如何在KeyPress Event中为“，”和“。”设置例外？

Question

Note: This is not about EXCEPTIONS!

I'm trying to make a textbox accept everything but Symbols and Punctations... but I need to allow "," and "." . I'm using:

if (char.IsPunctuation(e.KeyChar) == true)
{
     e.Handled = true;
}

if (char.IsSymbol(e.KeyChar) == true)
{
     e.Handled = true;
}

Is there anyway to make an exception for those two Characters ( , and . ) ?

Answer 1

Check for these characters first:

if(e.KeyChar != ',' && e.KeyChar != '.')
{
    if (char.IsPunctuation(e.KeyChar))
    {
         e.Handled = true;
    }

    if (char.IsSymbol(e.KeyChar))
    {
         e.Handled = true;
    }
}

Note on style: There is no need to compare a boolean to true in order for the branch to be taken.

Answer 2

Try this:

if (char.IsPunctuation(e.KeyChar) && e.KeyChar != ',' && e.KeyChar != '.')
{
     e.Handled = true;
}

if (char.IsSymbol(e.KeyChar) && e.KeyChar != ',' && e.KeyChar != '.')
{
     e.Handled = true;
}

Or you could simply check it before all of that:

if( e.KeyChar != ',' && e.KeyChar != '.')
{
    if (char.IsPunctuation(e.KeyChar) )
    {
         e.Handled = true;
    }

    if (char.IsSymbol(e.KeyChar) )
    {
         e.Handled = true;
    }
}

What it does is checks if the character is punctuation/symbol and ALSO the character is NOT ',' or '.'. Therefor the if statement will not run if the character is a comma or period.