Datagridview single cell color

[TaleOfTimes]

Hello all,

 

this is pissing me off. I want to change the style of a single cell in a datagridview control. I'm using this

 

datagridview1.Rows[0].Cells["Column1"].Style.Backcolor = Color.Blue;

 

no compilation errors, but then at runtime it completely ignores it and keeps the background color white. The only way I can get anything to happen is by settings the DefaultCellStyle on the column, but I dont want to change the entire column, just ONE cell

 

thanks

[TaleOfTimes]

Ok I found the problem. I have a databinding on the datagridview. When I use AcceptChanges on a table in the dataset it erases the cell styles. Why?

[techmanbd]

I just finished doing this exact thing. You need to make a special class to repaint the cell, and also call it in the program for the datagrid. Here is my code you can look at and hopefully this will help get you started. In the Class ColoredTextBoxColumnResult is where you do the comparison to change the color of the cell. You see mine, but I am sure you will have different comparisons. But I left mine in there as an example.

 

You can also read this to give you a better explanation of why it is done this way http://msdn2.microsoft.com/en-us/library/aa289506(VS.71).aspx

 

this routine formats the columns for the colors. Calls from the class I put in below.

 

When I set up everything say at load. You need to call like so.

me.FormatGridColumns()
me.CompleteDataGrid()

 

Private Sub FormatGridColumns()
       Me.datResult.TableStyles.Clear()
       Dim tsProducts As New DataGridTableStyle
       Dim tbcChan As DataGridTextBoxColumn
       Dim ctbcResult(12) As ColoredTextBoxColumnResult
       Dim intLoop As Integer
       tbcChan = New DataGridTextBoxColumn
       With tbcChan
           .MappingName = "Channels"
           .HeaderText = "Channels"
           .Width = 100
           .Alignment = HorizontalAlignment.Center
       End With
       If Me.PT.arryFreqs.Count <> 0 Then
           For intLoop = 1 To Me.PT.arryFreqs.Count
               ctbcResult(intLoop) = New ColoredTextBoxColumnResult
               With ctbcResult(intLoop)
                   .MappingName = "freq" & intLoop.ToString
                   .HeaderText = Me.PT.arryFreqs.Item(intLoop - 1)
                   .Width = 100
                   .Alignment = HorizontalAlignment.Center
               End With
           Next
       End If
       tsProducts.MappingName = "results"
       tsProducts.GridColumnStyles.Add(tbcChan)
       If Me.PT.arryFreqs.Count <> 0 Then
           For intLoop = 1 To Me.PT.arryFreqs.Count
               tsProducts.GridColumnStyles.Add(ctbcResult(intLoop))
           Next
       End If
       Me.datResult.TableStyles.Add(tsProducts)
       tsProducts.Dispose()
   End Sub

 

 

Set up my datagrid

Private Sub CompleteDataGrid()
       Me.datResult.DataSource = Nothing
       Me.datResult.CaptionText = "Results in dB"
       Dim objCellVal As Object
       Dim intL As Integer
       Dim intLC As Integer
       Dim strR As String
       Dim dt As New DataTable
       Dim dr As DataRow
       Dim dv As DataView = New DataView
       With dt
           .TableName = "results"
           .Columns.Add("Channels")
           For intL = 1 To PT.arryFreqs.Count
               .Columns.Add("freq" & intL.ToString)
           Next
       End With
       With dv
           .Table = dt
           For intL = 1 To PT.arryChansTested.Count
               dr = .Table.NewRow
               .Table.Rows.Add(dr)
           Next
       End With
       With Me.datResult
           .DataSource = dv
           For intL = 0 To (PT.arryChansTested.Count - 1)
               For intLC = 0 To (PT.arryFreqs.Count)
                   If intLC = 0 Then
                       strR = PT.arryChansTested(intL)
                       objCellVal = strR.Substring(0, strR.IndexOf(":"))
                   Else
                       objCellVal = 0
                   End If
                   .Item(intL, intLC) = objCellVal
               Next
           Next
       End With
   End Sub

 

 

 

repaint class

Public Class ColoredTextBoxColumnResult
   Inherits DataGridTextBoxColumn
   Dim passthruVar As PassThru
   Protected Overloads Overrides Sub Paint(ByVal graph As Graphics, _
        ByVal rectbounds As Rectangle, ByVal curmngrSrc As _
        CurrencyManager, ByVal RowNumber As Integer, ByVal _
        ForeColorBrush As Brush, ByVal BackColorBrush As Brush, _
        ByVal AlignmentRight As Boolean)

       Dim ObjVal As Object
       ObjVal = Me.GetColumnValueAtRow(curmngrSrc, RowNumber)
       If Not (IsNothing(ObjVal) Or IsDBNull(ObjVal)) Then
           If IsNumeric(ObjVal) Then
               Dim dblUL As Double
               Dim strMap As String = Me.MappingName
               Dim cellValue As Double = Convert.ToDouble(ObjVal)
               Dim intCol As Integer = Convert.ToInt32(strMap.Substring(strMap.IndexOf("q") + 1))
               If intCol <> 0 Then
                   dblUL = Convert.ToDouble(Me.passthruVar.arryDBs(intCol - 1))
               End If
               If dblUL > 0 Then
                   dblUL = (dblUL * -1)
               End If
               If cellValue = 0 Then
                   BackColorBrush = Brushes.LightGray
                   ForeColorBrush = Brushes.Black
               ElseIf (cellValue > dblUL) Or (cellValue < -90) Then
                   BackColorBrush = Brushes.Red
                   ForeColorBrush = Brushes.Black
               Else
                   BackColorBrush = Brushes.Green
                   ForeColorBrush = Brushes.Black
               End If
           Else
               BackColorBrush = Brushes.Gray
               ForeColorBrush = Brushes.Black
           End If
       Else
           BackColorBrush = Brushes.Gray
           ForeColorBrush = Brushes.Black
       End If


       ' Call Paint from the base class to 
       ' accomplish the actual drawing.
       MyBase.Paint(graph, rectbounds, curmngrSrc, RowNumber, _
           BackColorBrush, ForeColorBrush, AlignmentRight)
   End Sub

[TaleOfTimes]

Thanks for the reply!

 

I also found that putting

datagridview1.Rows[e.RowIndex].Cells["Column1"].Style.Backcolor = Color.Blue;

in the RowPostPaint event also gets the job done although it is not the most efficient way.

 

Thank again

[techmanbd]

Hmm. I was looking in my applications and realized I don't have the datagridview1. Are you running 2005 version? I am running VS 2003 version. That is probably why I needed to make that class.