Hi Steve,

A DrawFilter affects the drawing level of the grid. So there are no properties set on the grid itself, it just traps when the cell is about to paint on the screen and says - use this color instead of the one you were going to use. it's a lot more efficient since it only affects the cells that are actually visible on-screen.

Hi Mike,

This is amazing! This DrawFilter works seemlessly (I never used this before and honestly still don't understand how it works but will study and find out because it may help us in other area - we have a very old code base (since 2010) written by many people and UI is extremely slow overall). But this particular Grid painting time is now down to 1 minute, same as if I don't have the entire foreach cell loop.

Thank you very much for you code.

-Steve

Hi Steve, 

There is a Format property on the column, so you could use that to control the number of digits. But Format just calls the ToString method on the value of the cell and passes in the format. So the DotNet framework handles this, it's not something we have any control over, and so we can't add support for colors. 

BTW... the grid does not "paint every cell no matter what". InitializeRow fires for all of the rows, but the rows are not painting unless they are in view. So that means you could achieve what you want using the column's Format property and color the cell's text using a DrawFilter and that would be a lot more efficient.

This would be a pretty simple DrawFilter. Something like this: 

 public class MyDrawFilter : IUIElementDrawFilter
 {
     public bool DrawElement(DrawPhase drawPhase, ref UIElementDrawParams drawParams)
      {
           if (drawParams.Element is EditorWithTextDisplayTextUIElement)
           {
                var cell = drawParams.Element.GetContext(typeof(UltraGridCell)) as UltraGridCell;
                if (null != cell)
               {
                     if (cell.Value is int &&
                     (int)cell.Value < 0)
                     {
                          drawParams.AppearanceData.ForeColor = System.Drawing.Color.Red;
                     }
                }
           }

          return false;
      }
     public DrawPhase GetPhasesToFilter(ref UIElementDrawParams drawParams)
      {
           if (drawParams.Element is EditorWithTextDisplayTextUIElement)
                return DrawPhase.BeforeDrawForeground;
          return DrawPhase.None;
      }
 }

You hook it up to the grid like this: 

this.ultraGrid1.DrawFilter = new MyDrawFilter();

I am actually troubled by this whole foreach cell loop code too. It should never be written under any circumstance.

Since Infragistics code has to paint every cell no matter what, why cannot you just give us a column format property and we set it to something like 

        GridColumnFormat = "###,##0;[Red]-###,##0";

and let the Infragistics code paint cell properly?

As for your suggestion of using a common Appearance object instead of accessing each appearance object per cell, it did improve a little bit on runtime: with a 2 level (yes a 3-level is not workable as it is toooo slow so I forced a requirement change to a 2 level) hierarchical grid (first band 7k rows and second 10k), UI rendering time dropped from 3.7 minutes to 3.6 minutes. Not exactly exciting. In comparison, if I remove the loop code for this red cell handling  altogether, the painting time dropped to 1 minute (still kinda slow IMO).

I hope you have a better solution for this "Negative cell needs to show Red" problem.

Thanks

Steve