DELPHI control development is in-depth and simple
Someone has said that "Delphi programmers who cannot develop controls are not real programmers." It is precisely because of its high scalability and support for a large number of third-party controls that Delphi can attract the critical eyes of countless programmers. Even developers who need to use other development tools for their work often miss the days and nights spent with Delphi. It has been more than a year since I came into contact with Delphi. I was overwhelmed by the hundreds of controls on the Delphi component panel, and now I can develop some difficult controls according to my needs. The road I have traveled has been very difficult, so hereby Writing this article and leaving my experience to those who come after me can be regarded as a generous gift to my “fellow juniors”!
One thing that needs to be explained is: before writing this article, I assume that the reader already has a certain understanding of the basic knowledge of object-oriented, so I will not elaborate on the concepts related to object-oriented in the article.
1. Trial test - TURLLabel control
Let's start our control development journey with a label control that can add hyperlinks!
Since it is Label, let us derive this control from Tlabel (actually it is best to derive it from TcustomLabel, but for simplicity purposes we will derive it from Tlabel here)!
1. Select "File"->"New"->"Component", the following dialog box will pop up:
Select Tlabel in Ancestor type, fill in TURLLabel in ClassName (the name can be any Take, but it must start with T, otherwise there will be problems when registering the control). Here Ancestor type represents the base class of the control, and TURLLabel represents the name of the control.
2. The visual effect of the hyperlink is underlined text, so we override the constructor of the parent class and modify the font attribute of the control in the constructor.