A virtual grid is a grid does not hold any data. All the data that are displayed by the grid is provided on demand from some external data source and sent to the grid when needed. Virtual grids are ideal for displaying large amounts of data. This data is not moved from its original location or stored in GridStyleInfo objects. Instead, GridStyleInfo objects are created on the fly to temporarily hold only the necessary data and are discarded when they are no longer needed. Hence, no data is stored in the grid.
Implementing a virtual grid is straightforward. Depending upon the functionality that you need, you can implement a virtual grid with as few as three events. To implement a virtual grid, you must tell the grid how many rows and columns your data source has and provide the grid with the data from your data source. You need to do these things in real time, only when the grid requests these data elements. When the grid needs to know the number of rows in it, it will fire the event QueryRowCount. When it needs to know the number of columns in the grid, it will fire the QueryColCount event. When it needs to know a GridStyleInfo object for a particular cell, it will fire the QueryCellInfo event. By handling these events and setting appropriate members of the EventArgs, you can provide the information that the grid needs at the time it needs it.
Here is a list of the different samples under this category:
Getting Started This sample illustrates the binding of a grid to an external data source so that no data actually resides in the grid.
Virtual Grid Demo- This sample illustrates the binding of a grid to an external data source so that the data actually resides in the grid.
Virtual Tree Grid Demo- This sample displays an ordered, flat data source as a tree.
Grid Population Demo - This sample illustrates different ways of Essential Grid population.