Error: ASP.NET Ajax client-side framework failed to load. OR 'Sys' is undefined. in VS 2008
Cause:
I got this error very first time when I tried to use AJAX ScriptManager object using VS2008.
I was tring to registred script using ScriptManager like below
protected void Button1_Click(object sender, EventArgs e)
{
ScriptManager.RegisterStartupScript(
this,this.GetType(),"script","alert('Hi');",true);
}
Solution:
I found there are two way to solve this error
1) You need to add httpHandlers into the web.config below "compilation" tag
Code:
<!--Ajax -->
<httpHandlers>
<remove verb="*" path="*.asmx"/>
<add verb="*" path="*.asmx" validate="false" type="System.Web.Script.Services.ScriptHandlerFactory, System.Web.Extensions,
Version=1.0.61025.0, Culture=neutral, PublicKeyToken=31bf3856ad364e35"/>
<add verb="GET" path="ScriptResource.axd" type="System.Web.Handlers.ScriptResourceHandler" validate="false"/>
</httpHandlers>
<compilation debug="true">
2) You can solve this error by using RegisterAsyncPostBackControl method
Using beolw code button control will not have any page refresh like a client control.
Code:
protected void Page_Load(object sender, EventArgs e)
{
// register the Button1 control as one that can cause partial postbacks.
ScriptManager1.RegisterAsyncPostBackControl(Button1);
}
Note: I may not get this error in latest version/patch of VS2008.
