Number Validation In Textbox (No Numbers)

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Hi, What I am trying to do is have a textbox that does not permit any numbers in. I currently have the below code but it is giving me a error "operator || cannot be applied" between the "0" and the "1". I was wondering how I can fix this error and make the code do what i would like it to do please.

C#

if (TextBox1.Text == "0" ||"1"|| "2"|| "3"|| "4"|| "5" || "6"|| "7"|| "8"|| "9")
{
    MessageBox.Show("No Numbers Allowed For name");
}

Posted 19-Mar-14 8:24am

Member 9665875

Updated 19-Mar-14 20:35pm

VICK

v2

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Comments

Matt T Heffron 19-Mar-14 14:47pm

It isn't entirely clear what the restriction is:
the input cannot be any single digit number, but multiple digit numbers are OK?
(that is what your code above looks like it is attempting, as well as Solution 1)
OR
the input cannot be only digits (like Solution 3 will detect)
OR
the input cannot contain any digits?
Can you clarify the restriction?

Member 9665875 19-Mar-14 17:08pm

the textbox must only contain letters and not numbers in any part of the textbox

7 solutions

Solution 5

A variation on Marcin's Solution 4:

C#

private void textBox1_KeyPress(object sender, KeyPressEventArgs e)
{
    if (char.IsDigit(e.KeyChar))
    {
        e.Handled = true;
    }
}

No array required!

Posted 19-Mar-14 12:24pm

Matt T Heffron

Comments

Marcin Kozub 19-Mar-14 19:09pm

Good point :)

Solution 1

Try

C#

if (TextBox1.Text == "0" ||TextBox1.Text == "1"|| TextBox1.Text == "2"|| TextBox1.Text == "3"|| TextBox1.Text == "4"|| TextBox1.Text == "5" || TextBox1.Text == "6"|| TextBox1.Text == "7"|| TextBox1.Text == TextBox1.Text == "8"|| TextBox1.Text == "9")
{
    MessageBox.Show("No Numbers Allowed For name");
}

You could use RegEx instead.

C#

if ( !Regex.Match ( TextBox1.Text, "^[0-9]+$" ).Success ) {
      // TODO.
}

Posted 19-Mar-14 8:28am

Abhinav S

Comments

Member 9665875 19-Mar-14 16:58pm

my only problem with the top solution which i would like to use, is it checks the first character in the textbox and not the entire textbox how can i change this so the if loop condition applies for the whole textbox

Solution 6

u can use key press event (vb) :

VB

e.Handled = Not Char.IsDigit(e.KeyChar)

Posted 19-Mar-14 13:52pm

muhannadcs

Solution 7

Use FilteredTextBox Extender
Try this:

C#

<asp:textbox id="TextBox1" runat="server"></asp:textbox>
<cc1:filteredtextboxextender id="FilteredTextBoxExtender1"  runat="server" filtertype="Alphabets" TargetControlID="TextBox1"/>
</cc1:filteredtextboxextender>

Posted 19-Mar-14 20:45pm

Tom Marvolo Riddle

Updated 19-Mar-14 20:47pm

v2

Solution 2

Use Simple Javascript Code :

C#

<script type="text/javascript" language="javascript">

function AcceptAlphabhetsOnly(event, allowPeriod) {
            var keyCode = event.which ? event.which : event.keyCode;
            if (keyCode < 48 || keyCode > 57) {
                return true;
            }
            if ((keyCode >= 65 && keyCode <= 90) || (keyCode >= 97 && keyCode <= 122) || (keyCode == 32) || ((allowPeriod == true) && (keyCode == 46))) {
                return true;
            }
            return false;
        };

    </script>

On Textbox :

C#

<asp:textbox id="txtFName" runat="server" onkeypress="return AcceptAlphabhetsOnly(event, false);" />

Posted 19-Mar-14 8:30am

Kishor Khatri

Updated 19-Mar-14 20:38pm

v3

Comments

Marcin Kozub 19-Mar-14 17:05pm

Question concerns C# not JS...

Solution 3

Rather I'd have used int.TryParse[^].

C#

public void checkText(string value)
{
    int number;
    bool result;
    
    result = int.TryParse(value, out number);
    
    if (result)  
    {
        MessageBox.Show("No Numbers Allowed For name");
    }
}

-KR

Posted 19-Mar-14 8:34am

Krunal Rohit

Comments

Marcin Kozub 19-Mar-14 16:53pm

Your code will not work if user enter somtehing like this: Krunal0...

Krunal Rohit 19-Mar-14 16:55pm

That is a different thing.
My point is, instead of using multiple if, we can get some advantage of framework as well..

And have you tried this code ??

-KR

Marcin Kozub 19-Mar-14 17:03pm

I don't have to try your code, because it's obvious that it will not work when user enter text like 'Krunal0'.

Question is very clear, OP doesn't want to user enter any digit on text. Your code displays message only when entered text is a number.

Try to read question more carefuly.

I've posted Solution #4. You should take a look.

Member 9665875 19-Mar-14 17:19pm

this is what i would like though

Krunal Rohit 20-Mar-14 2:58am

"Accept Solution", if this would have helped.

-KR

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Marcin Kozub · Accepted Answer · 2014-03-19T10:55:00

You can use KeyPress event of TextBox control:

C#

private void textBox1_KeyPress(object sender, KeyPressEventArgs e)
{
    char[] charsNotAllowed = {'0', '1', '2', '3', '4', '5', '6', '7', '8', '9'};
    if (charsNotAllowed.Contains(e.KeyChar))
    {
        e.Handled = true;
    }
}

Hope it helps you :)