How Can I Check Whether A Textbox Contains A Decimal Point In The Starting In C#

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Hi,

i have a text box which accepts only numeric and decimal points. so how can i display an alert message when a textbox only contains a decimal point without any numeric value on click of OK button in C#?

Posted 10-Mar-14 23:47pm

Member 10593922

Updated 15-Sep-20 5:07am

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Karthik_Mahalingam · Answer 1 · 2014-03-10T23:59:00

Solution 2

C#

if (TextBox1.Text.Split('.').Length > 1)
{    // alert message for multiple dots
}
           if (TextBox1.Text.Trim() == ".")
           {
               // alert message for only dot
           }

Posted 10-Mar-14 23:59pm

Karthik_Mahalingam

Comments

Member 10593922 11-Mar-14 8:28am

thank u for the reply. plz can u tel me how can i restrict user from entering max of only one digit after the decimal point in the texbox:

like .9--> valid
.56-->not valid

Karthik_Mahalingam 11-Mar-14 8:30am

you can handle it in key press event

Member 10593922 11-Mar-14 8:35am

can u plz write sample code?

OriginalGriff · Answer 2 · 2014-03-10T23:50:00

Solution 1

Try:

C#

if (myTextBox.Text.Trim() == ".")
   {
   ...
   }

Posted 10-Mar-14 23:50pm

OriginalGriff

Comments

Ravi Bhavnani 11-Mar-14 8:32am

I think the call to .Trim() is extraneous (and dangerous if myTextBox.Text is null) since the input filter guarantees the TextBox will contain only the period or numeric characters.

/ravi

OriginalGriff 11-Mar-14 8:49am

The Textbox.Text property can never be null - if you use Reflector to examine the MS code, it specifically checks foe a null value and returns string.Empty instead.

The Trim is probably irrelevant, yes, but it just makes it clearer and doesn't take a lot of extra time. (And it works even if someone forgets to make sure that space is excluded later!)

Ravi Bhavnani 11-Mar-14 10:15am

> specifically checks foe a null value and returns string.Empty
Ah. Thanks!

/ravi

OriginalGriff 11-Mar-14 10:43am

Welcome!

GauravSatpute · Answer 3 · 2014-03-11T20:25:00

C#

namespace WindowsFormsApplication1
{
    public partial class Form1 : Form
    {
        public Form1()
        {
            InitializeComponent();
        }

        private void button1_Click(object sender, EventArgs e)
        {
            Regex r1 = new Regex(@"^.$");
            if ((r1.IsMatch(textBox1.Text)))
            {
                MessageBox.Show("plz enter Valid value");
               //if and only if text box contains only dot without numeric value. 
            }

        }
    }
}