GridView is one of the most popular controls to display data in a tabular format. But for better analysis, it requires to show the data in some summarized form like Group, Pivot, Graphs, Charts, etc. This articles presents a simplified way to group your data with the appropriate aggregate functions so that you can enhance your reports with a great ease. Facility to customize the group header and footer in your own way becomes the essential part when you are grouping your data. The control shown in the article has taken care of this requirement as well.
Below is a screenshot of grouped data in a
GroupGridView control is a custom control derived from
GridView. The primary purpose for this control is to implement the grouping feature in the
GridView. To accommodate the customized group header and footer,
GroupContainer class is created which is derived from
INamingContainer. This class is provided with various aggregate functions that can be applied to each group in your
GridView. The useful methods in
Average(ColumnName): Returns the average of the data present in the group for the given column
Count(ColumnName): Returns the total number of rows present in the group for the given column
First(ColumnName): Returns the first element of the given column in the group
Last(ColumnName): Returns the last element of the given column in the group
Max(ColumnName): Returns the maximum value of the data present in the group for the given column
Min(ColumnName): Returns the minimum value of the data present in the group for the given column
Sum(ColumnName): Returns the sum of data present in the group for the given column
GetValue(DataColumn, PropertyColumn, MatchingValue): Returns the value of the
PropertyColumn is equal to the
How It Works
The logic behind grouping the data in
GridView can be divided into three parts:
- Instantiate the HeaderTemplate Template: To do this, custom control has been created with two exposed properties:
GroupFooterTemplate. This Template needs to be instantiated for each group present in your
DataSource. This has been done by overriding the
PrepareControlHierarchy() method of
- Recognize Group and Render Group Header at proper place: To recognize the group, I have overridden
OnRowCreated() method of the
GridView and added "
group" attribute and its value to each row of the table. To align
Footer at proper place, JQuery has been used.
- Providing Hide/Show functionality to the group: The hide/show functionality to each group has been provided using JQuery. Please have a look over
RenderClientSideGroup() method to understand the JQuery code used to
FadeOut the Group(s). You don't need to learn JQuery to use this control.
Using the Code
Using the code is simple. The control is provided with two additional Template Containers:
GroupFooterTemplate. Both of these Template containers provide you the facility to write your own custom HTML code and use Aggregation logic to format your
Footer of the each group of
Below is the sample aspx markup which you can write to make this control work (don't forget to include JQuery file in your code):
//Copy the GroupGridViewCtrl.dll to your bin directory. Add reference.//
<%@ Register Assembly="GroupGridViewCtrl"
Namespace="GroupGridViewCtrl" TagPrefix="gsoft" %>
<gsoft:GroupGridView AllowGrouping="true" GroupColumnName="Year"
<td style="width:50%; font-weight:bold;">
<%# Container.GroupColumnName + ": " +
Container.GroupColumnData.ToString() %> </td>
<td style="width:50%;">Total Students:
<%# Container.Count("Name") %></td>
<td>Average Marks: <%# Math.Round((decimal)
Container.Average("Marks"), 2) %></td>
<td>Highest: <%# Container.Max("Marks") %></td>
<td colspan="2">Topper: <%# Container.GetValue
("Name", "Marks", Container.Max("Marks").ToString())%></td>
To make this control work, don't forget to set
AllowGrouping property to true. Moreover,
GroupColumnName property must be set to the correct value.
Based on various feedback/emails of the readers, I have included some more options in this version of GroupGridView Control. Some of them are as follows:
- DefaultState This control now has a property called DefaultState which determines whether to keep the grouped data collapsed or expanded by default.
- Multiple Grids in a Page: The current version of GroupGridView control now allows you to have multiple GroupGridView controls in a page working simultaneously.
- EmptyGroupFooter: When the group footer is not needed, you may now simply omit the
- Paging: You may implement your normal paging behaviour of the GridView in this control, but, you need to understand that this control will group the data of the current page only. If you are implementing paging, you must watch and understand the behavior of aggregate functions used in Group Headers and Footers.
Points of Interest
Along with grouping the data in
GridView, the sample will also provide the following things to the beginners:
- How to create a custom control
- How to create and use Template/Container Control
- How to read data from Excel Sheet
- How to use Linq to filter DataTable data
- First version release: October 05, 2010
- Version 1.1: June 09, 2013
- Version 1.2: June 12, 2013: Added client side options.