Aus der Hilfe:
Zitat:
function ExtractFileExt(const FileName: string): string;
Description
Use ExtractFileExt to obtain the extension from a file name. For example, the following code returns the extension of the file name specified by a variable named MyFileName:
MyFilesExtension := ExtractFileExt(MyFileName);
The resulting string includes the period character that separates the name and extension parts. This string is empty if the given file name has no extension.