The 'update' property

Boolean Scalar

Valid for: Chart, Picture

Normally, when you change a property or invoke a method which has a visual effect, the screen is immediately updated to reflect the change. For example, if you change the title of a Chart, it is immediately redrawn. Sometimes, however, you may wish to suppress re-drawing temporarily - for example, if you are making lots of changes to a Chart, or to an Image object which is displayed in a Picture, and you do not want to redraw it until all the changes have been made. The update property can be used to suppress and enable redraws.

The default value for update is 1, meaning that updates take place immediately (when events are next handled). If you set it to 0, no drawing or re-drawing will take place. When you set it to 1 again, the whole control will be redrawn, and from then on updates will be processed as normal.

Changing the update property should be done with care, since if you set it to 0 and do not set it back to 1, the control will not respond to update events and will not display correctly.