Unit-4. Topic-1 ASP.NET VALIDATION CONTROLS:-

Transcription

1 Unit-4 Topic-1 ASP.NET VALIDATION CONTROLS:- ASP.Net validation controls validate the user input data to ensure that useless, unauthenticated or contradictory data don.t get stored. ASP.Net provides the following validation controls: 1. RequiredFieldValidator 2. RangeValidator 3. CompareValidator 4. RegularExpressionValidator 5. CustomValidator 6. ValidationSummary The BaseValidator Class: The validation control classes inherit from the BaseValidator class and inherit its properties and methods. Therefore, it would help to take a look at the properties and the methods of this base class, which are common for all the validation controls: Members ControlToValidate Display Enabled ErrorMessage Text IsValid SetFocusOnError ValidationGroup Validate() Description Indicates the input control to validate. Indicates how the error message is shown. Enables or disables the validator. Error string. Error text to be shown if validation fails. Indicates whether the value of the control is valid. It indicates whether in case of an invalid control, the focus should switch to the related input control. The logical group of multiple validators, where this control belongs. This method revalidates the control and updates the IsValid property. 1. The RequiredFieldValidator:

2 The RequiredFieldValidator control ensures that the required field is not empty. It is generally tied to a text box to force input into the text box Example:-.REQUIRED FIELD VALIDATOR:- PROGRAM:-Name should not be blank SOURCE:- <asp:requiredfieldvalidator ID="RequiredFieldValidator1" runat="server" ControlToValidate="TextBox1" ErrorMessage="Sorry Cant let u go ahead with filling tha value..." ForeColor="Red" SetFocusOnError="True"></asp:RequiredFieldValidator> 2. The RangeValidator: The RangeValidator control verifies that the input value falls within a predetermined range. It has three specific properties: Properties Description Type MinimumValue MaximumValue it defines the type of the data; the available values are: Currency, Date, Double, Integer and String it specifies the minimum value of the range it specifies the maximum value of the range

3 3. The ValidationSummary Control The ValidationSummary control does not perform any validation but shows a summary of all errors in the page. The summary displays the values of the ErrorMessage property of all validation controls that failed validation. The following two mutually inclusive properties list out the error message: ShowSummary: shows the error messages in specified format. ShowMessageBox: shows the error messages in a separate window Example:-RANGE VALIDATOR AND SUMMARY VALIDATOR Program:-Enter your percentage expected in this semester and show the Summary of the above validation 4. The CompareValidator: The CustomValidator control allows writing application specific custom validation routines for both the client side and the server side validation. The client side validation is accomplished through the ClientValidationFunction property. The client side validation routine should be written in a scripting language, like JavaScript or VBScript, which the browser can understand.

4 The server side validation routine must be called from the control.s ServerValidate event handler. The server side validation routine should be written in any.net language, like C# or VB.Net. It has the following specific properties: Properties Type ControlToCompare ValueToCompare Operator it specifies the data type Description it specifies the value of the input control to compare with it specifies the constant value to compare with it specifies the comparison operator, the available values are: Equal, NotEqual, GreaterThan, GreaterThanEqual, LessThan, LessThanEqual and DataTypeCheck EXAMPLE:-COMPARE VALIDATOR. Program:- (a)comparing password. (b)age more than 18 SOURCE:- <asp:comparevalidator ID="CompareValidator1" runat="server" ErrorMessage="Please enter the same password" ControlToCompare="TextBox1" ControlToValidate="TextBox2" ForeColor="Red"></asp:CompareValidator> <asp:comparevalidator ID="CompareValidator2" runat="server" ControlToValidate="TextBox3" Display="Dynamic"

5 ErrorMessage="age should be greater than 18" ForeColor="#CC0000"Operator="GreaterThan" SetFocusOnError="True" Type="Integer" ValueToCompare="18"></asp:CompareValidator> 5. The RegularExpressionValidator The RegularExpressionValidator The RegularExpressionValidator allows validating the input text by matching or comparing the string to a pattern. These patterns are called as regular expression or regex. Pattern consist of literal characters and special characters, with no other special meaning. While special character has special meaning. The regular expression is set in the ValidationExpression property.

6 RegularExpressionValidator-special character use in a patterns Sign Meaning ^ The caret sign ^ specifies that checking starts from here $ The $ sign specifies that the checking ends here [] Square brackets [] checks that the value entered match with any of the characters that are in the square brackets. * * Sign is a qualifier that matches zero or more occurrences of the preceding character. {,} {,} indicates the Starting and ending numbers of a range of repetitions. + The + sign indicates that one or more elements to be added to the expression being checked RegularExpressionValidator-special character use in a patterns Sign Meaning.. Sign indicates,any single character.?? Sign is a qualifier that matches one or no occurrences of the preceding character. () () sign indicates group literal characters into a string that must be matched exactly. ( ) ( ) sign indicates a set of alternate string. \ \ sign indicates that the following character is a literal. - - sign represents all the character between two character.

7 RegularExpressionValidator-character class commonly used in pattern Class Short cut Meaning [0-9] \d Any digit. [\f\r\t\n\v] \s Any white space. [A-Za-z0-9] \w Any word character [^0-9] \D Not a digit. [^\f\r\t\n\v] \S Not white space. [^A-Za-z0-9] \W Not a word character Ex:- A five digit code pattern ^[0-9]{5}$ can be written as \d{5}$ 1. deptno(only digit)= "^[0-9]*$"

8 2. deptname(only char)= "^[A-Za-z]*$" 3. ename (chapital first letter and only char)="(^[a-z]{1})+.[a-z]" 4. eno(only two digits and alphanumeric)="(^[a-z]{1})?.([0-9]{1})$" 5. co.in org edu net)$" 6. mobile no="^([9]\d{9} [0]\d{10})$" 7. password (8 to 10 digits)="^([a-za-z0-9]{8,10})$" 8. Password (with special char)= ^[ 9. Password (without special char)= ^[0-9a-zA-Z]+$ VALIDATION ENDS