Better way to display [error] messages

If you display more than a few [error] messages in your application, using a simple method such as the following may not be the best approach:

Application.MessageBox( 'File not found', 'Error', mb_OK );

Above method of displaying errors will make it harder to modify actual messages since they are distributed all over your application source code. It may be better to have a "centralized" function that can display error messages, or better yet, a centralized function that can display replaceable error messages. Consider the following example:

type cnMessageIDs = ( nMsgID_NoError, nMsgID_FileNotFound, nMsgID_OutOfMemory, nMsgID_ExitProgram // list your other error // IDs here... ); const csMessages_ShortVersion : array [ Low( cnMessageIDs ).. High( cnMessageIDs ) ] of PChar = ( 'No error', 'File not found', 'Out of memory', 'Exit program?' // other error messages... ); csMessages_DetailedVersion : array [ Low( cnMessageIDs ).. High( cnMessageIDs ) ] of PChar = ( 'No error; please ignore!', 'File c:\config.sys not found.'+ 'Contact your sys. admin.', 'Out of memory. You need '+ 'at least 4M for this function', 'Exit program? '+ 'Save your data first!' // other error messages... ); procedure MsgDisplay( cnMessageID : cnMessageIDs ); begin // set this to False to display // short version of the messages if( True )then Application.MessageBox( csMessages_DetailedVersion[ cnMessageID ], 'Error', mb_OK ) else Application.MessageBox( csMessages_ShortVersion[ cnMessageID ], 'Error', mb_OK ); end;

Now, whenever you want to display an error message, you can call the MsgDisplay() function with the message ID rather than typing the message itself:

MsgDisplay( nMsgID_FileNotFound );

MsgDisplay() function will not only let you keep all your error messages in one place -- inside one unit for example, but it will also let you keep different sets of error messages -- novice/expert, debug/release, and even different sets for different languages.