How can I check parameter or session collection for a key?

How can I check if a parameter exists in the parameter collection or a key exists in
the Session collection?  

Currently I get an error when I do this and when there is no parameter
passed to the page: Request.Params["DBType"].

Samething I get when I do this with the Session object.

The error I get is this:
System.NullReferenceException: Object reference not set to an instance of an object.

Source Error:


Line 97:             private void Page_Load(object sender, System.EventArgs e)
Line 98:             {
Line 99:                   if(Request.QueryString["DSNType"].ToString() != "")
Line 100:                  {
Line 101:                              Response.Write("yes");
 
Thanks,

Andrzej
LVL 7
andw928Asked:
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smeggheadCommented:
put something like..

object MyObj=Request.QueryString["DSNType"];
if (MyObj!=null)
{
    Response.Write("yes");
}
0

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smeggheadCommented:
blimey, what do I have to do for an 'a' ?? do you want a tip ?

0
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