Move Grid Rows

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Here's some demo code showing how to move a row up or down the grid based on arrow clicks.

Moving the row requires a temporary TStringlist to hold a row while it is being replaced. There are two versions of the MoveGridRow procedure, one receiving a pre-allocated Temp string list as part of the calling parameters, another which allocates the string list, moves the rows, and then frees the list. The timing buttons compare times for the two methods and seem to indicate that pre-allocating has very little (or negative) speed-up effect. The 2nd timing button hides the grid while moving and shows that redrawing the grid uses much more time than actual row move time.

A viewer had requested the ability to carry a hidden "record number" along with each row. I implemented this using the "Objects" property for cell 0 of each row to hold an integer. Test numbers were generated as 10x the original row number. To verify that object data was moved with the rows, Gordon's button lists the record numbers after the rows have been rearranged.
 

Download source code 

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Created: August 23, 2010

Modified: May 12, 2018

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