Hi,
I am getting the following exception
'Element 'UpdatePanel' is not a known element. This can occur if there is a compilation error in the Web site' as warning.I want to clear this.I searched web in that i found 'change tagPrefix in web.config' to solve this.This is due to the use of Ajax.But in my web.config the tagPrefix found to be correct but still i am getting warning over this.Can anyone suggest the best way to solve this one?....

Hi,
I got the solution for this.Actually the 'Element 'UpdatePanel' is not a known element.This can occur if there is a compilation error in the Web site' is not an error.This is because the loss of the html intellisense in C#.You can eliminate the errors and warnings caused by this by opening the master page.

Step1:Open the page that contains update panel.It lists you error and warnings in errorlist.
Step 2:Open the master page.This will give you intellisense
Step 3:Now see the error list.No more errors and warnings will be there.The red line over update panel will be eliminated.

hi


the actual reason for this error is missing of script Manager tag which was used in ajax concepts.

i think u would have placed the script manager tag in your master page thats why the error goes after u open your master page.

you can avoid this error by also placing your script manager tag where ever necessary alone. It means in the page where u use your update panel tag.

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''''''Rajesh''''''
Ants. . . . . . Like me

Hi,
Another way to solve this error is,

Web.Config
<controls>
<add tagPrefix="asp" namespace="System.Web.UI" assembly="System.Web.Extensions, Version=1.0.61025.0, Culture=neutral, PublicKeyToken=31bf3856ad364e35"/>
</controls>
i) Change the tagprefix='asp' in web.config to tagprefix="ajaxToolkit" or whatever u want.
<controls>
<add tagPrefix="ajaxToolkit" namespace="System.Web.UI" assembly="System.Web.Extensions, Version=1.0.61025.0, Culture=neutral, PublicKeyToken=31bf3856ad364e35"/>
</controls>
ii)Then you have to change <asp:UpdatePanel> to <ajaxToolkit:UpdatePanel>, this removes the redline.But you will get require permissions error.
iii)To avoid 'requirePermission' error ,In the site master page define the register tag used for ajaxControlToolkit.
iv)In Master page change <asp:ScriptManager> to <ajaxToolkit:ScriptManager>
v)Now the errors and warnings in errorlist is completely avoided.