numeric only textbox

Hughesie78 · December 3rd, 2007, 10:44 AM

How can i make sure a user can only enter numerical data onto a text box(including a decimal point).

dparsons · December 3rd, 2007, 10:46 AM

Use a regular expression.

http://www.google.com/search?source=...lar+expression
http://www.google.com/search?hl=en&s...lar+expression

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Hughesie78 · December 4th, 2007, 10:19 AM

Here is my aspx code, I have 3 text boxes, the 2nd and 3rd will calculate the total on the text changed event, the first one will when there is no âonkeyupâ event, howvere the onkeyup event is used to make sure that no text is entered, how can I make it both events work?>

<%@ Page Language="C#" AutoEventWireup="true" CodeFile="totals.aspx.cs" Inherits="totals" %>

<!DOCTYPE html PUBLIC "-//W3C//DTD XHTML 1.0 Transitional//EN" "http://www.w3.org/TR/xhtml1/DTD/xhtml1-transitional.dtd">
<html xmlns="http://www.w3.org/1999/xhtml">
<head runat="server">
    <title>total</title>

        <script type="text/javascript" language="javascript">
function ValidateText(i)
{
    if(i.value.length>0)
    {
    i.value = i.value.replace(/[^\d]+/g, '');
    }
}
</script>
</head>
<body>
    <form id="form1" runat="server">
<asp:Button runat=server ID=btnd />
        <br />
        <br />
        Value:
        <asp:TextBox ID="TextBox1" onkeyup = "ValidateText(this)" runat="server" OnTextChanged="TextBox1_TextChanged" AutoPostBack=true>0.00</asp:TextBox>
        <asp:CompareValidator ID="cfvTest" runat="server" ControlToValidate="TextBox1" ErrorMessage="* Must be numeric"
            SetFocusOnError="True" Type="Double" Width="168px"></asp:CompareValidator>
        <br />
        Value:
        <asp:TextBox ID="TextBox2" runat="server" OnTextChanged="TextBox1_TextChanged" AutoPostBack=true>0.00</asp:TextBox>
        <asp:CompareValidator ID="CompareValidator1" runat="server" ControlToValidate="TextBox2"
            ErrorMessage="* Must be numeric" SetFocusOnError="True" Type="Double" Width="168px"></asp:CompareValidator>
        <br />
        Value:
        <asp:TextBox ID="TextBox3" runat="server" OnTextChanged="TextBox1_TextChanged" AutoPostBack=true>0.00</asp:TextBox>
        <asp:CompareValidator ID="CompareValidator2" runat="server" ControlToValidate="TextBox3"
            ErrorMessage="* Must be numeric" SetFocusOnError="True" Type="Double" Width="168px">
        </asp:CompareValidator>
        <br />
        Total    :<asp:Label ID="lbl_1" runat="server" Width="144px"></asp:Label>
        <asp:TextBox ID=txt_total runat=server></asp:TextBox>
    </form>
</body>
</html>

dparsons · December 4th, 2007, 01:21 PM

TextChanged will not be raised until the Text has changed in the control AND the control loses focus.

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Hughesie78 · December 5th, 2007, 08:00 AM

ok, can you suggest any other way around this apart from using 'ontextchanged'?

dparsons · December 5th, 2007, 10:01 AM

Ya, I would use a RegularExpressionValidator Server control. I don't understand what you are trying to do with this though:

<asp:CompareValidator ID="cfvTest" runat="server" ControlToValidate="TextBox1" ErrorMessage="* Must be numeric"
SetFocusOnError="True" Type="Double" Width="168px"></asp:CompareValidator>

you are not comparing TextBox1 to anything. In any event, as I said, you could use a regularExpressionValidator to enforce your RegularExpression. (The method you have demonstrated above can easily be gotten around if I come to your website and disable JavaScript)

hth.

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Hughesie78 · December 5th, 2007, 10:17 AM

Hi, The regular expression works fine, it causes an error when text is entered, BUTâ¦. My real problem is that I have a method that is fired from the ontextchanged event, this method calculates a running total, and displays it in another control, works fine when I have entered numbers, but when I enter text, it causes and error before it gets to display the validation errorâ¦ here is my codeâ¦
Aspx:
<asp:TextBox ID="TextBox4" runat="server" OnTextChanged="TextBox4_TextChanged" AutoPostBack=true></asp:TextBox> <asp:RegularExpressionValidator ID="RegularExpressionValidator1" runat="server" ControlToValidate="TextBox4" ErrorMessage="* Please input a number!" ValidationExpression="^\d{1,7}(\.\d{1,2})?$"></asp:RegularExpressionValidator>

Codebeihnd:

protected void TextBox4_TextChanged(object sender, EventArgs e)
  {
   double total = double.Parse(TextBox4.Text) ;
      lbl_1.Text = total.ToString();
    txt_total.Text = total.ToString();
  }

Is there anyway around that that I can prevent the TextBox4_TextChanged method being called if the field has text in it withou having to add a button which only caclulates after all validations are done, I want it to calculate a running totalâ¦

dparsons · December 5th, 2007, 10:58 AM

I would do something like this since you want to rely on server events:

Code:

//matches a floating point number in the 
//format N.DD
public bool isFloat(string Value)
{
   System.Text.RegularExpressions.Regex ex = new Regex("^([0-9]+(\\.[0-9][0-9]))$");
   return ex.Match(Value).Success;
}
protected void TextBox_TextChanged(object sender, EventArgs e)  
{
   TextBox txt = (TextBox)sender;
   if(!isFloat(txt.Text))
   {
     return;
   }
   else
   {      
   double total = double.Parse(txt.Text) ;   
      lbl_1.Text = total.ToString();    
    txt_total.Text = total.ToString();  
   } 
  }

I modified your TexTChanged code so that you only need one event to handle all of your textboxes textchanged event hence the line:
TextBox txt = (TextBox)sender;

hth

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Read this if you want to know how to get a correct reply for your question:
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Wrox Books 24 x 7
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