How to Check if The User Write decimal in Textbox

Question

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I need when the user Write for Example : 10.10
I need to Show Error Message :
This textbox Only Integer :
Just Accept Only Integer Number Like 10

private void txtQty_TextChanged(object sender, EventArgs e)
{

}

Posted 24-Apr-15 1:08am

Member 11280947

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3 solutions

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jgakenhe · Answer 1 · 2015-04-24T01:39:00

For Decimal you use Decimal.TryParse and for integers use Int32.TryParse.

C#

private void txtQty_TextChanged(object sender, EventArgs e)
{
	decimal txtbox1;
	if (Decimal.TryParse(txtBoxDecimal.Text, out txtbox1))
	{
		//do something with txtbox1
	}
	else
	{
		lblMessage.Text = "* Not a decimal.";
		return;
	}

	int32 txtbox2;
	bool result = Int32.TryParse(txtBoxInteger.Text, out txtbox2);
	if (result)
	{
		//do something with txtbox2        
	}
	else
	{
		lblMessage.Text = "* Not a number.";
		return;         
	}
}

P Lokeswar Reddy · Answer 2 · 2015-04-24T01:47:00

Solution 2

C#

private void txtQty_TextChanged(object sender, EventArgs e)
        {
            int number;
            bool result = Int32.TryParse(txtQty.Text, out number);
            if (!result)
            {
                MessageBox.Show("Invalid Input");
                txtQty.Text = "";
            }

        }

Posted 24-Apr-15 1:47am

P Lokeswar Reddy

Comments

Member 11280947 24-Apr-15 15:57pm

Thank You

adriancs · Answer 3 · 2015-04-24T02:03:00

Solution 3

Use NumericUpDown control, this will force the user to enter either int or decimal.

To force user enter int value:

C#

NumericUpDown.DecimalPlaces = 0;

To force user enter decimal value:

C#

NumericUpDown.DecimalPlaces = 2;

This will save your effort to validate, verify and filter the user input.

Posted 24-Apr-15 2:03am

adriancs

Comments

Alan N 24-Apr-15 8:34am

The DecimalPlaces property doesn't do quite what we expect. It only controls the display format. Try setting DecimalPlaces = 0 and Increment = 1 and then type 1.5 into the control and press enter. The display will show 2 but the Value is 1.5. The arrows now increment by 1 on the actual value, i.e. 2.5, 3.5, 4.5 and the display shows 3, 4, 5. I spent a long time trying to figure out why the decimal value 3 cast to an int was 2!

adriancs 24-Apr-15 9:23am

If you need 2.5, then use NumericUpDown.DecimalPlaces = 1; NumericUpDown.Increment = 0.5;

Alan N 24-Apr-15 9:49am

My comment was just to make the point that the displayed and actual values can be different and settings DecimalPlaces to zero does not enforce any validation of the actual value. Visually it appears to restrict to integral values but that is just an illusion. For NumericUpDowns where integral values should be enforced I add a ValueChanged event handler and truncate the Value.

Member 11280947 24-Apr-15 15:56pm

Thank You

How to Check if The User Write decimal in Textbox

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How to Check if The User Write decimal in Textbox

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