The ControlDestroyed method or DelphiVCL.Application.ControlDestroyed is used to notify the application when a control is destroyed.
ControlDestroyed is for internal use and is called automatically by TControl. Do not call it directly.
ControlDestroyed notifies the application that the control passed as the Control parameter has been destroyed, so that the properties which refer to…
The ComponentCount property or DelphiVCL.Application.ComponentCount is used to indicate the number of components owned by the component.
Use the ComponentCount property to determine the number of components owned by a component, for example, when iterating through the…
The ComObject property or DelphiVCL.Application.ComObject is used to specify the interface reference implemented by the component.
Use ComObject to assign a COM interface implemented by a component to an interface reference. This property is used by components that…
Text property contains a text string associated with the control.
We use the Text property to read the Text of the control or to specify a new string for the Text value. By default, Text is the control name. For edit controls and memos, the Text appears within the control. For combo boxes, the Text is the content of the edit control portion of the combo box.
Note: Controls that…
The ClassType method or DelphiVCL.Application.ClassType is used to return the class reference for the object’s class.
Note: ClassType dynamically determines the type of an object and returns its class reference, or metaclass.
Avoid using ClassType in…
The ClassName method or DelphiVCL.Application.ClassName is used to return a string indicating the type of the object instance (as opposed to the type of the variable passed as an argument).
Use ClassName to obtain the class name from an object instance or class…
The ClassInfo method or DelphiVCL.Application.ClassInfo is used to return a pointer to the run-time type information (RTTI) table for the object type.
ClassInfo provides access to the RTTI table for a given object type.
Some classes do not provide run-time type information. For these classes, ClassInfo returns nil (Delphi) or NULL (C++). All classes descended from TPersistent do…
The CancelHint method or DelphiVCL.Application.CancelHint is used to cancel the display of a hint for a control.
Applications rarely, if ever, call CancelHint directly. CancelHint is used internally to cancel the display of hints at appropriate times, such as when a…
We use Caption to specify a text string that identifies the control to the user.
To underline a character in a Caption that labels a component, include an ampersand (&) before the character. This type of character is called an accelerator character. The user can…
We use the Parent property to get or set the parent of the control. The parent of a control is the control that contains it. For example, if an application includes three radio buttons in a group box, the group box is the parent of the three radio buttons, and the radio buttons are the child controls of the group box.
To serve as a parent, a control must be an instance of a TWinControl…
