedView;
gvTeacher.DataSource = sortedView;
gvTeacher.DataBind();
}

Note: GridViewSortEventArgs is used to perform GridView sorting. There are two properties.

SortDirection specifies the direction to sort the GridView column, either by ascending or descending order.

Step 5: Select the GridView and double-click on PageIndexChanging .Write the following code:

protected void gvTeacher_PageIndexChanging(object sender, GridViewPageEventArgs e)
{
gvTeacher.PageIndex = e.NewPageIndex;
if (Session["SortedView"] != null)
{
gvTeacher.DataSource = Session["SortedView"];
gvTeacher.DataBind();
}
else
{
gvTeacher.DataSource = BindGridView();
gvTeacher.DataBind();
}
}

Step 6: Now maintain the SortDirection (Ascending or Descending) in ViewState by adding the following code.

public SortDirection direction
{
get
{
if (ViewState["directionState"] == null)
{
ViewState["directionState"] = SortDirection.Ascending;
}
return (SortDirection)ViewState["directionState"];
}
set
{
ViewState["directionState"] = value;
}
}

Step 7: The First Name is in ascending order as in the following:

The First Name in descending order as in the following: