Drawing Cell Borders Selectively | Infragistics Forums

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Drawing Cell Borders Selectively

Howard posted over 16 years ago

The article "Draw Filters" in Help shows how to draw a border around a specified edge of a grid cell.

For each cell, I would like to draw a left border, and/or a right border, or no border, depending on which column the cell is in. I could do it if, in the DrawElement method of my draw filter class, I could get a reference to the UltraGridCell that is currently being drawn. I can get a reference to the grid as drawParams.Element.Control, but I can't see how to get a reference to the UltraGridCell.

Any ideas?

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Verified Answer
Jon posted over 16 years ago

I think you can get the cell in the DrawElement method like this:

if (drawParams.Element is CellUIElement)

UltraGridCell myCell = drawParams.Element.GetContext(typeof(UltraGridCell)) as UltraGridCell;
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1467

Howard posted over 16 years ago in reply to Jon

That didn't work -- myCell is always null.
This is the code I used:
class MyDrawFilter : IUIElementDrawFilter
{
    DrawPhase IUIElementDrawFilter.GetPhasesToFilter(ref UIElementDrawParams drawParams)
    {
        if (drawParams.Element is RowCellAreaUIElement)
            return Infragistics.Win.DrawPhase.BeforeDrawBorders;
        return DrawPhase.None;
    }

    bool IUIElementDrawFilter.DrawElement(DrawPhase drawPhase, ref UIElementDrawParams drawParams)
    {
        UltraGridCell myCell = drawParams.Element.GetContext(typeof(UltraGridCell)) as UltraGridCell;
        if (myCell != null)
            throw new ApplicationException("Found non-null cell!");
        return false;
    }
}
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Daniel posted over 16 years ago in reply to Mike Saltzman

Thanks for the very good hint. I used it in a little bit different approach. I decided to 'merge' three rows into one (see the attached picture for the result). This how I did it. I return DrawPhase:BeforeDrawBorders for each second and third row (in fact, for each second and third RowCellAreaUIElement) in GetPhasesToFilter. In DrawElement I draw the borders I am interested in: - the left border of the row with the usual border color; - for all ChildElements (CellUIElements) except the last visible one, the upper border with BackColor of the cell and the upper-right corner with the usual border color; - for the last visible cell, the upper cell border (only this one) with BackColor of the cell; - the right border of the row with the usual border color. Some more work has to be done though. Getting the right color is a task itself, because one needs to go through the color hierarchy (cell, column) and whether or not the row is selected must be taken into account. But this is achievable. :) Thanks for the help, guys.
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Howard posted over 16 years ago in reply to Daniel

I actually used this to solve a somewhat similar problem with an UltraGridDocumentExporter, so my solution might not apply to you.
I included the following in the BeginExport event handler of an UltraGridDocumentExporter, which might be analogous to the InitializeLayout event of an UltraGrid:
            e.Layout.Override.BorderStyleRow = Infragistics.Win.UIElementBorderStyle.None;
           e.Layout.Override.BorderStyleCell = Infragistics.Win.UIElementBorderStyle.None;
           e.Layout.Override.RowAppearance.BorderColor = System.Drawing.Color.Transparent;
           e.Layout.Override.CellAppearance.BorderColor = System.Drawing.Color.Transparent;
I can't say I exactly understand why this worked.
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Daniel posted over 16 years ago in reply to Howard

Can you please be more specific? Which BorderColor did you set as transparent? The one of the cell or the one of the row? (I hope there is no other.) And did you still use the IUIElementDrawFilter interface? If this is no trouble for you, can you upload the the source code? Thanks.
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Daniel posted over 16 years ago in reply to Mike Saltzman

The picture shows my understanding of your solution. I am not sure I got it right. It is true that drawing white borders I will no longer have those gray lines. But I will still have broken borders, this time by some white (like the background of the cell) points, not gray as before.
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Howard posted over 16 years ago in reply to Mike Saltzman

I have had good results with setting BorderColor = System.Drawing.Color.Transparent.
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