TStringList.BeginUpdate
procedure BeginUpdate()
Description
BeginUpdate increases the update count by one. It is advisable to call BeginUpdate before lengthy operations on the stringlist. At the end of these operation, EndUpdate should be called to mark the end of the operation. This information might be used to perform optmizations. e.g. updating the screen only once after many strings were added to the list.
Always put the corresponding call to EndUpdate in the context of a Finally block, to ensure that the update count is always descreased at the end of the operation, even if an exception occurred.
Example
...
With MyStrings do
try
BeginUpdate;
// Some lengthy operation.
Finally
EndUpdate
end;
...