C # how to prevent special characters

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Hello,
I just created this condition to block special characters.
it works, but can we make it simpler?
Who can bring me a better solution?

What I have tried:

C#

private void textbox1_KeyPress(object sender, KeyPressEventArgs e)
{
    if (e.KeyChar == '>' || e.KeyChar == '<' || e.KeyChar == '@' || e.KeyChar == '{' || e.KeyChar == '}' || e.KeyChar == '[' || e.KeyChar == ']' || e.KeyChar == '#' || e.KeyChar == '&' || e.KeyChar == '(' || e.KeyChar == ']' || e.KeyChar == '/' || e.KeyChar == '|' || e.KeyChar == '*' || e.KeyChar == '-' || e.KeyChar == '+' || e.KeyChar == '$' || e.KeyChar == '%' || e.KeyChar == '~' || e.KeyChar == 92)
    {
        e.Handled = true;
    }
}

Posted 8-Apr-20 1:45am

LSB71

Updated 8-Apr-20 2:35am

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OriginalGriff · Accepted Answer · 2020-04-08T02:01:00

Try:

C#

private const string NotAllowed = @"><@{}[]#&()/|*-+$%~\";
private void textbox1_KeyPress(object sender, KeyPressEventArgs e)
    {
    if (NotAllowed.Contains(e.KeyChar))
        {
        e.Handled = true;
        }
    }

Or even:

C#

private const string NotAllowed = @"><@{}[]#&()/|*-+$%~\";
private void textbox1_KeyPress(object sender, KeyPressEventArgs e)
    {
    e.Handled = NotAllowed.Contains(e.KeyChar);
    }

Maciej Los · Accepted Answer · 2020-04-08T02:35:00

Solution 2

Another way is to use ErrorProvider Component Overview - Windows Forms | Microsoft Docs[^]. You can validate value entered in a textbox and display error icon near the textbox.

Display Error Icons for Form Validation with ErrorProvider Component - Windows Forms | Microsoft Docs[^]
Do not forget to clear error[^] after successful validation.

Posted 8-Apr-20 2:35am

Maciej Los

Comments

LSB71 10-Apr-20 2:01am

Thank you very much, excellent I learn it every day

Maciej Los 10-Apr-20 2:18am

You're very welcome.