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 window is not valid or when the application closes. CancelHint calls a series of routines that clean up the display and timing…
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…
We use TextRect to write a string inside a clipping rectangle or within a limited rectangular region. Any portions of the string that fall outside the rectangle passed in the Rect parameter are clipped and don’t appear. The upper left corner of the text is placed at the point (X, Y).
Here is the working example of the implementation of an OnClose event like in the Section 7 (Getting…
OnClose event occurs when the form closes.
We use OnClose to perform special processing when the form closes. The OnClose event specifies which event handler to call when a form is about to close. The handler specified by OnClose might, for example, test to make sure…
OnSelectCell event occurs before a cell in the grid is selected.
Write an OnSelectCell event handler to specify whether any particular cell in the grid can be selected. The Col and Row parameters indicate the column and row indexes of the cell that is about to be…
OnDrawCell event Occurs when a cell in the grid needs to be drawn.
We write an OnDrawCell event handler to draw the contents of all the cells in the grid. Draw on the cell using the methods of the Canvas property. The Rect parameter indicates the location of the cell on the canvas. The Col and Row parameters indicate the column and row indexes of the cell that should be drawn. The State…
OnChange event occurs when the user changes the text displayed in the edit region.
We write an OnChange event handler to take specific action immediately after the user edits the text in the edit region or selects an item from the list. The Text property gives the new…
OnClick event occurs when the user clicks the control.
We use the OnClick event handler to respond when the user clicks the control. If the control has an associated action, and that action has an OnExecute method, the action’s OnExecute method responds to click…
BiDiMode property or DelphiVCL.Application.BiDiMode is used to indicate the layout of the application when running under Middle Eastern versions of Windows.
Use BiDiMode to specify the bi-directional mode for the application. The bi-directional mode controls the direction in which text appears (left-to-right or right-to-left), the placement of vertical scroll bars, and the default alignment…
