Building a DataGrid Helper Control for ASP.NET 1.x: Part 3
page 1 of 6
Published: 09 Jul 2004
Unedited - Community Contributed
Abstract
In the first two parts of this series, we built a DataGrid helper control that can be used to develop a data access page with sorting, paging, deleting, and updating capabilities without writing a single line of code. In this part, we will discuss how to customize DataGrid columns using custom columns.
by Li Chen
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Introduction

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In Part 1 and Part 2 of this series, we successfully built the DataGridHelper control that can be used to develop a data access page with sorting, paging, deleting, and updating capabilities without writing a single line of code.  I have had too much fun to stop now. In Part 3, we will address another limitation of DataGrid and DataGridHelper control--custom columns.

In ASP.NET 1.x, the easiest way to create custom column is by using the TemplateColumn. The TemplateColumn supports one-way databinding to display the data. The update code is not exactly pretty, as seen in a Microsoft QuickStart sample, because we have to find the control from the controls collection of the table cell and extract the value from the control. The up-coming ASP.NET 2.0 will support two-way binding in GridView templates.  For ASP.NET 1.x, Marcie Robillard’s MSDN article discussed an excellent idea of custom columns. The code related to the column is packaged in the custom column class instead of an aspx page, making it reusable. Although it takes some up-front cost to develop, custom columns are easier to use than TemplateColumn. The Metabuilders site has a few great custom columns. In this article, we will extend the idea further by giving the custom column class the responsibility to extract user input. We will also extend the DataGridHelper control to work with custom columns.

We will start by creating the necessary interface for the DataGridHelper control to work with custom columns. We will then build two custom columns that support such an interface. We will also discuss how to extend an existing custom column so we can use the DataGridHelper control with any custom column. We will finally demonstrate how to use the custom columns and conclude this article.

Let's define the interface first.


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User Comments

Title: how to insert   
Name: eyal
Date: 6/9/2005 4:02:12 AM
Comment:
i wont to insert to grid in a way that the colomn will open in a visual stae in the grid mach like the edit command if you can help me
thenks
Title: Building a DataGrid Helper Control for ASP.NET 1.x: Part 3   
Name: greg
Date: 4/30/2005 12:07:57 PM
Comment:
he control is very cool.
I have a question regarding the DataGridHelper control:
1. why do we need a DataGridHelperconnector component? the web component is disappeared in asp.net 2.0

2. can we set the properties dataAdapter, datagrid to browsable instead of using the connector? so that we can set these properties at design time.

I'm lokking forward to your answer, Thanks
Title: Re: Small bug   
Name: Li Chen
Date: 12/22/2004 12:12:44 PM
Comment:
I would like to thank Robert for pointing out the bug in part 2 of the article. The bug was discovered during the writing of the part 3 of this series and fixed. Readers are urged to use the code from part 3.
Title: Small bug   
Name: Robert Storrs
Date: 12/1/2004 2:34:39 PM
Comment:
Great Article. One of the best I have read in some time.

I did find a small bug and added the following line as line 134 in the DataGridHelperConnector.cs (in version 2)

134 if(_dataGridHelper.DataGrid != _dataGrid)
_dataGridHelper.DataGrid = _dataGrid;

Without this check, the program creates two event handlers for the SortCommand. This results in the new sort order always being DESC. It also caused multiple reloading of the grid.
Title: Everybody speaks C#   
Name: Shain
Date: 9/14/2004 9:06:50 PM
Comment:
Any computer science program should know the basics of languages similiar to Java, C++, C, or the like. It is not very hard to convert C# code to VB code and since this article really explores Data Structures & Algorithms approaches it is pretty easy to convert. You should study this article, and if you need VB, try to write the code yourself. There is probably an advantage to having this as C# code -- although the CLR may not care.
Title: love it   
Name: ben
Date: 9/14/2004 7:09:11 AM
Comment:
love it
Title: Building a DataGrid Helper Control for ASP.NET 1.x: Part 3   
Name: Peter Ho
Date: 9/12/2004 12:29:05 AM
Comment:
A great series of articles, Mr. Chen. Thanks!
Title: Building a DataGrid Helper Control for ASP.NET 1.x: Part 3   
Name: T. freeman
Date: 8/16/2004 11:07:09 AM
Comment:
Excellent article - well written, good detail. Thanks!
Title: Building a DataGrid Helper Control for ASP.NET 1.x: Part 3   
Name: Li Chen
Date: 7/20/2004 12:53:03 PM
Comment:
Sam,

The download does include the VB version of the DataGridHelperTest project.

Li
Title: Building a DataGrid Helper Control for ASP.NET 1.x: Part 3   
Name: Sam Richardson
Date: 7/20/2004 9:27:49 AM
Comment:
It would be even better if there was some vb.net code to go with it - not everyone speaks C#.

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