Use the SetNoStore method of the HttpCachePolicy class to direct the client not to store the responses in its history. See http://msdn.microsoft.com/en-us/library/system.web.httpcachepolicy.setnostore.aspx
In which event are the controls fully loaded?
On Load event. (http://msdn.microsoft.com/en-us/library/system.web.ui.page(v=vs.100).aspx)
The Page object calls the OnLoad method on the Page object, and then recursively does the same for each child control until the page and all controls are loaded. The Load event of individual controls occurs after the Load event of the page.
Use the OnLoad event method to set properties in controls and to establish database connections.
How we can force all the validation controls to run?
Using Page.Validate() method to instructs any validation controls included on the page to validate their assigned information.
Read more at http://msdn.microsoft.com/en-us/library/0ke7bxeh.aspx
What is .ASCX file?
.ascx file is a user control file.
Read more at http://msdn.microsoft.com/en-us/library/26db8ysc(v=vs.71).aspx