Note: This topic applies to both the Web Forms Application presentation project types and Web Forms Mobile Application presentation project types. Refer to Creating Web Forms Application Projects and Creating Web Forms Mobile Application Projects.
This example shows how you can use ePortal runtime validation of message fields, combined with the Microsoft CustomValidator control to perform advanced validation for your web forms or mobile application.
Consult the following topics for background information before reviewing this example:
The topic "CustomValidator control" in the MSDN online help.
You can use the Microsoft ASP.Net CustomValidator control to perform your own custom validation on a web page. When combined with ePortal runtime error checking for message fields, you can perform advanced validation such as the following:
Verify that single-byte characters are not inadvertently entered into a web form field that is intended for double-byte characters only.
Verify that a value entered into a web form field will not overflow the size allocated for the data on the server system.
These scenarios apply to web forms which can accept Asian characters.
Sample ePortal messages
For this example, consider the case where the following COBOL 01 record is imported:
OS 2200 example
01 IN-RECORD. 05 STRING-5-CHAR PIC X(5) USAGE DISPLAY. 05 STRING-5-DOUBLE-CHAR PIC X(5) USAGE DISPLAY-2.
MCP example
01 IN-RECORD. 05 STRING-5-CHAR PIC X(5) USAGE DISPLAY. 05 STRING-5-DOUBLE-CHAR PIC X(5) USAGE NATIONAL.
In this case, ePortal creates a server message and a client message named IN_RECORD. The message validation field properties are configured as follows:
| Field Name | Required | Pattern | MaxBytes | DoubleByteCharsOnly |
|---|---|---|---|---|
| STRING_5_CHAR | False | Empty | 5 | False |
| STRING_5_DOUBLE_CHAR | False | Empty | 10 | True |
Sample ePortal Web Page
If you add a web presentation, ePortal generates a web page file, named IN_RECORD.aspx, with one TextBox for STRING_5_CHAR and another TextBox for STRING_5_DOUBLE_CHAR. ePortal also generates the code-behind file, named IN_RECORD.aspx.cs.
Code in the code-behind file automatically validates that:
The application cannot enter a value into the field STRING_5_CHAR that exceeds 5 bytes when it is encoded into the application character set.
The application user cannot enter single-byte characters into the field STRING_5_DOUBLE_CHAR. The user can only enter double-byte characters, such as Kanji.
If an error is detected, a pop-up message box appears.
The application developer may prefer some other action to occur in the event of an error. For example, the developer may want to display an asterisk next to the field in error, and display a summary of detailed messages at the bottom of the page. The application developer can accomplish this by using the CustomValidator control.
Performing Custom Validation for Input Overflow
To perform custom validation looking for possible input overflow for the field STRING_5_CHAR, do the following:
Drag a CustomValidator control onto the web page after the TextBox for STRING_5_CHAR. Refer to Adding Validation to Your Web Forms Page for details.
In the Properties window, click the Events toolbar button to switch to the Events view.
Double-click the ServerValidate event. This opens the code-behind file and adds an empty event handler method.
Add code, similar to the following example, to perform the server-side validation:
protected void String5Validator_ServerValidate(object source, ServerValidateEventArgs args)
{
BaseValidator validator = source as BaseValidator;
try
{
IN_RECORD_obj.STRING_5_CHAR = args.Value;
args.IsValid = true;
}
catch (Unisys.Common.Runtime.ProcessOrch.InputDataOverflowException idoe)
{
args.IsValid = false;
if (validator != null)
{
validator.ErrorMessage = idoe.WebMessage;
}
}
}
Notes:
Assigning args.Value to IN_RECORD_obj.STRING_5_CHAR throws an InputDataOverflowException if the value that the user entered would cause an overflow. Refer to Orchestration Exception Properties.
The code sets args.IsValid to true if validation passes, or false if validation fails.
The code sets the property ErrorMessage for the CustomValidator control to the error message to be displayed. In the example code, the error message is copied from the caught exception. Alternatively, the application developer might choose to customize this error message, possibly by accessing other fields in the caught exception. Refer to Orchestration Exception Properties.
Performing Custom Validation for Single-byte Characters
To perform custom validation looking for unexpected single-byte characters in field STRING_5_DOUBLE_CHAR, do the following:
Drag a CustomValidator control onto the web page after the TextBox for STRING_5_DOUBLE_CHAR. Refer to Adding Validation to Your Web Forms Page for details.
In the Properties window, click the Events toolbar button to switch to the Events view.
Double-click the ServerValidate event. This opens the code-behind file and adds an empty event handler method.
Add code, similar to the following example, to perform the server-side validation:
{
BaseValidator validator = source as BaseValidator;
try
{
IN_RECORD_obj.STRING_5_DOUBLE_CHAR = args.Value;
args.IsValid = true;
}
catch (Unisys.Common.Runtime.ProcessOrch.InvalidCastException ice)
{
args.IsValid = false;
if (validator != null)
{
validator.ErrorMessage = ice.WebMessage;
}
}
}
Notes:
Assigning args.Value to IN_RECORD_obj.STRING_5_DOUBLE_CHAR throws an InvalidCastException if the value that the user entered contains single-byte characters. Refer to Orchestration Exception Properties.
The code sets args.IsValid to true if validation passes, or false if validation fails.
The code sets the property ErrorMessage for the CustomValidator control to the error message to be displayed. In the example code, the error message is copied from the caught exception. Alternatively, the application developer might choose to customize this error message, possibly by accessing other fields in the caught exception. Refer to Orchestration Exception Properties.