Re: Deep databinding - constructing datagrid on the fly

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From: Duncan M Gunn (gunnd_at_gaelqualityNOSPAM.co.uk)
Date: 01/26/05

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    Date: Wed, 26 Jan 2005 14:12:05 -0000

    We managed to solve this problem.

    The answer lies with PropertyDescriptor objects. Using the example given in
    the previous post, ListOfRowObjects should implement IBindingList,
    ITypedList. In GetItemProperties(), create a CellPropertyDescriptor object
    for each of the columns represented by the list of ColObjects, initialising
    the ColumnIndex property of each.

    When the datagrid requests data from the ListofRowObjects, it will iterate
    over each PropertyDescriptor first, for each RowObject in its list.
    CellPropertyDescriptor.GetValue() is called, which is passed the current
    RowObject. RowObject.GetValue() can then be called by
    CellPropertyDescriptor, and if it is passed the ColumnIndex property then we
    have the (x,y) co-ordinate of the cell being rendered in the grid.
    RowObject (or ListOfRowObjects could be delegated this responsibility) can
    then work out the value which should be returned.

    Hope this is of use to someone.

    Now I have to find a way of efficiently storing the Cells. I can't just
    create a list of Cell objects for each (x,y) position in the grid, as there
    will be several empty Cell objects - the ListOfRowObjects can return a
    default value when it is asked for a Cell which is empty for a given (x,y)
    value - there is no need to actually store an empty Cell object.

    Does anyone know of an efficient storage mechanism for a matrix structure
    such as this?

    Thanks,
    Duncan

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