Datatype validation

[manishsawant]

Hi,

I want to check if a string is a int or a number with 2 decimals or 4 decimals. I tried this
if (double.TryParse(dr[Col].ToString(),NumberStyles.Currency,CultureInfo.CurrentCulture, out result))

but it doesnt work for 4 decimals like "11.1245".

Similarly i want to check a string which might contain something like 20070518 which is a valid date for us. I want to check if this is a date in a if statement.

I am using C# 2.0.

Can anyone please help me with this.

Thanks,
Manish

 

[AlexCuse]

If you want to check a string for a valid date, I would jsut do this (you really don't want to do it on your own I don't think).

try {
DateTime myDT = Convert.ToDateTime(myString);
}
catch (exception ex)//I forget the exact exception type, DateFormat?
{
MessageBox.Show("Invalid Date Entered")
}

To check how many decimal places you have, perhaps you could simply reverse teh string and take indexOf the '.' ?

-1, 3, and 5 will be acceptable values, all others will not if I understand you correctly.

Hope this helps,

Alex



Ignorance of certain subjects is a great part of wisdom

 

[JurkMonkey]

This is the time when you will want to look into Regular Expressions (Regex)

The Match() method is what you are looking for...

 

[manishsawant]

Hi Guys,

Thanks for the responses. Even i feel regex is a good option. But is there any expression to check if it is a date. The database will always return me a string like "20070718". So i want to differentiate date and numbers.

Thanks,
Manish

 

[chrissie1]

The database will always return me a string like "20070718".

Then you have a design problem.

Christiaan Baes
Belgium

"My old site" - Me

 

[jmeckley]

if the db returns yyyyMMdd then you will need something like this

public static DateTime? ConvertDate(string dateAsString)
{
   [COLOR=green]//validate string is not null[/color]
   if(string.IsNullOrEmpty(dateAsString))
   {
      return null;
   }

   [COLOR=green]//validate string is 8 characters[/color]
   if(dateAsString.length != 8)
   {
      return null;
   }

   [COLOR=green]//validate year[/color]
   int year = 0;
   if (!int.TryParse(dateAsString.SubString(0, 4), out year))
   {
      return null;
   }

   [COLOR=green]//validate month[/color]
   int month = 0;
   if (!int.TryParse(dateAsString.SubString(4, 2), out month))
   {
      return null;
   }

   [COLOR=green]//validate day[/color]
   int day = 0;
   if (!int.TryParse(dateAsString.SubString(6, 2), out day))
   {
      return null;
   }

   [COLOR=green]//validate date[/color]
   try
   {
      return new DateTime(year, month, day);
   }
   catch (FormatException)
   {
      return null;
   }
}

this is obviouly tedious. so this may work as well

DateTime date = DateTime.MinValue;
bool valid = DateTime.TryParse(DateAsString, out date);

Jason Meckley
Programmer
Specialty Bakers, Inc.

 

[JurkMonkey]

Then you have a design problem.

I second that statement.

 

[manishsawant]

Hi,

Thanks for all the responses. The client just said that they have a different system which will return that kind of a format from a web service which they will be exposing. So i want to be rest assured that i will be ready for parsing the format.

I did try DateTime.TryParse but it didnt work.

Thanks,
Manish

 

[chrissie1]

Why don't they expose a date type?

Christiaan Baes
Belgium

"My old site" - Me

 

[stevexff]

Why don't they expose a date type?

If I had a quid for every time I've found dates stored as strings on a database, I would have retired by now...

Steve

[small]"Every program can be reduced by one instruction, and every program has at least one bug. Therefore, any program can be reduced to one instruction which doesn't work." (Object:erlDesignPatterns)[/small]

 

[AlexCuse]

Hey, that makes it easier to get your data into the database ;-)

I think that your web service may be provided by an Uncle Rico (See Definition #3)

Ignorance of certain subjects is a great part of wisdom

 

[chrissie1]

I would have retired by now...

Is that good or bad?

Christiaan Baes
Belgium

"My old site" - Me

 

[manishsawant]

Guys,

The date is stored as datetime in the database. The client wants to display date in yyyymmdd format so they are sending it that way. The webservice sends me a string which contains xml. Can you recognize "20070511" is a date from a xml? Now the question is why i want to recognize it as a date if i just want to display it in the grid. I want to display all numbers as right aligned and everything else as left aligned. I hope that made sence.

Jason,

Thanks your method did work.

Regards,
Manish

 

[JurkMonkey]

If you're pulling it from XML then you should know what you're expecting. The tag should be something like "StartDate" in which you know you're looking for a date.

That is afterall the point of a tag in xml - to identify the data being stored.

 

[chrissie1]

Or they could send it as date. Since when do you do formatting on the "data"-side?

Only uncle rico saves his dates as string.

Formatting is done on the view side all the rest is "rubbish".

Christiaan Baes
Belgium

"My old site" - Me

 

[AlexCuse]

>>>Formatting is done on the view side all the rest is "rubbish".

Said much more politely than I would have, Christiaan! ;-)




Ignorance of certain subjects is a great part of wisdom