ASP.NET

2-May-06 5:09

I am trying to determine if a file is a jpeg

I know I should use the System.Drawing.Imaging.Image class.

And I can see the enumeration to show me what type.

But I can't find a property or method to extract that information.

Please, no answers telling me to check the extension in the file name.

Thanks for helping me.

Thanks,
Nick

1 line of code equals many bugs. So don't write any!!

Paddy Boyd2-May-06 6:24

Paddy Boyd

2-May-06 6:24

Assuming that this is an uploaded file from the client - can you check the mime type?

Ista2-May-06 9:56

2-May-06 9:56

nah. I want to check the file internally. I only want jpeg avatars so I need to make sure the file is a jpeg. I caught one user changing the extension name to fool me.

Thanks tho.

1 line of code equals many bugs. So don't write any!!

Guffa2-May-06 7:19

Guffa

2-May-06 7:19

You can read the first few bytes of the file and see if it contains a valid JPEG header.

---
b { font-weight: normal; }

Ista2-May-06 9:57

2-May-06 9:57

Yeah, I could. But I want the framework to tell me what it is.

I think hacking into the file, while valid, isn't the solution I was looking for.

Thanks for helping tho.

Nick

1 line of code equals many bugs. So don't write any!!

-- modified at 15:57 Tuesday 2nd May, 2006

Josh Smith2-May-06 9:13

Josh Smith

2-May-06 9:13

If the file can be loaded into a Bitmap object, then you can use this test to see if it is a JPEG/JPG type image:

if( someBitmap.RawFormat.Guid == System.Drawing.Imaging.ImageFormat.Jpeg.Guid ) {}

Josh

Ista2-May-06 9:54

2-May-06 9:54

Alright cool. I recognize that form from the Image class.

thanks. thats perfect.

1 line of code equals many bugs. So don't write any!!

Datepicker problem

macca242-May-06 4:49

macca24

2-May-06 4:49

I have a popup datepicker in my application which is ran using javascript. When I run my application from my pc it works fine but wehen I run my app from a server it causes a problem. The problem is that if I select a date like today 02/05/2006 this will go into the field on my app, when I submit the form in the date goes into the datbase field as 05/02/2006 which is the wrong way round. I am using GMT as the time zone regional setting. The field in the database is datetime.
Anyone any ideas why this is happening?

macca

Siva Subramanian2-May-06 5:09

Siva Subramanian

2-May-06 5:09

Simple. Its getting converted to the american format of storing dates. The solution is very simple. Just before writing to the Database, make sure that you pass it as a DateTime variable using some syntax like,

DateTime dt=DateTime.Parse(dtPicker.SelectedDate.ToString("dd-MM-yyyy");

Hence even if a value such as 02/05/2006 is stored in the database as 05/02/2006, while retrieving it will still get you 02/05/2006 once you get it with the same format as dt.ToString("dd-MM-yyyy");

macca242-May-06 5:31

macca24

2-May-06 5:31

It is being passed into the stored procedure in the British format, so I think I need to do the conversion you are proposing in the datbase itself. Can I use your code "DateTime dt=DateTime.Parse(dtPicker.SelectedDate.ToString("dd-MM-yyyy");" in the stored procedure?

I need it stored in the dataase in the correct format as I run some other queries based on the dates i.e. select all between two dates.

macca

J4amieC2-May-06 5:53

J4amieC

2-May-06 5:53

The answer is that using dd/mm/yyyy and/or mm/dd/yyyy is ambiguous - it looks like your webserver is configured to use UK date format, but that your sql server instance has been installed to use US format.

I have always gotten around this by using an unambiguaous format. So either:

1) 2 May 2006
2) 2006/05/02

Both are unambiguous and will never cause the problems you specify.

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