This question has been asked time and time again. When the server sends HTML to a browser, these two rules are followed:
1. The browser must have requested the page via an HTTP GET or POST. (The server cannot change a page without the browser asking for it.)
2. The browser will only retrieve the HTML into the window that requested it.
There are only two ways to open a new window that I know about:
1. The <a> tag includes a target= property specifying a new window. (The HyperLink webcontrol is simply a way to generate the <a> tag. It includes a Target property.)
2. Use JavaScript such as a window.open or window.createPopup.
The <a> tag opens the new window before posting back and requests the new HTML from that new window.
The JavaScript technique requires that the original page already contains the JavaScript or when the server posts back, the browser is sent new HTML containing the new JavaScript to the original window. That means the original page's contents are replaced.
If you want to use the JavaScript technique to open a new window on post back:
1. Prepare the HTML necessary for the original page to draw.
2. Use Page.RegisterStartupScript() to call window.open. This will allow the new window to popup as the original window is loaded.
--- Peter Blum
Creator of Professional Validation And More Suite, Peter's Date Package, and Peter's Polling Package
www.PeterBlum.com