Hi,

I want to create a custom dropdownlist with type-ahead functionality embedded in it.
So, I need to inherit the DropDownList class from the System.Web.UI.WebControls namespace.

I just want to get a kick-start to how I do this. I mean, I just need a small recipe to how I start. What kind of project do I start, what kind of template do I choose? Which methods do I HAVE to override to get the basic functionality of the dropdownlist?

Thanks!!

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I haven't failed, I've found 10,000 ways that don't work

1. The ASP.NET DropDownList creates the HTML tag <select>. The browser has a specific feature set for <select> and this imposes real limits.
2. The work you will do is client-side code using JavaScript. You will learn how to use DHTML (the document object model of Internet Explorer) and if you want Mozilla/FireFox support, DOM.
3. You will intercept keypress events using the onkeypress event handler available on <select>. Your code will look at event.keyCode to find out what key was pressed. Then you will take whatever action needed to consolidate the keystrokes into a string, search the <select> tag's <option> list to find a match then set its selectedIndex property.

Recommendation: ASP.NET has a rich variety of third party controls that are debugged and enhanced based on user feedback. Some are free. You can find many nice enhancements for your user interface, like menus, datepickers, validators, datagrids, and richtextboxes. There are several improved dropdownlists, usually characterized as "comboboxes". You can find them at this site's Control Gallery, www.123aspx.com, and www.411asp.net.

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--- Peter Blum
Creator of Professional Validation And More Suite, Peter's Date Package, and Peter's Polling Package
www.PeterBlum.com

Thanks, but I was more looking for a step-by-step guide to how I create a project and the .cs file in Visual Studio. I need to know what kind of project and what kind of .cs file I have to choose (what templates that is).

Furthermore, I need to know, if any, which methods in the class I have to override (from the inherited DropDownList class) to make my new custom control have the exact same functionality as the 'original' DropDownList.

Thanks!

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I haven't failed, I've found 10,000 ways that don't work

It sounds like you don't have the .net documentation for Visual Studio.net. Please be sure to have that. Its very easy to guess though:
File menu; New Project.
Pick your language
Web Control Library

To know what to override, you really need to read the .net documentation. Its a big project, not something we can (or should) teach here. I recommend the book "Developing ASP.NET Server Controls and Components" from Microsoft Press. But the .net docs is how I learned.

To know *how* to override a DropDownList, you must know how to develop object oriented code in your preferred language. You can easily just subclass without overriding a method and have a new control class name that has the identical functionality.

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--- Peter Blum
Creator of Professional Validation And More Suite, Peter's Date Package, and Peter's Polling Package
www.PeterBlum.com

Allright, thanks! You gave me the small push that I needed!

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I haven't failed, I've found 10,000 ways that don't work