Friday, September 26, 2008

Color Picker ASP.NET AJAX extender control

I was looking for a client-side color picker control and found it extremely difficult to find something that would satisfy to my requirements. I have found plenty of pure JavaScript controls written with various levels of proficiency and there was even one ASP.NET color-picker control that I almost liked but still my major requirement was not satisfied: I was looking for AJAX .NET Extender control - easy to use and based on a solid and proven platform.

So, I have researched what other color picker controls do and decided to write the one myself that I would base on Microsoft AJAX .NET platform. After some considerations I've decided to go even further and build an AJAX Control Toolkit Extender control.

As an example I took an AJAX Control Toolkit Calendar extender and in my Color Picker extender control I also internally used another AJAX Control Toolkit control: Popup extender.

Now, what are the advantages of implementing a client control as an ASP.NET AJAX extender?

  1. You use ASP.NET page mark-up to render the control content to the browser.
  2. No need to manually inject JavaScript, HTML and other resources.
  3. You develop JavaScript code in a standalone file leveraging ASP.NET AJAX framework and Visual Studio intellisense abilities.
  4. JavaScript per se is very well structured, easy to read and debug.
  5. Many of the hassles of JavaScript client coding such as cross-browser compatibility, event handling, asynchronous calls are taken care of by ASP.NET AJAX framework.

So, I have spent a few days coding the control and finally it's out there. I have created a Codeplex project for it so if you are interested just go there and download the control and a Demo Web site.

Now, just a few more words about the extender. First, this is how it looks:

Second, it's extremely easy to use. The extender attaches to an ASP.NET TextBox server control and to an optional button that can open a popup window and an element that samples a selected color in the background. User selects a color by clicking on a colored area. Below is a code example of using an extender on an ASP.NET page.

<asp:TextBox ID="TextBox1" runat="server" 
       Columns="7" MaxLength="7"></asp:TextBox>
  <asp:ImageButton ID="ImageButton1" runat="server" 
       ImageUrl="~/Images/icon_colorpicker.gif" />
  <cdt:ColorPickerExtender ID="cpe" runat="server" 
       PopupButtonID="ImageButton1" />

Feel free to download the extender from the Codeplex, try it and post any comments or suggestions on the Codeplex project page.

Update 2020

Recently, I've visited the old and now archived CodePlex page for the ColorPickerExtender (https://archive.codeplex.com/?p=cpe) and found out that back in the day Microsoft had included that control on the official ASP.NET site (https://docs.microsoft.com/en-us/aspnet/web-forms/overview/ajax-control-toolkit/colorpicker/using-the-colorpicker-control-extender-cs). What a nice thing! Encouraged by this finding I've decided to resurrect the CPE and port it over to Angular, which is currently my favourite client-side framework. I will be introducing a new project on Git some time at the end of 2020, so stay sharp!

Friday, September 19, 2008

Axialis IconWorkshop™ Lite for VS 2008

It's been a little buzz around this free VS2008 plug-in but it really is true and there is a free version of the Axialis IconWorkshop for VS2008. If you want to download and install it please use the direct link because you won't be able to find this page on the Axialis web site. Though to be honest its functionality is not anyhow better then Paint.Net which is also free but fully-functional. Besides being called a VS plug-in it opens up in a separate window. But see for yourself.

Monday, September 15, 2008

Working with VEColor class of VirtualEarth SDK

If you ever wanted to set a color for a custom VEShape object of type polyline or polygon than you must be familiar with the VEColor class that is used to represent a color in VirtualEarth SDK.

I am sure there are reasons behind of the design of the VEColor class, but for those who are used to a standard Web color representation in a form of 6-digit hexadecimal number it's kind of weird to provide 3 integer number in order to construct a color.

So I was in a search for some convenient ways of converting between VEColor and standard Web color and first place I looked through was of course the VirtualEarth Map control because I thought that the VE developers themselves would need a way to perform the same exercise. No surprise there is a couple of non-documented VE objects to support such conversion technique.

Here is a code example of using those objects:

// Create a convertor class
var converter = new VEHexStringToColor();
// Converter returns an instance of a VEColor class
// Transparency value is always set to 1.0
var veColor = converter.Convert("aabbcc");
// Adjust transparency value
veColor.A = 0.7;
// Convert VEColor to a string with a leading '#'
var webColor = VEColorToHexString(veColor);alert(webColor);

Both objects are available on the page after you reference a VE Map control v6.1. Of course there is no guarantee of any support of those objects in any future versions of the VE Map control so use it at your own risk and have fun.