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How to check data type

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How to check data type

Aug 7th, 2006

Guys anyone knows how to check if a value entered in a text box
i.e. text3.text=integer value is integer or long

i found a function that checks wether the text is numeric or not "isNumeric" but i did not find any other function that checks if the value entered is integer?

any help??!!

best regards ,

lover99509

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Re: How to check data type

Aug 7th, 2006

There is no function to do what you want. All you have is a string of characters. When you convert into a number, you'll know. Short of counting the characters and analyzing whether the characters are greater than "32767" or "65535", just convert into a long and don't worry about it.

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Re: How to check data type

Aug 7th, 2006

If Val(Text1.text) > 0 or Text1.text = "0" then

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Re: How to check data type

Aug 7th, 2006

Hi
Try With This Code

 Help with Code Tags 
 Visual Basic 4 / 5 / 6 Syntax (Toggle Plain Text) 
If Val(Text1.text) > 0 or Text1.text = "0" then
  Print "Is Integer
Else
 Print "Not Integer"
End if
 
If Val(Text1.text) > 0 or Text1.text = "0" then
  Print "Is Integer
Else
 Print "Not Integer"
End if

Last edited by Comatose; Aug 7th, 2006 at 11:49 am. Reason: UnNeeded Bold Tags...?

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Re: How to check data type

Aug 7th, 2006

I suggest stopping them from introducing anything other than numbers, right off the bat (in the text1 keypress event):

 Help with Code Tags 
 Visual Basic 4 / 5 / 6 Syntax (Toggle Plain Text) 
Private Sub Text1_KeyPress(KeyAscii As Integer)
'
' Invalidate keystroke if not a digit, decimal point or backspace.
'
If (Not IsNumeric(Chr$(KeyAscii)) And (Chr$(KeyAscii) <> "." And Chr$(KeyAscii) <> vbBack)) Then KeyAscii = 0
 
End Sub
Private Sub Text1_KeyPress(KeyAscii As Integer)
'
' Invalidate keystroke if not a digit, decimal point or backspace.
'
If (Not IsNumeric(Chr$(KeyAscii)) And (Chr$(KeyAscii) <> "." And Chr$(KeyAscii) <> vbBack)) Then KeyAscii = 0

End Sub

And then test between the int or long variable types using vartype as so:

 Help with Code Tags 
 Visual Basic 4 / 5 / 6 Syntax (Toggle Plain Text) 
if vartype(retval) = vbinteger then
     msgbox "is integer"
end if
if vartype(retval) = vbinteger then
     msgbox "is integer"
end if

Here is a table of such data:

 Help with Code Tags 
 Visual Basic 4 / 5 / 6 Syntax (Toggle Plain Text) 
 	vbEmpty   	Empty and not initialized argument
vbNull 	        Invalid data or a null string argument
vbInteger 	Integer argument
vbLong 	        Long argument
vbSingle 	Single argument
vbDouble 	Double argument
vbCurrency 	Currency argument
vbDate 	        Date argument
vbString 	String argument
vbObject 	Object argument
vbError 	Error argument
vbBoolean 	Boolean argument
vbVariant 	Variant argument
vbDataObject 	Data Access Object (DAO) argument; an advanced database value such as a field or record
vbDecimal 	Decimal argument
vbByte 	        Byte argument
8192+int 	vbArray 	Array argument of the type specified by the int addition to 81920   	 vbEmpty   	Empty and not initialized
 	vbEmpty   	Empty and not initialized argument
vbNull 	        Invalid data or a null string argument
vbInteger 	Integer argument
vbLong 	        Long argument
vbSingle 	Single argument
vbDouble 	Double argument
vbCurrency 	Currency argument
vbDate 	        Date argument
vbString 	String argument
vbObject 	Object argument
vbError 	Error argument
vbBoolean 	Boolean argument
vbVariant 	Variant argument
vbDataObject 	Data Access Object (DAO) argument; an advanced database value such as a field or record
vbDecimal 	Decimal argument
vbByte 	        Byte argument
8192+int 	vbArray 	Array argument of the type specified by the int addition to 81920   	 vbEmpty   	Empty and not initialized

Now, as was stated above, a textbox will only return a string. There is no other means by which a textbox will contain data. A number, too, can be a string, "1" is a string, but it's a character that represents a digit. If you need a number in a specific variable type, though, you can "cast" it to the desired type. So, if you need the information in the textbox to be a long, you can simply assign a variable to it's cast type:

 Help with Code Tags 
 Visual Basic 4 / 5 / 6 Syntax (Toggle Plain Text) 
dim TypedData as long
TypedData = CLng(Text1.Text)
dim TypedData as long
TypedData = CLng(Text1.Text)

You could also do the same with integer values, as in CInt(text1.text)

Last edited by Comatose; Aug 7th, 2006 at 2:43 pm.

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Re: How to check data type

Aug 8th, 2006

I think we're getting away from the original question, which was

•

Originally Posted by lover99509

Guys anyone knows how to check if a value entered in a text box
i.e. text3.text=integer value is integer or long

Doesn't this mean:

I have a number in a text box. How can I tell if I need an Integer or a Long when it's converted from ASCII to binary?

Or am I interpreting this wrong?

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Re: How to check data type

Aug 8th, 2006

this solution will work

 Help with Code Tags 
 Visual Basic 4 / 5 / 6 Syntax (Toggle Plain Text) 
Private Sub Text1_KeyPress(KeyAscii As Integer)
'
' Invalidate keystroke if not a digit, decimal point or backspace.
'
If (Not IsNumeric(Chr$(KeyAscii)) And (Chr$(KeyAscii) <> "." And Chr$(KeyAscii) <> vbBack)) Then KeyAscii = 0
 
End Sub
Private Sub Text1_KeyPress(KeyAscii As Integer)
'
' Invalidate keystroke if not a digit, decimal point or backspace.
'
If (Not IsNumeric(Chr$(KeyAscii)) And (Chr$(KeyAscii) <> "." And Chr$(KeyAscii) <> vbBack)) Then KeyAscii = 0

End Sub

but if i do like this:-

 Help with Code Tags 
 Visual Basic 4 / 5 / 6 Syntax (Toggle Plain Text) 
dim TypedData as long
TypedData = CLng(Text1.Text)
dim TypedData as long
TypedData = CLng(Text1.Text)

Data accurecy will be lost because if the user entered by mistake 9.8
then when the above instruction is excuted TypedData =10 (!!! rounding)

i have another solution which is using the method inStr which will test if the entered value contains the charecter "."

check if user entered only numeric values and test if it does not contain "."

lover99509
[/LEFT]

Last edited by Comatose; Aug 8th, 2006 at 6:16 am.

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Re: How to check data type

Aug 8th, 2006

•

Originally Posted by WaltP

I think we're getting away from the original question, which was
Doesn't this mean:
I have a number in a text box. How can I tell if I need an Integer or a Long when it's converted from ASCII to binary?

Or am I interpreting this wrong?

I would guess that he wants to ensure that numbers are all that is in the textbox, especially if he wants to see if the data entered is a long or integer.... so It looks to me as though the information is entirely relevant.

Lover99509: Right, because long is a integer type. You could cast it to a single, instead of clng, you could use csng, or cdbl. Which would cast it to a single or a double, which are both floating points. That would maintain your decimal point, and solve you from having to do string parsing.

Last edited by Comatose; Aug 8th, 2006 at 6:20 am.

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Re: How to check data type

Oct 18th, 2007

Euhm, I have a similair problem.

I wanna make sure a value entered in a console application is not empty, a number, and and intiger. I just started learning VB, so i came up with this noobish code, what can i do better?

 Help with Code Tags 
 Visual Basic 4 / 5 / 6 Syntax (Toggle Plain Text) 
    Private Sub failsafe(ByVal bericht As String, ByRef cijfer As Integer, ByVal procedure As String) 
        Dim tempVar As String 
        Console.WriteLine(bericht) 
        tempVar = Console.ReadLine 
        'Check for contents 
        If (tempVar <> "") Then 
            'Check for numeretical value 
            If IsNumeric(tempVar) Then 
                cijfer = CByte(tempVar) 
                'Check to see if value is integer 
                If (cijfer >= -2147483648) And (cijfer <= 2147483647) Then 
                    'Procedure that is executed when all creteria are met 
                    procedure() 
                Else 
                    Main() 
                End If 
            Else 
                Main() 
            End If 
        Else 
            Main() 
        End If 
    End Sub
    Private Sub failsafe(ByVal bericht As String, ByRef cijfer As Integer, ByVal procedure As String) 
        Dim tempVar As String 
        Console.WriteLine(bericht) 
        tempVar = Console.ReadLine 
        'Check for contents 
        If (tempVar <> "") Then 
            'Check for numeretical value 
            If IsNumeric(tempVar) Then 
                cijfer = CByte(tempVar) 
                'Check to see if value is integer 
                If (cijfer >= -2147483648) And (cijfer <= 2147483647) Then 
                    'Procedure that is executed when all creteria are met 
                    procedure() 
                Else 
                    Main() 
                End If 
            Else 
                Main() 
            End If 
        Else 
            Main() 
        End If 
    End Sub

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Re: How to check data type

#10

Oct 18th, 2007

•

Originally Posted by WaltP

I think we're getting away from the original question, which was
Doesn't this mean:
I have a number in a text box. How can I tell if I need an Integer or a Long when it's converted from ASCII to binary?

Or am I interpreting this wrong?

How about trying the following way???

 Help with Code Tags 
 Visual Basic 4 / 5 / 6 Syntax (Toggle Plain Text) 
    Dim Value As Double
    Dim IntMaxValue As Integer
    Dim LongMaxValue As Long
 
    IntMaxValue = 32767
    LongMaxValue = 2147483647
 
    Value = CDbl(Text1.Text)
 
    If Value > LongMaxValue Then
        MsgBox "Value is double"
    ElseIf Value > IntMaxValue Then
        MsgBox "Value is long"
    Else
        MsgBox "Value is integer"
    End If
    Dim Value As Double
    Dim IntMaxValue As Integer
    Dim LongMaxValue As Long
    
    IntMaxValue = 32767
    LongMaxValue = 2147483647
    
    Value = CDbl(Text1.Text)
    
    If Value > LongMaxValue Then
        MsgBox "Value is double"
    ElseIf Value > IntMaxValue Then
        MsgBox "Value is long"
    Else
        MsgBox "Value is integer"
    End If