validate a textbox using C#

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1.50/5 (2 votes)

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Good evening to everyone............
I just need a code to validate a textbox that should not allow more than 200 characters.

Can anyone step forward

Posted 28-Feb-12 2:07am

vivekx2

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Shahin Khorshidnia 28-Feb-12 8:14am

Please Tag your question. WinForm? ASP.Net? WPF? ....?

4 solutions

Solution 5

Another solution would be to use the .Validating event from the Control. You can than use a ErrorProvider-Control to show the user what he is doing wrong.

http://msdn.microsoft.com/en-us/library/system.windows.forms.control.validating.aspx[^]

Posted 11-Jun-12 2:33am

neyerMat

Solution 3

set MaxLength property of the textbox to 200

Posted 1-Mar-12 6:07am

sai kv

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Shahin Khorshidnia · Accepted Answer · 2012-02-28T02:12:00

Solution 1

Hello,

Set it's MaxLenght to 200

Posted 28-Feb-12 2:12am

Shahin Khorshidnia

#realJSOP · Accepted Answer · 2012-02-28T02:13:00

Solution 2

Handle the TectChanged event, and do something like this:

C#

TextBox ctrl = sender as TextBox;
if (ctrl.Length > 200)
{
    ctrl.Text = ctrl.Text.Substring(0,200);
}
labelCtrl.Text = string.Format("{0} of 200 characters", ctrl.Text.Length);

Posted 28-Feb-12 2:13am

#realJSOP

Updated 1-Mar-12 3:23am

v2

Comments

vivekx2 28-Feb-12 8:17am

thanks for ur support....but i need to display the error message in label below the textbox....
so how to call the label in your coding...

#realJSOP 1-Mar-12 9:24am

Seriously? You couldn't figure that out on your own? Answer updated.

Member 8385328 1-Dec-15 19:02pm

Why should not I do it like this (without TextBox ctrl = sender as TextBox;):

private void textBox1_TextChanged(object sender, EventArgs e)
{

if (textBox1.TextLength > 30)
{
textBox1.Text = textBox1.Text.Substring(0, 30);
}
labelCtrl.Text = string.Format("{0} of 200 characters", textBox1.Text.Length);
}