Is possible to write a query like below using LINQ? Is giving me the error
"cannot be applied to operands of type double and string"
key = Request.QueryString["key"];
var query = from p in db.VERSIONs where p.vr_key == key select p;
3 Answers
try this:
Double key = Convert.ToDouble(Request.QueryString["key"]);
var query = from p in db.VERSIONs where p.vr_key == key select p;
1 Comment
oscilatingcretin
Dang. Every time I bust out VS2010 to test a workable solution, someone else beats me to it.
Use TryParse method to make sure your string is compatible/ convertible because query string can be anything. Otherwise a user can easily break your code simply typing something for key.
double key;
if(Double.TryParse(Request.QueryString["key"], out key))
{
var query = from p in db.VERSIONs
where p.vr_key == key
select p;
}
3 Comments
Linus Caldwell
+1 for the even better solution. Parsing a
QueryString without checking is risky.oscilatingcretin
It's only risky if you don't know whether or not the string you're parsing is the type you're looking for.
Indi
@oscilatingcretin: user can type anything on address bar and enter. ex : www.yoursite.com?key=hello
Use SqlFunctions.StringConvert to convert p.vr_key.
Try this:
key = Request.QueryString["key"];
var query = from p in db.VERSIONs where SqlFunctions.StringConvert(p.vr_key) == key select p;
1 Comment
David L
I did not give you the downvote but I'm assuming it's because you converted the database value to a string rather than parsing the key value to a double to match the database type
p.vr_keyis of type double like your message says.