If necessary, you can edit the Web Forms code-behind file to provide finer control over the operation of your Web page at runtime.
Methods in the Code-Behind File
When you build your presentation project, ePortal generates the code-behind file containing the following methods. Unless otherwise noted, you can modify the code in these methods or add additional code. However, you should not modify the existing code that ePortal generated unless you have an advanced understanding of ASP.Net programming.
Note: Unisys recommends that you modify only the methods SetFields and PostFields.
Page_Load
The method Page_Load executes when the Web page first loads (for example, on an HTTP get request for the page), or whenever the page posts back to the Web server (for example, when the user submits the page).
The generated code does the following:
Initializes an object representing the ePortal Client Message.
For the get request only:
Calls method ePortalSetFields
Calls method SetFields
ePortalSetFields
The ePortalSetFields method copies data from the ePortal Client Message to the controls on the Web page.
Note: This method is regenerated on every build of the presentation project, so you should not modify this method. Any changes you attempt to make to this method will be lost when you build the project.
SetFields
The method SetFields is empty when initially generated by ePortal. You can add your own custom code to run when the Web page is first loaded, after a get request. For example, you might want to add code here to initialize the value of a Web control, based on conditions known only at runtime, such as the time of day.
ePortalSubmit
The method ePortalSubmit is an event handler method used to submit the Web page. For a generated Web Forms presentation application, the user clicks the Submit button to invoke the ePortalSubmit method. For a generated mobile presentation application, the user taps the Send button to invoke the ePortalSubmit method.
The generated code does the following:
Sets the local boolean variable validate to true if the submit button CausesValidation property is true. By default, CausesValidation is true for an ePortal submit button.
Calls method ePortalPostFields, passing validate as a parameter.
If ePortalPostFields returns true:
Calls method PostFields.
If PostFields returns true:
Submits the Web page to the ePortal runtime.
If the Web page is not submitted to the ePortal runtime, the user remains on the same page. This occurs if validation detects a problem and displays an error message.
ePortalPostFields
The ePortalPostFields method accepts a boolean parameter named validate. If the validate parameter is true, ePortalPostFields performs validation for any ASP.Net Validation Controls (refer to the topic Adding Validation to Your Web Forms Page).
If validation for ASP.Net Validation Controls succeeds, ePortalPostFields copies data from the controls on the Web page to the ePortal client message. If the client message is configured to perform runtime error checking, validation is performed as each field in the client message is set. Refer to Runtime Error Checking for Message Fields.
This method returns true if all validation passes. Otherwise, this method returns false.
Note: This method is regenerated on every build of the presentation project, so you should not modify this method. Any changes you attempt to make to this method will be lost when you build the project.
PostFields
The PostFields method returns true when initially generated by ePortal. You can add your own custom code to run when the Web page is submitted. For example, you might want to perform additional complex validation of user input.
If this method returns false, no data is submitted to the ePortal runtime, and the same Web page is displayed.
ePortalClose
ePortalClose is an event handler method, intended to close the session between the application and ClearPath server. For a generated Web Forms presentation application, the user typically clicks the Close button to invoke the ePortalClose method. For a generated mobile presentation application, there is no button included to perform this operation by default. However, the developer can explicitly add a button to the page and set the Click event handler action to ePortalClose to cause this method to be called. The generated code does the following:
Disconnects the connection between the Web server and the ClearPath server.
Displays the Closed.aspx page.
ePortal Objects and Classes
Additional classes and objects are made available to the code-behind file by ePortal. The data source project is represented by an object derived from Unisys.Component. Each Web page has an object associated with it, derived from Unisys.Message. This object takes the name of the page, suffixed by _obj. For example, the logon page has the object logon_obj.
Additionally, the Unisys.WebSupport class provides static methods used by the ePortal framework to perform functions such as initializing and ending sessions, initializing each page, and sending and receiving data from the ClearPath Server.
Unisys.Component
For each data source project, a class derived from Unisys.Component, is created and used by the framework to connect to the ClearPath Server, disconnect from the ClearPath Server, and to send and receive data to and from the ClearPath Server.
This class is not intended to be accessed by user-written code.
Unisys.Message
For each page, ePortal creates a class derived from Unisys.Message. The ePortal framework makes this class available for use by both ePortal code and user-written code in the code-behind file. In the code-behind file, this class is referenced by the variable pageName_obj.
This class is used to transfer data between the ClearPath Server and the .aspx page Web form controls. The class contains accessors for each field in the Client Message. To get or set the value of a field in the Client message, the construct pageName_obj.fieldName is used.
For example, to get a value from a field in a client message, use an assignment such as:
String uc = logon_obj.usercode;
To set a value in a field in a client message, use an assignment statement such as:
logon_obj.usercode = "myusercode";
If a field in a client message is not of Type string, an additional accessor converts the value to the correct type as the field is set. This accessor has a name of the form _convert_to<fieldname>.
For example, if the client message logon contains an integer field named accountNumber, use an assignment such as:
logon_obj._convert_to_accountNumber = accountNumberTextBox.Text;
If runtime error checking is enabled, the accessors contain code to perform the validation when a field is set to a new value. This means that an exception could be thrown when setting a value. Refer to Runtime Error Checking for Message Fields.
The class also contains an accessor for another member variable for each field called <fieldname>Field. This additional field is of type Unisys.Common.EISConnectors.EISField. This field contains additional information about the field.
This field is not intended to be accessed by user-written code.
Unisys.WebSupport
The Unisys.WebSupport class provides static methods used by the ePortal framework to perform function such as, initializing and ending sessions, initializing each page, and sending and receiving data to/from the ClearPath Server. Methods used in the code-behind file are described below.
InitializePage
This method checks that the correct page is being requested (current page) and that the correct security (HTTP or HTTPS) is being used. If not, the browser is redirected to the correct page with the correct security and the method does not return. If the previous checks pass, the method returns the pageName_obj object derived from Unisys.Message, which is stored in a class instance variable.
Submit
This method takes the data in the pageName_obj object and sends it to the ClearPath Server. The method waits for a response from the ClearPath Server. Control is transferred to the .aspx page corresponding to the page received from the ClearPath Server. This appears as an HTTP get request to the transferred .aspx page.
This method never returns to the calling page.
Refresh
This method transfers control to the current page. To the .aspx page this appears as a new HTTP get request. This method never returns to the calling page. This may be useful if the ClearPath Server has sent data after a page is displayed on the client browser.
SetStyles
Note: This method applies to MCP T27 and OS 2200 UTS applications only.
This method is used to set the Style and/or Class (for example, cssclass) attributes of controls whose style may change when the application is running. For example, an input field's highlight may be set to "bright" by the ClearPath Server application if a required field is left blank.
This method takes two parameters, System.Web.UI.Control ctrl and String cls. The method uses the StyleMap as indexed by cls.
Unisys.WebSupport.SetStyles(Usercode, logon_obj.UsercodeField.@class);
SetAssociateFields
This method is used to initialize Associated Controls on the .aspx page with the same value as its corresponding control.
This method is not intended to be called by user-written code.
Logging and Tracing
Your code can also write messages to the ePortal log for debug or auditing purposes; refer to Logging Messages from your Code and Logging Errors and Tracing for more information.
JavaScript
If you incorporate external JavaScript in your pages, you must register the file containing the JavaScript. To register the file userscript.js, add the following line to the Page_Load method:
ClientScript.RegisterClientScriptInclude
("MyScript1","../Scripts/userscript.js");