With our method just added, the next step is to type in the associated Code Editor the code that will be executed when we call it. Getting a Quick Look Icon… and a Regular one In our method definition we are setting the QuickLookIcon parameter to the default Boolean value True.
In addition, we can also provide a default value for our Optional parameter that is the value that will receive the method if we don’t provide a value of our own. In fact, in the previous code snippets you might have noticed the last parameter was omitted in the method call. We include that keyword in the method signature to indicate that such parameter is… well… optional that is, you can provide the parameter in the method call or not. The second thing you’ll probably find of interest in the method definition is the use of the Optional keyword. Notice as the second chunk of code is calling the method using the dot notation on the FolderItem instance referenced by the f variable and how, in that case, we don’t need to provide the FolderItem variable as one of the parameters in the method call. Var p As Picture = f.IconForFile(tSize) // IconForFile as an extended method for the FolderItem class We are able to call the method this way: Var f As FolderItem = FolderItem.ShowOpenFileDialog("") Var p As Picture = IconForFile(f, tSize) // IconForFile as a regular method definition So, instead of using the following syntax: Var f As FolderItem = FolderItem.ShowOpenFileDialog("") The main convenience of extended class methods is that your code will be more readable and you’ll be able to call the method on a data type instance using the dot notation. In brief, that means that the method will be treated as a method for the data type (or class) included next to the defined parameter in this case the FolderItem. If you are new to coding in Xojo, then probably you’ll be wondering what “ Extends” means in the signature method. Parameters: Extends f As FolderItem, tSize As Size, Optional QuickLookIcon As Boolean = True.We will start by adding a new method to a Module in a Xojo Desktop project using the following method signature:
#Xojo folderitem download
You can download the Xojo Project file from this link. Once we have “declared” these kind of functions from Xojo code, they will be ready to be used when calling any of your own defined methods or any of the methods directly available from the Xojo classes.
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