CIniFile: Difference between revisions
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An object of the cIniFile class can be used for reading information avaiable from an INI file. | An object of the '''cIniFile''' class can be used for reading information avaiable from an INI file. | ||
INI files are often used to store user preferences or setup options for applications. | INI files are often used to store user preferences or setup options for applications. | ||
==INI files== | |||
In [[Visual DataFlex]] you can freely use as many INI files as you require, however the two-level structure of INI files (sections and keys) means that there is often no need to use more than one. Here, for example, is a boot.ini file (usually found in the root directory of the system drive of Windows operating systems): | In [[Visual DataFlex]] you can freely use as many INI files as you require, however the two-level structure of INI files (sections and keys) means that there is often no need to use more than one. Here, for example, is a boot.ini file (usually found in the root directory of the system drive of Windows operating systems): | ||
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As you can see, it defines two sections - [boot loader] and [operating systems] - each with different settings within them. | As you can see, it defines two sections - [boot loader] and [operating systems] - each with different settings within them. | ||
==Visual DataFlex Workspace files== | |||
Another example are the workspace configuration files used by [[Visual DataFlex]] itself (by default named "Config.ws", showing that they don't have to use the .ini extension - see the artice in "See Also" below), which must exist in the same directory the program is run from (usually the "Programs" subdirectory of the workspace). Here is an example: | Another example are the workspace configuration files used by [[Visual DataFlex]] itself (by default named "Config.ws", showing that they don't have to use the .ini extension - see the artice in "See Also" below), which must exist in the same directory the program is run from (usually the "Programs" subdirectory of the workspace). Here is an example: | ||
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Note that section names (the ones in the square brackets), key names ("Home", "AppSrcPath", etc.) and key values can all contain spaces (although for my own part I prefer not to use those and depend on [http://en.wikipedia.org/wiki/Camelcase camelCase] to supply readability). | Note that section names (the ones in the square brackets), key names ("Home", "AppSrcPath", etc.) and key values can all contain spaces (although for my own part I prefer not to use those and depend on [http://en.wikipedia.org/wiki/Camelcase camelCase] to supply readability). | ||
==INI file advantages== | |||
The advantage of the INI file approach is that it can make programs configurable for different environments or uses without them having to be recompiled with different settings each time: the program can be made with a set of default values which can then be overridden at run-time by the settings in an INI file. It has the advantage over Registry settings, which perform very much the same function, in that you don't need any special rights on the machine to set it up and make changes to it: you are just working with text files, so security policy issues about who has rights to the [http://en.wikipedia.org/wiki/Windows_Registry Windows Registry], or who can run RegEdit or RegEdit32 do not apply - if you can run Notepad and modify files you can configure your application. | The advantage of the INI file approach is that it can make programs configurable for different environments or uses without them having to be recompiled with different settings each time: the program can be made with a set of default values which can then be overridden at run-time by the settings in an INI file. It has the advantage over Registry settings, which perform very much the same function, in that you don't need any special rights on the machine to set it up and make changes to it: you are just working with text files, so security policy issues about who has rights to the [http://en.wikipedia.org/wiki/Windows_Registry Windows Registry], or who can run RegEdit or RegEdit32 do not apply - if you can run Notepad and modify files you can configure your application. | ||
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Combining these factors - the fact that there is probably no need to have more than one INI file, and the fact that [[Visual DataFlex]] requres one anyway - means that for most purposes you can just add what you need to the existing workspace configuration file. | Combining these factors - the fact that there is probably no need to have more than one INI file, and the fact that [[Visual DataFlex]] requres one anyway - means that for most purposes you can just add what you need to the existing workspace configuration file. | ||
==Accessing INI files== | |||
So how do you access that information in your program? | So how do you access that information in your program? | ||
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But some might consider that a bridge too far! | But some might consider that a bridge too far! | ||
==Summary== | |||
The cIniFile has other methods as well: it can write as well as read (WriteString, DeleteKey and DeleteSection) and can dynamically determine the contents of the file (ReadSections, ReadSection, SectionExists and KeyExists) - see the VDF Help for full information - but the ReadString method is the one you will need in most circumstances. | The cIniFile has other methods as well: it can write as well as read (WriteString, DeleteKey and DeleteSection) and can dynamically determine the contents of the file (ReadSections, ReadSection, SectionExists and KeyExists) - see the VDF Help for full information - but the ReadString method is the one you will need in most circumstances. | ||