Validation on texbox. regulaexpression?

Question

in my webapplication i have user registration page, in that one textbox contain House No: user has to enter houseno in that textbox. i that user can enter all numarics or all alphabets or all alphanumarics but not all special characters how can i restrict the user not to enter all special characters like user can enter

123455 or abcdef or 12abcdef

but not

&&&&&& or

or

@@@@ or * user should not enter the specail charecters give me some solution thank u

Answer 1

I think that the regular expression you need is (\w|\d)+

EDIT: \w already includes digits, so: \w+

Answer 2

simply ^\w+$

• ^ indicates the start of the string the regex pattern is applied to

• \w matches letters, digits and underscores.

• + matches one or more occurrences (in this case applied to letters, digits and underscores)

• $ indicates the end of the string the regex pattern is applied to

If you didn't want underscores matched then

^[a-zA-Z0-9]+$

If the field was optional, then you may want to use * in place of + as this matches zero or more occurrences.

Answer 3

The standard way to achieve this in asp.net is to use a RegularExpressionValidator control. A simple example is as follows:

    <asp:Label runat="server" ID="HouseNoLabel" Text="House No." AssociatedControlID="HouseNoTextBox" />
    <asp:TextBox runat="server" ID="HouseNoTextBox" />
    <asp:RegularExpressionValidator runat="server" ID="HouseNoValidator" ControlToValidate="HouseNoTextBox"
    ErrorMessage="* only alphanumeric characters are allowed" ValidationExpression="[\w]+" />

If you would like to stop a user from entering invalid values altogether, take a look at the MaskedEdit control from the Ajax Toolkit http://www.asp.net/ajax/AjaxControlToolkit/Samples/