CODEWITHSUNDEEP
c#asp.netregexvalidation
user4221591
user4221591

Reputation: 2150

asp validation for multiple spaces between strings

I've a textbox for name field where I've used asp validation for proper name format. I want to validate multiple spaces between the strings. How can I do that? The leading and trail spaces are removed by trim() function but how can I validate multiple spaces between the strings? like

multiple    spaces

no   space

My validation code::

<label>
    <span>Full name</span>
    <input type="text" id="txt_name" runat="server" required="required"/>      
    <asp:RegularExpressionValidator ID="rev_txt_name" runat="server" ControlToValidate="txt_name" ForeColor="Red" 
    ErrorMessage="Invalid name!" SetFocusOnError="True" ValidationExpression="^[a-zA-Z'.\s]{2,50}"></asp:RegularExpressionValidator>

</label>

Upvotes: 1

Views: 476

Answers (1)

Wiktor Stribiżew
Wiktor Stribiżew

Reputation: 626747

The pattern you are using allows matching whitespace anywhere inside the string and any occurrences, consecutive or not, since it is part of a rather generic character class. You need to use a grouping and quantify it accordingly:

^(?=.{2,50}$)[a-zA-Z'.]+(?:\s[a-zA-Z'.]+)*$

Note that the (?=.{2,50}$) lookahead requires the whole line to be of 2 to 50 chars long.

See the regex demo.

Details:

  • ^ - start of string
  • (?=.{2,50}$) - a positive lookahead requiring any 2 to 50 chars other than a newline up to the end of the string
  • [a-zA-Z'.]+ - 1+ letters, single quote or dot chars
  • (?: - a non-capturing group start:
    • \s - 1 whitespace
    • [a-zA-Z'.]+ - 1+ letters, single quote or dot chars
  • )* - zero or more (*) occurrences
  • $ - end of string

Upvotes: 1

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