cells forecolor and backcolor taking random values on refresh

[Yaroslav]

Hi, using the sample provided on the link GridView, formatting cells I'm trying to dinamically change cells foreground.

The color is changed indeed but then I'm having a big problem. When I scroll the grid, either horizontally or vertically, diferent cells, other than the one I changed, change also their foreground color to the one I'm using. Same problem with the background color of the cell.

Here is a code snippet showing the funcionality I'm trying to achieve, very similar to the sample provided on the link.

Select Case e.Column.Name
    Case "TestID"
       Select Case e.Row.Cells("Status").Value
            Case 1
                e.CellElement.ForeColor = Color.Green
            Case Else
                e.CellElement.ResetValue(LightVisualElement.ForeColorProperty, Telerik.WinControls.ValueResetFlags.Local)
    End Select
End Select

[erwin]

Hi Yaroslav,

due to the internal reuse of Cells in the Grid, once you use the CellFormatting Event, you have to reset changes to all cells.

In your case, you have to call the Reset Function for all Cells not just for Column 'TestID'.

Regards
Erwin

[Yaroslav]

Thanks, you saved my day.

And just to extend a little bit more the question. I created a enum set to declare several colors, here is a code snippet

    Public Enum ColorStatus
        First = &HFF1308&
        Second = &HFFFFFF&
    End Enum

e.CellElement.RowInfo.Cells("Status").Style.ForeColor = System.Drawing.ColorTranslator.FromHtml(ColorStatus.First)

Then I apply one of the colors to a cell (the one that was causing problems) but the ColorTranslator.FromHtml is not recognizing the colors. Any clue?

[erwin]

Glad I could be of help. Can't help you with the second question since I'm a C# guy.

According to
http://msdn.microsoft.com/de-de/library/system.drawing.colortranslator.fromhtml.aspx
you have to supply a string value.

Regards
Erwin

[Yaroslav]

Thanks again, I will give it a try

[Ivan Petrov]

Hello guys,

Thank you both for writing.

I am glad you have been able to found your way through Yaroslav's first problem. 
On the second problem. First, some background. A color value needs 32 bits to store its value. Integer values are 32 bits, but one is reserved for the sign and an integer cannot store all possible color values. You can store only the RGB values of the color in an int, but when you format it into a color string, it will be transformed with leading zeroes which is how it is represented in memory and you will get a transparent color. For this purpose you need a unsigned integer where all 32 bits are used for storing data. Unfortunately, you cannot use unsigned integers as values for an enumeration. A possible solution would be to store the RGB values in a enumeration and then to add it to a unsigned integer with leading FF instead of 00 so you would get the actual color. Here is an example of this:

Enum ColorStatus
  First = &Hff1308
  Second = &Hffffff
End Enum

Dim colorValue As UInteger = &HFF000000UI + CInt(ColorStatus.First)
e.CellElement.RowInfo.Cells("Status").Style.ForeColor = System.Drawing.ColorTranslator.FromHtml(String.Format("#{0:X}", colorValue))

I hope this will be useful for you. Should you have further questions, I would be glad to help.

Greetings,
Ivan Petrov
the Telerik team

[Yaroslav]

Hi, I unsubscribed from this thread but came back to it to refresh the reset issue and saw the Ivan Petrov answer...thanks very much! it is perfectly working now, I can use enumerates to handle my different status colors for all the app.

[Yaroslav]

I'm having again the refresh issue on my grids. Whenever I scroll right and then left many of the icons I'm displaying on the cells are repeated on other cells. This is causing me problems as not only is drawing icons where there none but also where I have inactive cells (grayed icon) is painting the enabled icon, but the button remains grayed.

Tried ther reset recommendation from Erwin but is not working.

Thanks!

[Stefan]

Hello Yaroslav,

Thank you for writing back.

The ResetValue method should reset the styles for the cells and prevent such a behavior. Since you are mentioning this does not work in your case, I will need to ask you for a sample project demonstrating this issue, so I can investigate it locally and provide you with adequate support. You will need to open a new support ticket, where attachments are allowed. Please mention this forum thread in the ticket as well.
 
Regards,
Stefan
the Telerik team