Visual Basic

Re: Creating PDF writer in .net

26-Mar-04 2:39

The first place to start would be http://developer.adobe.com. You'll need the specifications for the format of a .PDF file. Warning: Not free...

You can look at a couple of open source projects at http://sourceforge.net[^] like PDFCreator and iText.

RageInTheMachine9532

DHARMA.R26-Mar-04 4:03

DHARMA.R

26-Mar-04 4:03

Hi Dave,

Thank u v much for ur valuable help.
I will check it now.

Thanks
DHARMA.R

DHARMA.R

ant algorithm with visual basic??

pahlawan_siber25-Mar-04 20:12

pahlawan_siber

25-Mar-04 20:12

, i'm a new pwerson in this forum so please give me some lessons ok..;) Here i've got some problem that i want to learn the ant algorithm, not genetic algorithm using visual basic 6. As a student, i thought this ant algorithm is very interesting to me. So does anybody in this forum can teach me about the ant algorithm using visual basic?? How it's work?? Some example?? I hope that someone can teach me ok... Smile | :)

Thanks.

Re: ant algorithm with visual basic??

Dave Kreskowiak26-Mar-04 2:43

changing code to add subs and to call on subs

26-Mar-04 2:43

We can help you with coding problems. But forums like this are not the place the be teaching entire algorithms. You'll have much better (and faster!) results searching the web for "Ant algorithm". On Yahoo, I came up with LOTS of documents and code samples...

There's even an article here on CodeProject: http://www.codeproject.com/cpp/GeneticandAntAlgorithms.asp[^]

RageInTheMachine9532

ibok2325-Mar-04 15:01

25-Mar-04 15:01

I am having to change my code so that I will have some subs and so that I can call on the subs. Here is my code for under the btncalculate button. Could anybody give me suggestions on how to put in subs and to change my code where it will still work.

Private Sub btncalculate_Click(ByVal sender As System.Object, ByVal e As System.EventArgs) Handles btncalculate.Click
        Dim amount As Single
        'Finding out how much they will be payig just for the room - with no extras.
        If radstandard.Checked = True Then
            costofroom.Text = standardrate
            costofroom.Text = Format(standardrate, "currency")


        ElseIf raddeluxe.Checked = True Then
            costofroom.Text = deluxerate
            costofroom.Text = Format(deluxerate, "currency")
        ElseIf radsuite.Checked = True Then
            costofroom.Text = suiterate
            costofroom.Text = Format(suiterate, "currency")

        End If

        'Figuring out how many days that they want the room.
        numberofdays.Text = DateDiff(DateInterval.Day, dtparrival.Value, dtpcheckout.Value) + 1

        'Finding out the cost if they need an additional bed.
        Dim newcharge As Double = rollawaybed * Val(numberofdays.Text)

        If chkbed.Checked = True Then
            rollawaybedcharge.Text = Format(newcharge, "currency")
        Else : rollawaybedcharge.Text = 0
            rollawaybedcharge.Text = Format(0, "currency")
        End If

        'Finding out how many are going to be in the room.
        'Finding out how much it is going to cost for more than 2 people in the room.
        Dim additionalguest As Double = ((nudguest.Text - 2) * 10) * Val(numberofdays.Text)


        If nudguest.Text > 2 Then
            additionalguestcharge.Text = additionalguest
            additionalguestcharge.Text = Format(additionalguest, "currency")          '((((nudguest.Text - 2) * 10) * Val(numberofdays.Text)), "currency")
        Else
            additionalguestcharge.Text = 0
            additionalguestcharge.Text = Format(0, "Currency")
        End If

        'Calculating just how much the room is going to cost with the number of Days staying there.
        subtotal.Text = ((numberofdays.Text) * (costofroom.Text))
        subtotal.Text = Format(((numberofdays.Text) * (costofroom.Text)), "currency")

        'Calculating the total for the room with everything
        total = CInt(CInt(subtotal.Text) + CInt(additionalguestcharge.Text) + CInt(rollawaybedcharge.Text))

        txttotal.Text = Format(total, "C")

I am not sure what to do. I am confused on how to do this.

End Sub

Thank you,

ibok23

ibok2325-Mar-04 15:09

25-Mar-04 15:09

I was also told to move my subs around. Not sure what this means.

Thank you,

ibok23

Nadroj25-Mar-04 18:14

Nadroj

25-Mar-04 18:14

well i dunno how much help this is going to be... very tired, i cant read all that right now, lol.. but
do u simply need to create subs for the fact that some1 wants you to and you dont know how?

i can start you off with this one. put this one in its own sub 4 sure. to do it, just go and cut the text from the button click event code and make another sub and paste the code in there, as shown:

private sub SetCost()
'Finding out how much they will be payig just for the room - with no extras.        
If radstandard.Checked = True Then 
        costofroom.Text = standardrate
        costofroom.Text = Format(standardrate, "currency") 
ElseIf raddeluxe.Checked = True Then    
        costofroom.Text = deluxerate       
        costofroom.Text = Format(deluxerate, "currency")   
ElseIf radsuite.Checked = True Then         
        costofroom.Text = suiterate       
        costofroom.Text = Format(suiterate, "currency")   
End If
end sub

and to call this from the button click code, simply, in the button click event code type SetCost(). it will then go out and do the code in the SetCost method and return to the button click event where it left off.

since this section doesnt deal with any of the variables in the rest of the button click code, it can definetly b put in its own sub.

you should b able to separate the rest. just b logical about it, look thru it. ex., the ''Figuring out how many days that they want the room.' comment you have there can b cut and pasted into another new sub, called, say, RoomDays, whatever. just follow the same example as the SetCost sub. dont separate parts in2 its own sub if it has variables that are also required in the button click event.
... well, you can use functions for this rather than subs, but keep it simple for now and use subs. lol... forget that last sentence, it was more 4 other ppl reading this and yelling at me about it.

NOTE: i STRONGLY suggest (as all programmers will), since you seem somewhat new, start using camel casting for your variables. this means, when u declare a variable (anything..[to an extent].. when you NAME something), use lower case for all letters, except the 1st letter of every word after the 1st word...
ex:
costofroom should be camel casted to costOfRoom. MUCH easier for other people to read and help you debug code. prettier for the eyes. nearly a standard.

------------------------
Jordan.
III

ibok2326-Mar-04 2:55

26-Mar-04 2:55

Ok,

I have moved that over underneath the Private sub costofroom_textchanged section.

Now underneath the btncalculte I wrote costofroom() and I got errors.

Now what am I doing wrong?

Did I move it to the wrong section? I do not have

private sub setcost () I tried to put that under the private sub costofroom and it gave me an error.

if i need to copy it over and paste it here let me know.

Thank you,

ibok23

Dave Kreskowiak26-Mar-04 3:32

26-Mar-04 3:32

I've rewritten some of your code in your first post. It should provide a couple of examples for you to follow. You can rewrite three more sections of your original code into Functions. I'll leave it to you to figure out which sections and how to write the functions:

    Private Sub btncalculate_Click(ByVal sender As System.Object, ByVal e As System.EventArgs) Handles btncalculate.Click
        'Finding out how much they will be payig just for the room - with no extras.
        CalculateBaseCostOfRoom()
 
        'Figuring out how many days that they want the room.
        numberofdays.Text = CalculateDays(dtparrival.Value, dtpcheckout.Value)
 
        'Finding out the cost if they need an additional bed.
        Dim newcharge As Double = rollawaybed * Val(numberofdays.Text)
        If chkbed.Checked = True Then
            rollawaybedcharge.Text = Format(newcharge, "currency")
        Else
            rollawaybedcharge.Text = Format(0, "currency")
        End If
 
        'Finding out how much it is going to cost for more than 2 people in the room.
        additionalguestcharge.Text = Format(additionalguest, "currency")
 
        'Calculating just how much the room is going to cost with the number of Days staying there.
        subtotal.Text = Format(((numberofdays.Text) * (costofroom.Text)), "currency")
 
        'Calculating the total for the room with everything
        total = CInt(CInt(subtotal.Text) + CInt(additionalguestcharge.Text) + CInt(rollawaybedcharge.Text))
        txttotal.Text = Format(total, "C")
    End Sub


    ' I know this is the long way to write these, but it's easier to follow for beginners...
 
    'This Sub doesn't take any parameters and doesn't return any value to the caller.
    Private Sub CalculateBaseCostOfRoom()
        If radstandard.Checked = True Then
            costofroom.Text = Format(standardrate, "currency")
        ElseIf raddeluxe.Checked = True Then
            costofroom.Text = Format(deluxerate, "currency")
        ElseIf radsuite.Checked = True Then
            costofroom.Text = Format(suiterate, "currency")
        End If
    End Sub

    'This Function takes two DateTime objects as parameters.  These will come from the Value properties
    'of your DateTimePicker controls, dtpArrival and dtpCheckout.  This Function will return a Long type
    'value representing the number of nights these dates span.
    Private Function CalculateDays(ByVal startDate As DateTime, ByVal endDate As DateTime) As Long
	Dim numDays As Long
 
        numDays = DateDiff(DateInterval.Day, startDate, endDate) + 1
        Return numDays
    End Function

    'This Function doesn't take any parameters, but will return a Double type value representing the
    'additional cost of the room.
    Private Function CalculateAdditionalGuests() As Double
	Dim additionalguest As Double
 
        If Val(nudguest.Text) > 2 Then
            additionalguest = ((Val(nudguest.Text) - 2) * 10) * Val(numberofdays.Text)
        Else
            additionalguest = 0
        End If
 
        Return additionalguest
    End Function

RageInTheMachine9532

Dave Kreskowiak26-Mar-04 2:52

26-Mar-04 2:52

ibok23 wrote:

If radstandard.Checked = True Then
    costofroom.Text = standardrate
    costofroom.Text = Format(standardrate, "currency")
ElseIf raddeluxe.Checked = True Then
    costofroom.Text = deluxerate
    costofroom.Text = Format(deluxerate, "currency")
ElseIf radsuite.Checked = True Then
    costofroom.Text = suiterate
    costofroom.Text = Format(suiterate, "currency")
End If

The bolded sections of your code are unnecessary. You're assigning a value to a TextBox then immediately replacing that value with a different one. Your code is full of this pattern. Shorten it up by removing the first assignment, like this:

If radstandard.Checked = True Then
    costofroom.Text = Format(standardrate, "currency")
ElseIf raddeluxe.Checked = True Then
    costofroom.Text = Format(deluxerate, "currency")
ElseIf radsuite.Checked = True Then
    costofroom.Text = Format(suiterate, "currency")
End If

RageInTheMachine9532

ibok2326-Mar-04 2:57

26-Mar-04 2:57

Thanks,

I am suppose to be calling on subs and not have everything underneath the button calculate. I am trying the suggestion up top, but not sure where to copy and paste this section and how to call upon it.

Thank you,

ibok23

ibok2326-Mar-04 4:36

26-Mar-04 4:36

I think I figured it out. I created its own private sub then called for the sub. I wasn't suppose to put it under the btn for that box. My fault.
Thanks for the suggestions and examples - it helps.

Tammy Blush | :O

Thank you,

ibok23

Nadroj26-Mar-04 4:47

Nadroj

26-Mar-04 4:47

ya.. i think u were getting the errors from afew posts earlier from the sub that you made with the "_textchanged" at the end of it.. since you never made a sub called exactly "costofrooms", but rather "costofrooms_textchanged". the error occured b/c there was no sub existing that you were tryting to call (costofrooms()), right?
all working now?

------------------------
Jordan.
III

ibok2326-Mar-04 5:09

26-Mar-04 5:09

As far as I know. I am just in the process of commenting on the code itself.

Blush | :O

Thank you,

ibok23

Nadroj26-Mar-04 6:45

Nadroj

26-Mar-04 6:45

alrighty. hope i was of some assistance.

and remember... CAMEL CASTING.
------------------------
Jordan.
III

ibok2326-Mar-04 9:21

Exceptions or Return Values

26-Mar-04 9:21

don't worry you were. Thanks.

Tammy Big Grin | :-D

Thank you,

ibok23

Anonymous25-Mar-04 10:48

Anonymous

25-Mar-04 10:48

I'm creating an n-tier application that I want to implement decent error handling in. Its probably best to describe an Example and request comment.

The presentation layer is a form to Redeem a coupon. The user enters into the form details and has a submit button.

The business logic layer (Redeem function) will do some basic checking such as the coupon hasnt been validated already or cancelled or expired and if OK will perform the status chnage to indicate that it has now been redeemed.

The data access layer consists of simple getstatus and changestatus functions to call stored procedures.

In this example the data access or business logic layers could fail as a result of a whole host of items - such as SQL problems or invalid status for the action.

If I went with the approach I'm more familar with which is from a VB6 background - I could return different codes from the functions and track in the calling function and control the actions as a result of these different problems. I'd probably set up a enumeration in a interface file used by all components - so that I dont just use magic numbers but that the return code is either success or a code indicating cause of the problem. But I'd still need some exception handling to deal with all other eventuallities.

The more .NET approach may be to create custom exceptions for the application. And throw these errors instead of return codes. This would allow the exceptions to bubble to a layer where they are dealt with. The functions would then return either a success or throw an exception.

Only small simple functions that only require a success or failure would possibly use return code values other than success.

This would require some custom exceptions created for situations like ItemDoesntExist and InvalidStateTransition but I could see this being a nice approach as all functions would have exception handlers and a pretty standard template would be used by deafult on all functions with addition of catch statements for more specifics to be dealt with.

In above example I'd have a different form that would be called if something didn't exist to if the action was invalid because say the status' were incorrect. This is why I'd need specific reasons as to why something had failed.

Any thoughts on these two approaches ? I could use either.....

Re: Exceptions or Return Values

Pradeep C27-Mar-04 5:44

Pradeep C

27-Mar-04 5:44

I think that it would be better to use Exceptions as the .NET framework itself uses it.

"I think there is a world market for maybe 5 computers"
Thomas Watson, chairman of IBM, 1943

"There is no reason anyone would want a computer in their home"
Ken Olson, chairman & founder of Digital equipment, 1977

"This 'telephone' has too many shortcomings to be seriously considered as a means of communication. The device is ingerently of no value to us."
Western Union internal memo, 1876

"640 K ought to be enough for anybody."
Bill Gates, 1981

"Computers in the future may

How do I delete data??

Pugzley25-Mar-04 2:14

Pugzley

25-Mar-04 2:14

I add data using the following method:

Open "text.txt" For Append As #1
Write #1, Display.Text, ID.Text
Close #1
'next section adds data in text.txt to a list box
Open "text.txt" For Input As #1
x = 1
Do While Not EOF(1)
Input #1, username, user_id
List1.AddItem username
x = x + 1
Loop
Close #1

How do i delete the data which i select from the list box??

Re: How do I delete data??

Dave Kreskowiak25-Mar-04 4:15