DataBoundGrid ColumnMapping Question

[Administrator]

I have a grid bound to a sql dataset with about 20 columns in. I have used the designer to bind the column names in the dataset to the grid columns I have set up. I would like my users to be able to show or hide columns based on checkbox option controls. i.e If they check the "Stock Info" checkbox then I would un-hide the 4 columns with stock information in.

I have made a Sub that shows or hides a columns based on its gridcolumn index but I would ideally like to show or hide a columns based on its dataset mapping name so that if I change the order of my grid columns at a later date I dont have to re-index all these show hide functions.

Ideally I would like it to work like this:

Me.Grid.Model.HideCols(Me.Grid.Binder.MappingToColIndex("qtyinstock")) = False

Then I would just repeat this for each column I would want to hide.

Can you point me in the right direction?

[Administrator]

In a GridDataBoundGrid, you can index the grid.Model.Cols.Hidden collection with a mappingname. So, code like this should hide a column whose ColumnName is "Col1".

Me.gridDataBoundGrid1.Model.Cols.Hidden("Col1") = True

[Administrator]

That worked like a treat thanks v much.

However when the hidden columns are shown they take over a second to appear and you can almost see them drawing as they appear. Is there a way to un-hide mutiple columns at the same time or a better way to refresh the grid? It seems quirky that I have a loop through the columns that I want to un-hide or can I specify a list or collection to the HideCols function?

I woud rather that I re-draw all the columns at once rather than have to do three re-draws when I unhide three columns. The grid is faily dense but I am only using static cells and simple alternating row colours and some cell borders.

[Administrator]

Try calling

grid.BeginUpdate()
''show multiple columns
''
''
grid.EndUpdate()
grid.Refresh()

This should turn off drawing until all the columns are marked visible, and then draw them all at once.

[Administrator]

Thanks for the tip, that made the redraw of the hidden columns a lot quicker.

Now I have a problem with cell background colours which I am colouring using PrepareViewStyleInfo. I am alternating the row colurs which I have done and I am also re-colouring the row on certain conditions and now I need to add in about 10 more conditions for colouring the backgorund of the cell. I can use the column index to do this but I have the same problem as with the hidden columns that if I change the ordering of the columns I am going to have to re-do all my code again.

Using this code causes the grid drawing to slow right down

If Me.grd_Data(e.RowIndex, Me.grd_Data.Binder.InternalColumns("deleted")).Text = "Y" Then
e.Style.BackColor = ColorTranslator.FromHtml("#ffe0e0")
ElseIf Int(Me.grd_Data(e.RowIndex, Me.grd_Data.Binder.InternalColumns("stockqty")).Text) > 0 Then
e.Style.BackColor = ColorTranslator.FromHtml("#ccffcc")
End If

So I thought I would create a hastable or array that holds the gridmapping name (for ease of use) and the grid column index (for quicker access to grid features). Could you provide me with a sample of how to loop though the columns of the grid pull out the index and mapping name?
Then using the array I can get the PrepareViewStyleInfo to execute quicker rather than going to the underlying binder all the time or am I totally doing this wrong?

Thanks, Mark

[Administrator]

>Me.grd_Data.Binder.InternalColumns("deleted")).

If this is the code you are using to produce a column location in PrepareViewStyleInfo, I suspect you may be getting some exceptions being thrown, and that will slow things down.

Instead of the above, try

Me.grd_Data.Binder.NameToColIndex("deleted") 

to retrive the ColIndex for the column named "deleted".