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Variable declaration!!!

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gouki2005

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Variable declaration!!!

Aug 13th, 2008

I have a class named Account so I have a question. In the declarations of a new instance

Dim Newaccount as Account -----but I can declare this like..
Dim Newaccount As Account = New Account

which are the differences between both declarations?? are the same or not?

excuse me english...

besides I have another question

I have 3 functions in mi clasee

writename()
writeaccount()
writesave()

the first 2 functinos are string..so i have this.

IF name = "" then
Console.writeline("name is empty")

is the same with account and save
but the problem with save is DOUBLE so if is ="" ..I have this error.....saying....Conversion string "" in TYPE DOUBLE is invalid.............

what I can do??? because I want textmessage saying "save is empty" IF is empty

Last edited by gouki2005; Aug 13th, 2008 at 4:37 am.

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waynespangler waynespangler is offline

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Re: Variable declaration!!!

Aug 13th, 2008

The first just declares a variable as the class. The second creates an instance of it.
Without seeing your code I would say you need to put in "Exit Sub" after your If statement.
If it is a subroutine:

 Help with Code Tags 
 VB.NET Syntax (Toggle Plain Text) 
IF name = "" then Console.writeline("name is empty") : Exit Sub
IF name = "" then Console.writeline("name is empty") : Exit Sub

If it is a function:

 Help with Code Tags 
 VB.NET Syntax (Toggle Plain Text) 
IF name = "" then Console.writeline("name is empty") : Return Nothing
IF name = "" then Console.writeline("name is empty") : Return Nothing

Last edited by waynespangler; Aug 13th, 2008 at 5:50 am.

Wayne

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gouki2005

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Re: Variable declaration!!!

Aug 13th, 2008

Sorry..the 3 are not function the 3 are SUb.....so how can I fix the error with double type..string is not a problem....but when is double...a exception..appears..

beside the diffrences between

use a instance of the class with using a variable.to use the class...like my first post

Last edited by gouki2005; Aug 13th, 2008 at 1:42 pm.

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selvaganapathy selvaganapathy is offline

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Re: Variable declaration!!!

Aug 13th, 2008

hi,

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Dim Newaccount as Account -----but I can declare this like..
Dim Newaccount As Account = New Account

First one is just a Reference not Referring any object. With out referring any object using reference (Like first one) is an exception (NullPointerException)

Second one is a reference and referring an Account object.

And then

Are you mean how to check when double valued field is left out? I think so

when no value given to double (that is default value ) is 0.0

So

 Help with Code Tags 
 VB.NET Syntax (Toggle Plain Text) 
Dim Save As Double
.....
  If Save = 0.0 Then
        MessageBox.Show ("Empty Double")
  End If
Dim Save As Double
.....
  If Save = 0.0 Then
        MessageBox.Show ("Empty Double")
  End If

KSG

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gouki2005

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Re: Variable declaration!!!

Aug 13th, 2008

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Originally Posted by selvaganapathy

hi,

First one is just a Reference not Referring any object. With out referring any object using reference (Like first one) is an exception (NullPointerException)

Second one is a reference and referring an Account object.

And then

Are you mean how to check when double valued field is left out? I think so

when no value given to double (that is default value ) is 0.0

So
Help with Code Tags

VB.NET Syntax (Toggle Plain Text)
Dim Save As Double
.....
  If Save = 0.0 Then
        MessageBox.Show ("Empty Double")
  End If
Dim Save As Double ..... If Save = 0.0 Then MessageBox.Show ("Empty Double") End If

yeah but I am creating the error message in the sub..beside..is not working.neither...if the user doesnt write nothing and the field is empty like this = "" a exception appears I try the 0.0 but nothing the same.. string "" cant convert to double

Public Sub save(ByVal sav As Double)
If sav= 0.0 Then
Console.WriteLine("Is not valid")

Else

mainsave = sav
End If

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uma123

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VB.NET Project

Aug 14th, 2008

i need sample project using vb.net if u know anything please send me

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uma123

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Re: Variable declaration!!!

Aug 14th, 2008

i need vb.net sample projects

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manal

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Re: Variable declaration!!!

Aug 14th, 2008

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Help with Code Tags

VB.NET Syntax (Toggle Plain Text)
Public Sub save(ByVal sav As Double)
If sav= 0.0 Then
Console.WriteLine("Is not valid")
 
Else
 
mainsave = sav
End If
Public Sub save(ByVal sav As Double) If sav= 0.0 Then Console.WriteLine("Is not valid") Else mainsave = sav End If

what I understand that the user will enter the value in textbox , after you check that user did not leave it empty you can use it .

 Help with Code Tags 
 VB.NET Syntax (Toggle Plain Text) 
 
        Dim save As Double
        If TextBox1.Text = "" Then  ' check if the textbox is empty
            save = 0.0
            MessageBox.Show("Empty Double")
        Else
            save = Convert.ToDouble(TextBox1.Text) 'if it is not empty convert the string to double and store it in save variable 
 
        End If
        Dim save As Double
        If TextBox1.Text = "" Then  ' check if the textbox is empty
            save = 0.0
            MessageBox.Show("Empty Double")
        Else
            save = Convert.ToDouble(TextBox1.Text) 'if it is not empty convert the string to double and store it in save variable 
            
        End If

also you can validate the user's input before you store it in save variable.
I hope that help you

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i need sample project using vb.net if u know anything please send me

it is better you open new thread, and i suggest to search here since many ask same thing , Good Luck

Last edited by manal; Aug 14th, 2008 at 11:24 am.

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