ASP.NET Cookbook

1.11. Sorting Data Within a DataGrid

Problem

You are displaying a table of data and you want to let the user sort the data in a DataGrid by clicking on its column headers.

Solution

Enable the DataGrid control’s sorting features, and create a routine that binds the appropriate data to the control when it is initially displayed and whenever the user clicks a column header.

In the .aspx file, enable the DataGrid control’s sorting features.

In the code-behind class for the page, use the .NET language of your choice to:

1. Create a data-binding method (bindData in our example) that performs the actual sorting based on the value of a sortExpression parameter and binds a dataset to the DataGrid (this parameter is used in the ORDER BY clause of the SQL statement).

2. Call the data-binding method from the Page_Load method (to support the initial display of the grid) and from the event that is fired when the user clicks on a column header (the dgBooks_SortCommand event in our example).

Figure 1-12 shows the appearance of a typical DataGrid sorted by title, the information in the first column. Example 1-30 through Example 1-32 show the .aspx and code-behind files for an example application that produces this result.

Figure 1-12. DataGrid with column sorting output

Discussion

The DataGrid control provides the basic plumbing required to support sorting. It will generate the links for the column headers that ...