Change font color in gridview loop

I have a gridview in asp.net that has a column displaying "Amount Due" values. I want to loop through the grid and display the values greater than zero in red font. This is what I have attempted, and it doesn't work. I get an 'object not referenced' error. Does anyone have a way to do this?

    Protected Sub Page_Load(ByVal sender As Object, ByVal e As System.EventArgs) Handles Me.Load

        Dim amtDue As Label = DirectCast(gvMyGroups.FindControl("lblAmountDue"), Label)

        For Each amtDue In gvMyGroups.Rows
            If amtDue.Text > 0 Then
                amtDue.ForeColor = Drawing.Color.DarkRed
            End If
        Next

    End Sub
wdarnellgAsked:
Who is Participating?
I wear a lot of hats...

"The solutions and answers provided on Experts Exchange have been extremely helpful to me over the last few years. I wear a lot of hats - Developer, Database Administrator, Help Desk, etc., so I know a lot of things but not a lot about one thing. Experts Exchange gives me answers from people who do know a lot about one thing, in a easy to use platform." -Todd S.

SammyCommented:
You can use the GridView's rowdatabound event to change the font
see the event here
http://msdn2.microsoft.com/en-us/library/system.web.ui.webcontrols.gridview.rowdatabound(vs.80).aspx

Page load will not do anything for you when the page is loading the controls are not built on the page

0
wdarnellgAuthor Commented:
Thanks sammy, I think I see your point. The truth is however I am having a little trouble understanding how to apply the logic to my problem. How would you use rowdatabound event to change the font color? I'll keep reading. :o)
0
wdarnellgAuthor Commented:
I feel I am so close. This code gives me a 'can't convert to double' error. Without the ctype I get the red font change, (thanks Sammy) but I only want the values greater than 0 to display in red. What am I missing?

    Protected Sub gvMyGroups_RowDataBound(ByVal sender As Object, ByVal e As System.Web.UI.WebControls.GridViewRowEventArgs) Handles gvMyGroups.RowDataBound

        Dim gvDue As GridViewRow = e.Row

        If gvDue.RowType = DataControlRowType.DataRow Then
            Dim cell As TableCell = e.Row.Cells(7)
            If CType(cell.Text, Double) > 0 Then
                cell.ForeColor = Drawing.Color.DarkRed
            End If
        End If
    End Sub
0
Cloud Class® Course: CompTIA Cloud+

The CompTIA Cloud+ Basic training course will teach you about cloud concepts and models, data storage, networking, and network infrastructure.

craskinCommented:
instead of CType(...
just use CInt(cell.Text) > 0

you could be running into trouble with casting nulls as integers or doubles, so in that case, you should nest your test for positive numbers inside an

If Not cell.Text = " " Then

block.
0
wdarnellgAuthor Commented:
Thank you craskin. I now have something that looks like:

If gvDue.RowType = DataControlRowType.DataRow Then
            Dim cell As TableCell = e.Row.Cells(8)
            If Not CDbl(cell.Text) = " " Then
                If CDbl(cell.Text) > 0 Then
                    cell.ForeColor = Drawing.Color.DarkRed
                End If
            End If
        End If

It makes sense, but the vb.net doesn't want to convert the string (.text) to an integer or double. I have very limited programming experience, and converting data types is a real blind spot in my education. :o)
It may help to know that I am using sqlserver, and the data type of the field we are trying to address is 'smallmoney'.
0
SammyCommented:
use a temp variable to hold the value and use it to check the condition

if gvDue.RowType = DataControlRowType.DataRow Then
            Dim cell As TableCell = e.Row.Cells(8)
            If Not CDbl(cell.Text) = " " Then
             Dim txtVal as Double= double.parse(cell.Text)
                If  txtVal > 0 Then
                    cell.ForeColor = Drawing.Color.DarkRed
                End If
            End If
        End If

Postback if you need any help
0

Experts Exchange Solution brought to you by

Your issues matter to us.

Facing a tech roadblock? Get the help and guidance you need from experienced professionals who care. Ask your question anytime, anywhere, with no hassle.

Start your 7-day free trial
It's more than this solution.Get answers and train to solve all your tech problems - anytime, anywhere.Try it for free Edge Out The Competitionfor your dream job with proven skills and certifications.Get started today Stand Outas the employee with proven skills.Start learning today for free Move Your Career Forwardwith certification training in the latest technologies.Start your trial today
.NET Programming

From novice to tech pro — start learning today.

Question has a verified solution.

Are you are experiencing a similar issue? Get a personalized answer when you ask a related question.

Have a better answer? Share it in a comment.