TEdit entry validation 2

[Dhagaxtuur]

I need help validating entry of TEDIT->TEXT. How do I make sure user enters numbers with decimal points. Example: 29.95. If the user enters char, I want display error message or ignore it. Please help. Thanks

 

[Totte]

In the TDEIT->OnKeyPress event you can get the key pressed BEFORE it's entered. If you don't like the key just alter the 'Key' variable to 0 (zero) and it will "dissapear".

if(!strchr("0123456789.\r\n\x08",Key)) Key = 0;
Means: if key NOT in 0,1,2,3,4,5... set key to zero.
You might want to take in backspace keys and such to allow some edition.
\x08 = backspace
\r = return
\n = linefeed

Totte
Keep making it perfect and it will end up broken.

 

[Dhagaxtuur]

Thank you very much Totte. That was the solution. Great

 

[Bernie2]

How would you check for only two decimal places.

Thanks. Bernie.

 

[butthead]

it might require some fine tuning but I
got it to work OK.

int precision = 2;
int precision_count = 0;
bool stop = false;

void __fastcall Ttable::Edit2KeyPress(TObject *Sender, char &Key)
{
    if (stop)
        Key = 0;
    else if(!strchr("0123456789.\r\n\x08",Key))
        Key = 0;
    else if (Key == '.')
    {
        if (precision_count == 0)
            precision_count++;
        else
            Key = 0;
    }
    else if (precision_count > 0)
        precision_count++;  

    if (precision_count == precision + 1)
        stop = true; 
}

TC

 

[Bernie2]

Thanks Butthead,

This works well except once stop is true you cant arrow back and modify the entry.

Maybe if i clear the field when they backspace and reset the counters.

Thanks Bernie.

 

[butthead]

its a start.

it can be adapted to fit many specific instances.

you could also put

if(Key == '\b')

at the beginning to handle the backspace operation.
remember to handle the precision counter to decrement
this value when necessary.

the arrow key I think will be handled in the onKeydown
or up methods as you will test for the virtual key codes
there.

TC

 

[Bernie2]

Thanks TC (Top Cat)

Yes its a great start and i should be able to sort something out.

Thanks Again