Language

Animation Depending On a Condition (VB)

By Christian Wenz|

Download Code or Download PDF

The Animation control in the ASP.NET AJAX Control Toolkit is not just a control but a whole framework to add animations to a control. Whether an animation is run or not can also depend on a condition in form of some JavaScript code.

Overview

The Animation control in the ASP.NET AJAX Control Toolkit is not just a control but a whole framework to add animations to a control. Whether an animation is run or not can also depend on a condition in form of some JavaScript code.

Steps

First of all, include the ScriptManager in the page; then, the ASP.NET AJAX library is loaded, making it possible to use the Control Toolkit:

<asp:ScriptManager ID="asm" runat="server" />

The animation will be applied to a panel of text which looks like this:

<asp:Panel ID="panelShadow" runat="server" CssClass="panelClass"> ASP.NET AJAX is a free framework for quickly creating a new generation of more efficient, more interactive and highly-personalized Web experiences that work across all the most popular browsers.<br /> ASP.NET AJAX is a free framework for quickly creating a new generation of more efficient, more interactive and highly-personalized Web experiences that work across all the most popular browsers.<br /> ASP.NET AJAX is a free framework for quickly creating a new generation of more efficient, more interactive and highly-personalized Web experiences that work across all the most popular browsers.<br /> </asp:Panel>

In the associated CSS class for the panel, define a nice background color and also set a fixed width for the panel:

<style type="text/css"> .panelClass {background-color: lime; width: 300px;} </style>

Then, add the AnimationExtender to the page, providing an ID, the TargetControlID attribute and the obligatory runat="server":

<ajaxToolkit:AnimationExtender ID="ae" runat="server" TargetControlID="Panel1">

Within the <Animations> node, use <OnLoad> to run the animations once the page has been fully loaded. Instead of one of the regular animations, the <Condition> element comes into play. The JavaScript code provided as the value of the ConditionScript attribute is executed at runtime. If it evaluates to true, the animation is executed, otherwise not. The following markup provides two animations, each of them being executed in 50% of cases upon random. Since there may only be one animation within <OnLoad>, the two <Condition> animations are joined together using the <Sequence> element:

<ajaxToolkit:AnimationExtender ID="ae" runat="server" TargetControlID="Panel1"> <Animations> <OnLoad> <Sequence> <Condition ConditionScript="Math.random() 0.5"> <Resize Width="1000" Height="150" Unit="px" /> </Condition> <Condition ConditionScript="Math.random() 0.5"> <FadeOut Duration="1.5" Fps="24" /> </Condition> </Sequence> </OnLoad> </Animations> </ajaxToolkit:AnimationExtender>

Note that the less than sign (<) in the ConditionScript attribute must be escaped ( ). When you run this script, either no animation runs, or one of the two does, or both do.

The panel is fading out without resizing, so the second animation runs, the first one didn't (Click to view full-size image)

This article was originally created on June 2, 2008

Author Information

Christian Wenz

Christian Wenz – Christian Wenz is an author, trainer, and consultant. His main focus of working and writing is on web technologies and security. Christian has written or co-written over 100 books for various publishers. He works with both open source and closed source web technologies. This leads to the unusual situation that he has both been awarded a Microsoft MVP for ASP/ASP.NET and is listed in Zend's Who is Who of PHP. He is also listed in Mozilla's credits (about:credits) and is considered an expert in browser-agnostic JavaScript.