Casting to double in C#

[kanepart2]

Hi guys, I am having a problem with the following code snippet:-

double x = (myReader["TimeStamp"]);
double y = (myReader["YAxis"]);

Resulting in the follwing compilation error:

Cannot implicitly convert type 'object' to 'double'. An explicit
conversion exists (are you missing a cast?)
To fix this I modified the code to :-

double x = (double)(myRead er["TimeStamp"]);
double y = (double)(myRead er["YAxis"]);

with this there are no compilation errors but I get a runtime
exception saying :-

System.InvalidC astException: specified cast is not valid.

Any clues on how to fix this will be much appreciated.

[Jon Skeet [C# MVP]]

On Jun 8, 3:52 pm, kanepa...@hotma il.com wrote:

Hi guys, I am having a problem with the following code snippet:-

double x = (myReader["TimeStamp"]);
double y = (myReader["YAxis"]);

Resulting in the follwing compilation error:

Cannot implicitly convert type 'object' to 'double'. An explicit
conversion exists (are you missing a cast?)

To fix this I modified the code to :-

double x = (double)(myRead er["TimeStamp"]);
double y = (double)(myRead er["YAxis"]);

with this there are no compilation errors but I get a runtime
exception saying :-

System.InvalidC astException: specified cast is not valid.

Any clues on how to fix this will be much appreciated.

Yes - the cast is trying to unbox. It's probably in a different
format, eg decimal.

Print out myReader["TimeStamp"].GetType() and put an appropriate cast
in before the double, eg:
double x = (double)(deciml a)(myReader["TimeStamp"]);

Jon

[kanepart2]

Well , I tried what you said and it turns out that the type is string
and it doesnt allow conversions from string to double.
On Jun 8, 10:56 am, "Jon Skeet [C# MVP]" <[e-mail] wrote:

On Jun 8, 3:52 pm, kanepa...@hotma il.com wrote:

Hi guys, I am having a problem with the following code snippet:-

double x = (myReader["TimeStamp"]);
double y = (myReader["YAxis"]);

Resulting in the follwing compilation error:

Cannot implicitly convert type 'object' to 'double'. An explicit
conversion exists (are you missing a cast?)

To fix this I modified the code to :-

double x = (double)(myRead er["TimeStamp"]);
double y = (double)(myRead er["YAxis"]);

with this there are no compilation errors but I get a runtime
exception saying :-

System.InvalidC astException: specified cast is not valid.

Any clues on how to fix this will be much appreciated.

Yes - the cast is trying to unbox. It's probably in a different
format, eg decimal.

Print out myReader["TimeStamp"].GetType() and put an appropriate cast
in before the double, eg:
double x = (double)(deciml a)(myReader["TimeStamp"]);

Jon- Hide quoted text -

- Show quoted text -

[Johnny Jörgensen]

What happens if you try

double x = Convert.ToDoubl e(myReader["TimeStamp"]);

???

Cheers,
Johnny J.


<ka*******@hotm ail.comwrote in message
news:11******** *************@k 79g2000hse.goog legroups.com...

Hi guys, I am having a problem with the following code snippet:-

double x = (myReader["TimeStamp"]);
double y = (myReader["YAxis"]);

Resulting in the follwing compilation error:

Cannot implicitly convert type 'object' to 'double'. An explicit
conversion exists (are you missing a cast?)
To fix this I modified the code to :-

double x = (double)(myRead er["TimeStamp"]);
double y = (double)(myRead er["YAxis"]);

with this there are no compilation errors but I get a runtime
exception saying :-

System.InvalidC astException: specified cast is not valid.

Any clues on how to fix this will be much appreciated.

[kanepart2]

yea that worked. thanks for the help guys

On Jun 8, 11:18 am, "Johnny Jörgensen" <[e-mail] wrote:

What happens if you try

double x = Convert.ToDoubl e(myReader["TimeStamp"]);

???

Cheers,
Johnny J.

<kanepa...@hotm ail.comwrote in message

news:11******** *************@k 79g2000hse.goog legroups.com...

Hi guys, I am having a problem with the following code snippet:-

double x = (myReader["TimeStamp"]);
double y = (myReader["YAxis"]);

Resulting in the follwing compilation error:

Cannot implicitly convert type 'object' to 'double'. An explicit
conversion exists (are you missing a cast?)

To fix this I modified the code to :-

double x = (double)(myRead er["TimeStamp"]);
double y = (double)(myRead er["YAxis"]);

with this there are no compilation errors but I get a runtime
exception saying :-

System.InvalidC astException: specified cast is not valid.

Any clues on how to fix this will be much appreciated.- Hide quoted text -

- Show quoted text -

[cjard]

Double.TryParse can be more useful...

[Aneesh Pulukkul[MCSD.Net]]

On Jun 8, 8:18 pm, "Johnny Jörgensen" <[e-mail] wrote:

What happens if you try

double x = Convert.ToDoubl e(myReader["TimeStamp"]);

???

Cheers,
Johnny J.

<kanepa...@hotm ail.comwrote in message

news:11******** *************@k 79g2000hse.goog legroups.com...

Hi guys, I am having a problem with the following code snippet:-

double x = (myReader["TimeStamp"]);
double y = (myReader["YAxis"]);

Resulting in the follwing compilation error:

Cannot implicitly convert type 'object' to 'double'. An explicit
conversion exists (are you missing a cast?)

To fix this I modified the code to :-

double x = (double)(myRead er["TimeStamp"]);
double y = (double)(myRead er["YAxis"]);

with this there are no compilation errors but I get a runtime
exception saying :-

System.InvalidC astException: specified cast is not valid.

Any clues on how to fix this will be much appreciated.- Hide quoted text -

- Show quoted text -

try
{
double x = Double.Parse(my Reader["TimeStamp"]);
}
catch(....)/Handle exception here. If the string contains data that
cannot be parsed to double it would throw exception.)
{
...........
...........
}

[Johnny Jörgensen]

Great.

MS is recommending using direct casting (double) instead of Convert, but
often Convert will do the job where the direct casting fails (for some
reason I don't know)

Cheers,
Johnny J.


<ka*******@hotm ail.comwrote in message
news:11******** **************@ p77g2000hsh.goo glegroups.com.. .
yea that worked. thanks for the help guys

On Jun 8, 11:18 am, "Johnny Jörgensen" <[e-mail] wrote:

What happens if you try

double x = Convert.ToDoubl e(myReader["TimeStamp"]);

???

Cheers,
Johnny J.

<kanepa...@hotm ail.comwrote in message

news:11******** *************@k 79g2000hse.goog legroups.com...

Hi guys, I am having a problem with the following code snippet:-

double x = (myReader["TimeStamp"]);
double y = (myReader["YAxis"]);

Resulting in the follwing compilation error:

Cannot implicitly convert type 'object' to 'double'. An explicit
conversion exists (are you missing a cast?)

To fix this I modified the code to :-

double x = (double)(myRead er["TimeStamp"]);
double y = (double)(myRead er["YAxis"]);

with this there are no compilation errors but I get a runtime
exception saying :-

System.InvalidC astException: specified cast is not valid.

Any clues on how to fix this will be much appreciated.- Hide quoted
text -

- Show quoted text -

[Aneesh Pulukkul[MCSD.Net]]

On Jun 8, 8:30 pm, "Aneesh Pulukkul[MCSD.Net]" <anees...@gmail .com>
wrote:

On Jun 8, 8:18 pm, "Johnny Jörgensen" <[e-mail] wrote:

What happens if you try

double x = Convert.ToDoubl e(myReader["TimeStamp"]);

???

Cheers,
Johnny J.

<kanepa...@hotm ail.comwrote in message

news:11******** *************@k 79g2000hse.goog legroups.com...

Hi guys, I am having a problem with the following code snippet:-

double x = (myReader["TimeStamp"]);
double y = (myReader["YAxis"]);

Resulting in the follwing compilation error:

Cannot implicitly convert type 'object' to 'double'. An explicit
conversion exists (are you missing a cast?)

To fix this I modified the code to :-

double x = (double)(myRead er["TimeStamp"]);
double y = (double)(myRead er["YAxis"]);

with this there are no compilation errors but I get a runtime
exception saying :-

System.InvalidC astException: specified cast is not valid.

Any clues on how to fix this will be much appreciated.- Hide quoted text -

- Show quoted text -

try
{
double x = Double.Parse(my Reader["TimeStamp"]);}

catch(....)/Handle exception here. If the string contains data that
cannot be parsed to double it would throw exception.)
{
..........
..........

}- Hide quoted text -

- Show quoted text -- Hide quoted text -

- Show quoted text -

It seems Double.Parse accepts string parameters only.
Since this is an object, Convert.ToDoubl e is the apt one.

[Aneesh Pulukkul[MCSD.Net]]

On Jun 8, 8:30 pm, "Aneesh Pulukkul[MCSD.Net]" <anees...@gmail .com>
wrote:

On Jun 8, 8:18 pm, "Johnny Jörgensen" <[e-mail] wrote:

What happens if you try

double x = Convert.ToDoubl e(myReader["TimeStamp"]);

???

Cheers,
Johnny J.

<kanepa...@hotm ail.comwrote in message

news:11******** *************@k 79g2000hse.goog legroups.com...

Hi guys, I am having a problem with the following code snippet:-

double x = (myReader["TimeStamp"]);
double y = (myReader["YAxis"]);

Resulting in the follwing compilation error:

Cannot implicitly convert type 'object' to 'double'. An explicit
conversion exists (are you missing a cast?)

To fix this I modified the code to :-

double x = (double)(myRead er["TimeStamp"]);
double y = (double)(myRead er["YAxis"]);

with this there are no compilation errors but I get a runtime
exception saying :-

System.InvalidC astException: specified cast is not valid.

Any clues on how to fix this will be much appreciated.- Hide quoted text -

- Show quoted text -

try
{
double x = Double.Parse(my Reader["TimeStamp"]);}

catch(....)/Handle exception here. If the string contains data that
cannot be parsed to double it would throw exception.)
{
..........
..........

}- Hide quoted text -

- Show quoted text -- Hide quoted text -

- Show quoted text -

Or you can convert the value to string and then parse - better avoid
two conversions.