My Invalid Character Code does not validate

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Good Day,

I am creating a web form and I am trying to validate some textboxes e.g. I don't want the end user to insert letters in ID text box..

Here are my codes below and please advise me if I am using an old method

C#

protected void txtID_TextChanged(object sender, EventArgs e)
       {
           foreach (char cr in txtID.Text)
           {
               if (char.IsDigit(cr) == false)
               {
                   Console.Write("Invalid Charactor"","Error Message")         

               }

           }

I have double click the text box and started my coding.....

Posted 5-Jun-13 23:06pm

Nkhanedzeni

Updated 5-Jun-13 23:13pm

Jameel VM

v4

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Jameel VM 6-Jun-13 5:12am

what validation you need?only number?

Nkhanedzeni 6-Jun-13 5:16am

only numbers on ID textbox

2 solutions

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Ahmed Bensaid · Answer 1 · 2013-06-05T23:39:00

Solution 1

Hello,

You may use a custom validator control.
Have a look on this : CustomValidator, contrôle - MSDN - Microsoft

Posted 5-Jun-13 23:39pm

Ahmed Bensaid

v2

Comments

Nkhanedzeni 6-Jun-13 5:44am

Thanks....do you have any idea on what will be the problem with my coding?

Ahmed Bensaid 6-Jun-13 6:06am

You're welcome.
You need to initialize the AutoPostBack parameter of the TextBox to True. And press enter when you finish writing in this TextBox. To generate a PostBack to the server.
Can you explain me what do you want to do accurately ?
Cause, if you want some live validation when the user is writing in the TextBox, you'll need some client code (JavaScript).
And if your application is an ASP.NET application, why are you using Console.Write() ?

Nkhanedzeni 6-Jun-13 6:21am

It is just for learning purpose since i knew by coding

Ahmed Bensaid 6-Jun-13 6:27am

Ok, so you should use the MSDN examples of the tutorial I gave you ;)

Nkhanedzeni 6-Jun-13 6:29am

so i must not use Console.Write()?

Nkhanedzeni 6-Jun-13 6:25am

why are you using Console.Write() ? it does not allows me to write Messagebox likke on windows forms

Ahmed Bensaid 6-Jun-13 6:30am

MessageBox (which is available in WinForms) is not available for ASP.NET.
And Console.Write() is used by Console Applications.
When you are using an ASP.NET web application, you should use alert() JavaScript function to popup a window with a message.

Nkhanedzeni 6-Jun-13 6:32am

From the code below...show me how to write it

protected void txtID_TextChanged(object sender, EventArgs e)
{
foreach (char cr in txtID.Text)
{
if (char.IsDigit(cr) == false)
{
Console.Write("Invalid Charactor"","Error Message")

}

}

Jameel VM · Answer 2 · 2013-06-05T23:49:00

Solution 2

Try this

VB

<asp:CompareValidator runat="server" Operator="DataTypeCheck" Type="Integer"
 ControlToValidate="ValueTextBox" ErrorMessage="Value must be a whole number" />

Hope this helps

Posted 5-Jun-13 23:49pm

Jameel VM

Comments

Nkhanedzeni 6-Jun-13 6:02am

Thanks let me try this....i will get back to you soon

Nkhanedzeni 6-Jun-13 6:16am

thanks......working

Jameel VM 6-Jun-13 6:32am

Please mark it as a answer