Setting an ID as an Integer with C#

Question

I am currently using the following script to set this value as a String:

string ID = Request.QueryString["ID"].ToString();

However, I'd now like to store it as an Integer.

How do I do this?

Many thanks for any pointers.

Bob Vale · Accepted Answer · 2012-03-22T10:24:23.013

5

Assuming you don't want to throw a server error on a bad string

int id=0;
if (int.TryParse(Request.QueryString["ID"],out id)) {
  .. logic for valid id
} else {
  .. logic for invalid id
}

edited Mar 22 '12 at 10:24

answered Mar 22 '12 at 10:16

Bob Vale

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You don't need the `ToString()`, the `QueryString` property already returns indexed values as strings. – Quick Joe Smith Mar 22 '12 at 10:22
1

@QuickJoeSmith Doh, was on automatic I meant to remove that. Now updated – Bob Vale Mar 22 '12 at 10:25
For all I know, redundant call is probably optimised away anyway. – Quick Joe Smith Mar 22 '12 at 10:26
You don't really need the .QueryString part either, you can just do Request["ID"], although using the Request.QueryString is a bit more readable – JCherryhomes Mar 22 '12 at 12:26
Bear in mind that `Request[key]` will search server variables, cookies and form fields as well as the query string. There are plenty of situations in which where a value comes from is just as important as what its value is. – Quick Joe Smith Mar 22 '12 at 21:18

score 3 · Answer 2 · edited Mar 22 '12 at 10:17

3

int ID = int.Parse(Request.QueryString["ID"].ToString());

edited Mar 22 '12 at 10:17

gdoron

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answered Mar 22 '12 at 10:14

daryal

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score 2 · Answer 3 · answered Mar 22 '12 at 10:16

Use either of these:

If you know that you have an ID:

string ID = Request.QueryString["ID"];
int integerId = int.Parse(ID);

or, if the query string may be missing or invalid (never trust query strings....)

string ID = Request.QueryString["ID"];
int integerId;
if (int.TryParse(ID, out integerId))
{
   // you have a valid integer ID here.
   // process it
}
else
{
    // handle missing or invalid ID
}

score 1 · Answer 4 · answered Mar 22 '12 at 10:15

1

You could do something like:

int i = Convert.ToInt32(ID);

or

int i;
Int32.TryParse(ID, out i);

BTW Request.QueryString["ID"] is already a string so the following is fine:

string ID = Request.QueryString["ID"];

answered Mar 22 '12 at 10:15

Barry Kaye

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score 0 · Answer 5 · edited May 23 '17 at 12:11

0

Try

int ID = int.Parse(Request.QueryString["ID"]);

See How can I convert String to Int?

edited May 23 '17 at 12:11

Community

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answered Mar 22 '12 at 10:15

Pavel Chuchuva

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score 0 · Answer 6 · edited Mar 22 '12 at 10:18

0

You can do like this:

string ID = Request.QueryString["ID"].ToString();

int id=int.Parse(ID);

or

int id=Convert.ToInt16(ID);

edited Mar 22 '12 at 10:18

gdoron

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answered Mar 22 '12 at 10:17

ankit rajput

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score 0 · Answer 7 · answered Mar 22 '12 at 10:30

Always use tryparse for querystring values if you want to convert it to integer even if you never set it to string , because user can change that anytime before sending request (visible in URL).

int id = 0 ;//default value

bool success = int.TryParse(Request.QueryString["ID"],out id))

if (success) { //write code for default value action return; }

//write code for other values.

Setting an ID as an Integer with C#

7 Answers7