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Components of Px Framework: Validation, checking of the entered values by means of the PxWebQuery component and other visual components (PxEdit, PxComboBox, etc.)Through the PxEdit component (as well as PxComboBox, PxFlyComboBox, PxJSDatePicker, etc.) the PxWebQuery component contains and automatic validation. If the table column linked to the PxEdit component is of the string type, validation of the string length is automatically carried out, if it is of the int type, validation operation to check whether the integer has been entered is carried out, in case of the date type, validation operation to check whether the valid date has been entered is carried out, etc. The picture below shows an example where we have entered a string which length exceeded the length of string defined in the database. Then we have entered an invalid date. Linking the PxWebQuery and the PxEdit component causes the automatic validation. If the value specified in the PxEdit component does not correspond to the given type, it shall not pass the automatic validation, data storing shall be automatically stopped, and the PxEdit component shall report an error message stating the reason for which the data has not been stored.  In addition to the automatic validation, there are additional validations, defined in the PxWebQuery component via the AddParamValidation parameter.
wquAdresar.AddParamValidation("name", "vtIsNotNull");
In this case, data storing shall not be carried out if the "Name" column is not filled out, and after pressing the "Ok" button the original form shall remain and the "Persons Name" component shall report the error message. Please refer to the picture below:  Similarly, if the "vtIsNotNull" validation parameter is applied to the "juridical form" column, the original form shall remain after pressing the "Ok" button until any value from the "juridical form" list is selected. The command specifying the juridical form validation parameter shall be as follows:
wquAdresar.AddParamValidation("idpravnaforma", "vtIsNotNull");
If no Juridical Form from the combobox is selected, the original form shall remain after the "Ok" button is pressed, and the reason why the form has not been saved shall be stated in red letters. Please refer to the picture below.  Definition of the AddParamValidation command:
public void AddParamValidation(string sFieldName, string sEnumValidationTest,
Description of the parameters of the AddParamValidation command: sFieldName - field name , column name, to which this validation type shall be applied sEnumValidationTest - validation type, control type that shall be carried out, description of individual fields shall be given below sRegularExpression - expression for setting the validation via regular expressions iMinMaxValue - minimal, maximal expression value at the specified integer field type sErrorMsg - this expression serves for re-writing or entering of a new error message at this validation type Description of individual validation types:
Each type of validation has the fixed error message assigned to it. If you want to change this error message in case its text is not satisfactory, you can do it in the following way:
wquAdresar.AddParamValidation("name", "vtIsNotNull", "", 0, "You did not name the person!!!");
Further, there is an example of validation using regular expressions. This book is not intended to describe how to operate with regular expressions and how to compile them, for further information please refer to various web resources. We have added another column to the "adresar" table. This column serves for entering the zip code. Define validation via the regular expression to the Adresar.aspx.cs file as shown below:
string sRegVyrazToPSC = @"^\d{5}$|^\d{3}\s\d{2}$";
The defined regular expression allows to enter a 5 digit number, either with a space after the third digit, with or without a gap. Whenever you want to carry out validation via the regular expression, you have to specify the "vtValidToRegularExpresion" validation type. If validation for the zip code item is defined in such a way, entering of an incorrect zip code shall stop saving of a form. The error message defined in the "ERRORMSG" expression shall appear after the zip code component, please refer to the picture below.  During the automatic validation and control of the length string, validation may not work quite right. It depends on the code page that is set in the database. If you use the database code page with UTF8 the characters with diacritics in the Oracle database occupy the 2 characters and some special characters to 3 characters in the database. Therefore, you must set the property of the CharacterCode component in PxWebQuery to "UTF8" so that the validation of the string length work properly. In the following we list costants of the CharacterCode property for the proper functionality of validation of the string length. The CharacterCode property is default set to ASCII.
If we set the code page to UTF8 in the database we should set it to the CharacterCode property before opening the PxWebQuery component. See examples below:
wquAdresar.CharacterCode = "UTF8";
Here is a functional example of the PxWebQuery component, even with source code. This functional example on this site runs on MySQL 5.0 database.
Others articles of Px Framework:
It doesn't the intention of this part website, describe in detail the work with PxFramework components, a detailed description of the component available in manual, which can be downloaded here: Download manual of Px Framework |