Alphanumeric Password

Question

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I want to restrict my user to strictly input alphanumeric password only to open my application. Please provide c# code or algorithm for the same.

Posted 31-Jan-11 23:23pm

sk saini

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4 solutions

Solution 4

Just a note: what you want is considered as unsafe practice even in user's preferences. Look at any article on password strength. Pravin's answer is probably very adequate.

While other works tries to offer ways of encouraging users to create stronger passwords or, very typically, limits passwords to stronger ones by denying simple ones, you do exactly the opposite!

This is up to you, of course, but you're not helping your customers at all. It would be much, much, way to much better to allow them using any passwords at all.

Thank you for your understanding.

—SA

Posted 1-Feb-11 8:58am

Sergey Alexandrovich Kryukov

Updated 1-Feb-11 14:09pm

v2

Comments

Sergey Alexandrovich Kryukov 2-Feb-11 3:16am

I would say, this vote of "3" is a bright manifestation of stupidity, inability to understand a good advice, it it is contradict the preoccupation, no matter how wrong.
Sorry, for you, loser!
--SA

Manas Bhardwaj 2-Feb-11 4:02am

+5 SA.

Sergey Alexandrovich Kryukov 2-Feb-11 4:08am

Thank you, Manas.
--SA

Solution 2

In the TextBox Event Select TextChainged Event And then place this code there
Note:-Replace Textbox Name Here

C#

string charactersAllowed = "0123456789";
string theText = TEXTBOXNAME.Text;
string Letter = null;
int SelectionIndex = TEXTBOXNAME.SelectionStart;
int Change = 0;
for (int x = 0; x <= TEXTBOXNAME.Text.Length - 1; x++) {
    Letter = TEXTBOXNAME.Text.Substring(x, 1);
    if (charactersAllowed.Contains(Letter) == false) {
        theText = theText.Replace(Letter, string.Empty);
        Change = 1;
    }
}
TEXTBOXNAME.Text = theText;
TEXTBOXNAME.Select(SelectionIndex - Change, 0);

CHECK OUT This it Realy Works.....
All the Best ....

Posted 31-Jan-11 23:32pm

harinath_23

Comments

sk saini 1-Feb-11 6:24am

I applied this code but it doesn't accepts any letter in Textbox.

sk saini 1-Feb-11 6:25am

Actually its taking input letter but simultaneously deleting the same.

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shakil0304003 · Accepted Answer · 2011-01-31T23:30:00

Solution 1

Register Textbox KeyPressEvent

private void textBox1_KeyPress(object sender, KeyPressEventArgs e)
{
// Allows only Alpha-Numeric’s
if (!(Char.IsLetter(e.KeyChar) || Char.IsDigit(e.KeyChar) || Char.IsControl (e.KeyChar)))
e.Handled = true;
}

Posted 31-Jan-11 23:30pm

shakil0304003

Comments

sk saini 1-Feb-11 6:45am

Thanks, its working.

shakil0304003 1-Feb-11 6:48am

Welcome.

Pravin Patil, Mumbai 1-Feb-11 10:12am

Great solution shakil..
Simple but effective.

Sergey Alexandrovich Kryukov 1-Feb-11 15:06pm

Correct; I voted "5". However the purpose is completely wrong, I think.
Please see my answer.
Best,
--SA

fjdiewornncalwe 1-Feb-11 15:28pm

Agreed. +5 because the answer is 100% for the OP's question, but I too have serious questions about the theory behind doing this.

Sergey Alexandrovich Kryukov 1-Feb-11 16:15pm

That's why I voted for Pravin's answer first.
--SA

Pravin Patil, Mumbai · Accepted Answer · 2011-01-31T23:47:00

Solution 3

Refer Password Strength Control[^]

It has an excellent code to measure password strength.
I hope this helps.

All the best.

Posted 31-Jan-11 23:47pm

Pravin Patil, Mumbai

Comments

Sergey Alexandrovich Kryukov 1-Feb-11 14:59pm

You're offering just the opposite to what OP wants; and I totally agree with you! - my 5.
I referenced your answer in mine -- please see.
--SA

Pravin Patil, Mumbai 2-Feb-11 0:53am

Thanks SA.