Validation for Numeric with decimal

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2.00/5 (1 vote)

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Hi guys

I want to validate a text box value, I should allow users to enter values like
1,
1.5,
2,
2.5

it should not take other then 0 or 5 after decimal,

it might be like 10000.5 it should allow.

Advance thanks

Vishwa

Posted 5-Dec-12 16:38pm

VishwaKL

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Sergey Alexandrovich Kryukov · Answer 1 · 2012-12-05T16:43:00

Solution 1

Use the method System.Decimal.TryParse; if it returns true, the string is valid as a decimal representation:
http://msdn.microsoft.com/en-us/library/system.decimal.tryparse.aspx[^].

After that, take parsed value and additionally check up for required range or any other constraint.

[EDIT]

OK, for client side, this is a JavaScript variant. Checking up if the numeric value is valid is more tricky:

JavaScript

function isValidFloat(stringValue) {
    value = parseFloat(stringValue); // will return NaN if invalid
    return (value == value); // check value for NaN
}

Note: there is not "decimal", only floats and integers.

When this is done, check for your constraints the same way.

—SA

Posted 5-Dec-12 16:43pm

Sergey Alexandrovich Kryukov

Updated 5-Dec-12 18:27pm

v3

Comments

VishwaKL 5-Dec-12 22:49pm

I want to validate on client side, your answer will help to validate on server side,

Sergey Alexandrovich Kryukov 6-Dec-12 0:10am

Well, right... can you find analogous approach in JavaScript, or you will need help? This is just a matter of reading documentation...
--SA

VishwaKL 6-Dec-12 0:14am

Ya i need help for this, i tried with java script mine giving validation but it accept

1.1,1.2---- till 1.5 for all numbers so

Sergey Alexandrovich Kryukov 6-Dec-12 0:27am

OK, please see the updated answer, after [EDIT].
You could easily find it and experiment by yourself.
--SA

RahulRana723 · Answer 2 · 2012-12-05T17:46:00

Use This Code:

XML

<html xmlns="http://www.w3.org/1999/xhtml">
<head runat="server">
    <title></title>
</head>
<body>
    <form id="form1" runat="server">
    <div>

    </div>
    <asp:TextBox ID="TextBox1" runat="server"></asp:TextBox>
    <asp:CompareValidator ID="CompareValidator1" runat="server"
        ControlToValidate="TextBox1" ErrorMessage="CompareValidator" Type="Double">Enter Decimal Value</asp:CompareValidator>
        <asp:Button ID="button1" Text="validate" runat="server"/>
    </form>
</body>
</html>