how to multiply value of two textboxs into the third text box at runtime

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1.00/5 (3 votes)

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C#

how to multiply value of two textboxs into the third text box at runtime

Posted 21-Mar-11 5:43am

AAHLONE

Updated 22-Mar-11 13:46pm

Toli Cuturicu

v2

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pankajupadhyay29 21-Mar-11 13:47pm

try to specify maximum things in question like you are doing this in web application and you want to do this without postback etc.

3 solutions

Solution 3

To update the textbox when the user changes the other ones, you just need to copy the code provided by Mika and paste it into a TextChanged event handler:

C#

public YourForm()
{
   InitializeComponent();
   //add the handler for the two input boxes
   textBox1.TextChanged += textbox_TextChanged;
   textBox2.TextChanged += textbox_TextChanged;
}

private void textBox_TextChanged(object sender, EventArgs e)
{
   try
   {
       textBox3.Text = (Decimal.Parse(textBox1.Text) * Decimal.Parse(textBox2.Text)).ToString();
   }
   catch
   {
       //an error occured...
   }
}

Posted 21-Mar-11 6:05am

Olivier Levrey

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pankajupadhyay29 22-Mar-11 0:29am

using TextChanged event will cause to postback the page, i think javascript is solution for achiving this without postback(OP says in comment for solution1 that he want it with out postback)

Olivier Levrey 22-Mar-11 4:48am

OK thanks for your comment.

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Wendelius · Accepted Answer · 2011-03-21T05:48:00

Solution 1

Taken this is WinForms: For example with decimal values use Decimal.Parse Method[^]. For example:

textBox3.Text = (Decimal.Parse(textBox1.Text) * Decimal.Parse(textBox2.Text)).ToString();

Of course you need to add checks, use try catch, possibly use TryParse instead and so on.

Addition:
You can put the code where anywhere you like. For example you can use the text boxes Validating event, KeyUp, KeyDown etc, whatever is feasible.

Posted 21-Mar-11 5:48am

Wendelius

Updated 21-Mar-11 5:59am

v3

Comments

Olivier Levrey 21-Mar-11 11:50am

I voted 5. I just added the missing ToString.

Wendelius 21-Mar-11 11:56am

Thanks :)

AAHLONE 21-Mar-11 12:00pm

i mean to say that as i write the value in textboxes the multiply should automaticaly came third column .

Wendelius 21-Mar-11 12:03pm

Did you read the addition I wrote, use a feasible event and drop the code into it.

Olivier Levrey 21-Mar-11 11:55am

OP said: i want it without pressing any thing

Wendelius 21-Mar-11 12:02pm

Yes, thanks, I noticed. I made an addition to the solution. Hopefully the OP will clarify the requirements a bit more if this approach isn't suitable.

AAHLONE 21-Mar-11 12:49pm

i want it without postback

Ed Nutting 21-Mar-11 13:21pm

Aahh.. you mean to say you are using web based application not Windows Forms Application. In that case, in your Page Load event (presumably where you fill the two texboxes with the values) or wherever you fill the two texboxes place Mika's code as well. This will fill in all three without postback. If you want the user to fill in the boxes and then have the third box filled in without using postback you will have to use javascript. Try using W3Schools.com to help you, they are very good with very good tutorials to get you started and they list all the features/standards of html, javascript, css and the rest :) Hope this helps, Ed

Wendelius 21-Mar-11 15:26pm

So it's ASP, not WinForms. In that case as EdMan196 already stated if you need to do the calculation while user enters the input, you'll need a small jJavaScript to handle that on client side.

pankajupadhyay29 · Accepted Answer · 2011-03-21T07:46:00

To do this without postback you should use javascript--

Java

function updateValue()
{
  var val1=document.getElementByID("<%=textbox1.ClientID%>").value;
  var val2=document.getElementByID("<%=textbox2.ClientID%>").value;
  document.getElementByID("<%=textbox3.ClientID%>").value=parseFloat(val1)*parseFloat(val2);
}

now you can call this at any javascript event of your need i am calling this at blur-

write this on pageload

C#

textbox1.Attribute.Add("onblur","updateValue()");
textbox2.Attribute.Add("onblur","updateValue()");

--Pankaj

how to multiply value of two textboxs into the third text box at runtime

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