Hi Jay,
You actually don't address the loginform directly, but your request will be interecepted by the loginform, if you have the authentication set up correctly. Inside the login form, in the Load event, you can get to all the query parameters via the Arguments collection.
Remember that the link will have to be a post.mainform.wgx?par1=x&par2=y etc., where "mainform" is your mainform in this case.
This C# code in the Loginform's load event, will dump all the query parameters:
for (int i = 0; i < Context.Arguments.Count; i++)
{
textBox1.Text += Context.Arguments.GetKey(i).ToString()
+ " = "
+ Context.Arguments.Get(i).ToString() + Environment.NewLine;
}
Hope this helps,
Palli