textBox & String

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John. S. - 09 Apr 2007 18:17 GMT

Hi,

1) How can I convert a Text property (textBox1->Text) or a String to an
integer?
(There is a "ToInt32()" member function but I couldn't
use it. int i = textBox1->Text.ToInt32(???);

2) I'd like to display in a loop:
abc 0 def
abc 1 def
abc 2 def
abc 3 def
abc 4 def

What I've found is:
for(int i = 0; i < 5; i++)
MessageBox::Show(String::Concat("abc ", i.ToString(), " def");

Is there an easier way to display that?
(I mean the Borland way: ShowMessage("abc " + IntToStr(i) + " def"); )

3)I'd like to add multiple lines to a textBox at runtime. The MultiLine
property of the textBox is true.
Line0
Line1
Line2
Line3...
How do I use the textBox1->Lines or textBox1->Lines->Item[i] for this
purpose ?

Thanks...

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pvdg42 - 10 Apr 2007 04:12 GMT

> Hi,
>
> 1) How can I convert a Text property (textBox1->Text) or a String to an
> integer?
> (There is a "ToInt32()" member function but I couldn't
> use it. int i = textBox1->Text.ToInt32(???);

Addressing your first question,

http://msdn2.microsoft.com/en-us/library/sf1aw27b.aspx

Note that you must pass the string to be converted as the argument and that
the return type is int.

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Ben Voigt - 10 Apr 2007 14:38 GMT

>> Hi,
>>
[quoted text clipped - 9 lines]
> Note that you must pass the string to be converted as the argument and
> that the return type is int.

Oh yuck. What's the point of having namespaces and classes if you throw
everything into one huge "Convert" mess.

Use either System::Int::Parse or System::Int::TryParse:

int i;
try {
i = System::Int::Parse(textBox1->Text);
}
catch (FormatException^ e) {
// not a valid number
}

or

int i;
if (!System::Int::TryParse(textBox1->Text, i)) {
// not a valid number
}

The second one is more efficient unless the frequency of bad inputs is very
very very low.

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John. S. - 11 Apr 2007 12:45 GMT

> Use either System::Int::Parse or System::Int::TryParse:
>
[quoted text clipped - 15 lines]
> The second one is more efficient unless the frequency of bad inputs is
> very very very low.

calling
System::Int::Parse(textBox1->text);
gives a compile error:
error C2039: 'Int' : is not a member of 'System'

???

Reply to this Message

Ben Voigt - 11 Apr 2007 14:08 GMT

>> Use either System::Int::Parse or System::Int::TryParse:
>>
[quoted text clipped - 20 lines]
> gives a compile error:
> error C2039: 'Int' : is not a member of 'System'

Sorry, it's Int32 (or Int16 or Int64 or UInt32 or ..., but Int32 corresponds
to C++'s int).

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textBox & String

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