[RESOLVED] Example diffrent color for a specific value in a datagridviewcombobox column

Hi All,

I was trying to show items in a datagridview and couldn't find a complete solution to this problem.
Why? I wanted to visualize to the user the diffrence if they opted for certain values. In mycase certain choises would show phonenumbers on intranet.

To show how I wil leave the control names default. To recreate the the project. Start a windows form application, place a datagridview, and 2 bindingsources on the form

To start we need some data to show and a list to choose from.
To make a simple example I chosen to make a person class containing an Id, Name and PositionId
If the Position is a staff position it should be blue others should remain the default style
But lets start with the colorScheme Interface so we can store the colorscheme we want to show for a certain positionitem in the datagrdview
It wil need back and forecolors but also colors for teh item whilst selected. To show the Displaymember we want to see I've also added the toString property that should shadow the toString of the object.

Code:

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Public Interface IDatagridViewColorScheme

    Property ForeColor() As Color
    Property BackColor() As Color
    Property SelectionForeColor() As Color
    Property SelectionBackColor() As Color
    ReadOnly Property ToString() As String
End Interface

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and a person Interface

Code:

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Public Interface IPerson

    Property Id() As Integer
    Property Name() As String
    Property PositionId() As Integer

End Interface

---

We need a interface for the postions as well
I know we can do without interfaces but I won't, and the IDatagridViewColorScheme
will help making this code reusable.

Code:

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Public Interface IPosition

    Inherits IDatagridViewColorScheme

    Property Id() As Integer
    Property PositionDesription() As String
    Property IsManaging() As Boolean

End Interface

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Next step make the objects we need:

Code:

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Public Class Person
    Implements IPerson

    Private _Id As Integer
    Private _Name As String
    Private _PositionId As Integer


    Public Property Id() As Integer Implements IPerson.Id
        Get
            Return _Id
        End Get
        Set(ByVal value As Integer)
            _Id = value
        End Set
    End Property

    Public Property Name() As String Implements IPerson.Name
        Get
            Return _Name
        End Get
        Set(ByVal value As String)
            _Name = value
        End Set
    End Property

    Public Property PositionId() As Integer Implements IPerson.PositionId
        Get
            Return _PositionId
        End Get
        Set(ByVal value As Integer)
            _PositionId = value
        End Set
    End Property
End Class

Public Class Position

    Implements IPosition

    Private _Id As Integer
    Private _PositionDesription As String
    Private _IsManaging As Boolean
    Private _ForeColor As Color
    Private _BackColor As Color
    Private _SelectionForeColor As Color
    Private _SelectionBackColor As Color

    Public Property BackColor() As System.Drawing.Color Implements IDatagridViewColorScheme.BackColor
        Get
            Return _BackColor
        End Get
        Set(ByVal value As System.Drawing.Color)
            _BackColor = value
        End Set
    End Property

    Public Property ForeColor() As System.Drawing.Color Implements IDatagridViewColorScheme.ForeColor
        Get
            Return _ForeColor
        End Get
        Set(ByVal value As System.Drawing.Color)
            _ForeColor = value
        End Set
    End Property

    Public Property SelectionBackColor() As System.Drawing.Color Implements IDatagridViewColorScheme.SelectionBackColor
        Get
            Return _SelectionBackColor
        End Get
        Set(ByVal value As System.Drawing.Color)
            _SelectionBackColor = value
        End Set
    End Property

    Public Property SelectionForeColor() As System.Drawing.Color Implements IDatagridViewColorScheme.SelectionForeColor
        Get
            Return _SelectionForeColor
        End Get
        Set(ByVal value As System.Drawing.Color)
            _SelectionForeColor = value
        End Set
    End Property

    Public Property Id() As Integer Implements IPosition.Id
        Get
            Return _Id
        End Get
        Set(ByVal value As Integer)
            _Id = value
        End Set
    End Property

    Public Property IsManaging() As Boolean Implements IPosition.IsManaging
        Get
            Return _IsManaging
        End Get
        Set(ByVal value As Boolean)
            _IsManaging = value
        End Set
    End Property

    Public Property PositionDesription() As String Implements IPosition.PositionDesription
        Get
            Return _PositionDesription
        End Get
        Set(ByVal value As String)
            _PositionDesription = value
        End Set
    End Property

    Public Shadows ReadOnly Property ToString() As String Implements IDatagridViewColorScheme.ToString
        Get
            Return _PositionDesription
        End Get
       
    End Property
End Class

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Continue at my next post....

Now we need to build the project and do some stuff in the designer.
- Set the datasource property of bindingsource1 to the person class
- Set BindingSource2 to the positionclass.
- Set the datasource for the datagridview to bindingsource1
- choose to edit the datagridview and select the PositionIdColumn.
- Set the Columntype to datagridviewComboboxColumn
- Set the datasource for the column on bindingsource2 and select the Id for the value and the positionDescription for the displaymember of the positionIdColumn and close the columneditor
- Do some other stuff to meke the datagridview look nice (optional)

Now we need to create the data to play with
and set the bindingsources

Code:

---

Public Class Form1


    Private _DefaultCellstyle As DataGridViewCellStyle
    Private _PositionList As New List(Of Position)
    Private _PersonList As New List(Of Person)


    Private Sub Form1_Load(ByVal sender As Object, ByVal e As System.EventArgs) Handles Me.Load


        Dim PositionNames() As String = {"General employee", "Helpdesk employee", "Helpdesk manager", "Financial manager", "finance employee"}
        Dim PersonNames() As String = {"John", "Alice", "Joe", "Sue", "Jan"}
        Dim Ps As Position
        Dim Pers As Person


        _DefaultCellStyle = Me.DataGridView1.DefaultCellStyle.Clone


        For I As Integer = 0 To 4
            Ps = New Position
            Ps.PositionDesription = PositionNames(I)
            Ps.Id = I + 1
            If Ps.PositionDesription.IndexOf("manager") >= 0 Then
                Ps.IsManaging = True
                'Create a  special look for these items
                Ps.SelectionBackColor = Color.DarkBlue
                Ps.SelectionForeColor = Color.LightSkyBlue
                Ps.BackColor = Color.BlanchedAlmond
                Ps.ForeColor = Color.Blue
            Else
                'This is just to make life easy.
                Ps.SelectionBackColor = _DefaultCellStyle.SelectionBackColor
                Ps.SelectionForeColor = _DefaultCellStyle.SelectionForeColor
                Ps.BackColor = _DefaultCellStyle.BackColor
                Ps.ForeColor = _DefaultCellStyle.ForeColor
            End If
            _PositionList.Add(Ps)
        Next


        For I As Integer = 0 To 4
            Pers = New Person
            Pers.Name = PersonNames(I)
            Pers.Id = I + 1
            Pers.PositionId = I + 1
            _PersonList.Add(Pers)
        Next

        Me.BindingSource1.DataSource = _PersonList
        Me.BindingSource2.DataSource = _PositionList

    End Sub

End Class

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Now we need to override the DataGridViewComboBoxColumn with something we make our selves.

Code:

---

Imports System
Imports System.Windows.Forms
Imports System.ComponentModel

Public Class DropDownListColumn
    Inherits DataGridViewComboBoxColumn

    Public Sub New()
        'Set the type used in the DataGridView
        Me.CellTemplate = New DropDownListCell
    End Sub
End Class

Public Class DropDownListCell
    Inherits DataGridViewComboBoxCell

    Public Overrides ReadOnly Property EditType() As Type
        Get
            ' Return the type of the editing contol that
            ' the DropDownListCell uses.
            Return GetType(DropDownListEditingControl)
        End Get
    End Property

    Protected Overrides Function GetFormattedValue( _
        ByVal value As Object, ByVal rowIndex As Integer, _
        ByRef cellStyle As System.Windows.Forms.DataGridViewCellStyle, _
        ByVal valueTypeConverter As System.ComponentModel.TypeConverter, _
        ByVal formattedValueTypeConverter As System.ComponentModel.TypeConverter, _
        ByVal context As System.Windows.Forms.DataGridViewDataErrorContexts) As Object


        Dim ColorDefinition As IDatagridViewColorScheme
        'Get object that is diplayed in the DataGridView cells with default formatting
        Dim obj As Object = MyBase.GetFormattedValue( _
                value, rowIndex, cellStyle, _
                valueTypeConverter, formattedValueTypeConverter, _
                context)
        'ken de kleuren toe die voor dit item zijn gedefinieerd indien het interface IDatagridviewColumnItemColors wordt ondersteunt
        If Not IsNothing(obj) Then
            If TypeOf obj Is IDatagridViewColorScheme Then
                ColorDefinition = CType(obj, IDatagridViewColorScheme)
                cellStyle.ForeColor = ColorDefinition.ForeColor
                cellStyle.BackColor = ColorDefinition.BackColor
                cellStyle.SelectionBackColor = ColorDefinition.SelectionBackColor
                cellStyle.SelectionForeColor = ColorDefinition.SelectionForeColor
            ElseIf TypeOf obj Is ICustomTypeDescriptor Then
                ColorDefinition = CType(obj.object, IDatagridViewColorScheme)
                cellStyle.ForeColor = ColorDefinition.ForeColor
                cellStyle.BackColor = ColorDefinition.BackColor
                cellStyle.SelectionBackColor = ColorDefinition.SelectionBackColor
                cellStyle.SelectionForeColor = ColorDefinition.SelectionForeColor
            End If
        End If

        Return obj
    End Function
End Class

Public Class DropDownListEditingControl
    Inherits DataGridViewComboBoxEditingControl

    Public Sub New()
        MyBase.New()
        'Set some default properties

        'This will cause the DrawItem event to raise,
        'allowing changes to be made to the appearance
        'at run time
        Me.DrawMode = Windows.Forms.DrawMode.OwnerDrawFixed

        'Make this a DropDownList
        Me.DropDownStyle = ComboBoxStyle.DropDownList
    End Sub

    Protected Overrides Sub OnDrawItem( _
        ByVal e As System.Windows.Forms.DrawItemEventArgs)

        ' Create a rectagle the size of the item container
        Dim rec As New Rectangle(e.Bounds.X, e.Bounds.Y, e.Bounds.Width, e.Bounds.Height)
        Dim ColorDefinition As IDatagridViewColorScheme

        If Me.Enabled Then
            'If the item is being pointed to Selection it

            If e.Index > -1 Then
                Dim obj As Object = Me.Items(e.Index)
                If TypeOf obj Is IDatagridViewColorScheme Then
                    ColorDefinition = CType(obj, IDatagridViewColorScheme)
                    If (e.State And DrawItemState.Focus) = DrawItemState.Focus Then
                        e.Graphics.FillRectangle(New SolidBrush(ColorDefinition.SelectionBackColor), rec)
                    Else
                        e.Graphics.FillRectangle(New SolidBrush(ColorDefinition.BackColor), rec)
                    End If
                Else
                    If (e.State And DrawItemState.Focus) = DrawItemState.Focus Then
                        e.Graphics.FillRectangle(New SolidBrush(System.Drawing.SystemColors.Highlight), rec)
                    Else
                        e.Graphics.FillRectangle(New SolidBrush(System.Drawing.SystemColors.ControlLightLight), rec)
                    End If
                End If
            Else
                If (e.State And DrawItemState.Focus) = DrawItemState.Focus Then
                    e.Graphics.FillRectangle(New SolidBrush(System.Drawing.SystemColors.Highlight), rec)
                Else
                    e.Graphics.FillRectangle(New SolidBrush(System.Drawing.SystemColors.ControlLight), rec)
                End If
            End If
        Else
            'Grey out the box it is disablbed
            e.Graphics.FillRectangle( _
            New SolidBrush(System.Drawing.SystemColors.Control), rec)
        End If

        'If there is an item
        If e.Index > -1 Then
            Dim obj As Object = Me.Items(e.Index)
            If TypeOf obj Is IDatagridViewColorScheme Then
                ColorDefinition = CType(obj, IDatagridViewColorScheme)
                'If the item is selected Selection it           
                If (e.State And DrawItemState.Focus) = DrawItemState.Focus Then
                    Dim SelectionedText As New SolidBrush(ColorDefinition.SelectionForeColor)
                    e.Graphics.DrawString(ColorDefinition.ToString, e.Font, SelectionedText, rec)
                Else
                    Dim NormalText As New SolidBrush(ColorDefinition.ForeColor)
                    e.Graphics.DrawString(ColorDefinition.ToString, e.Font, NormalText, rec)
                End If
            Else
                If (e.State And DrawItemState.Focus) = DrawItemState.Focus Then
                    Dim SelectionedText As New SolidBrush(System.Drawing.SystemColors.HighlightText)
                    e.Graphics.DrawString(obj.ToString, e.Font, SelectionedText, rec)
                Else
                    Dim NormalText As New SolidBrush(System.Drawing.SystemColors.ControlText)
                    e.Graphics.DrawString(obj.ToString, e.Font, NormalText, rec)
                End If
            End If
        Else
            Dim NormalText As New SolidBrush(System.Drawing.SystemColors.ControlText)
            e.Graphics.DrawString("", e.Font, NormalText, rec)
        End If

    End Sub
End Class

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To implement this we need to build project first so intelisense knows out objects.

After these steps we need to go in the designer of the form and adjust it a bit
To implement the DataGridViewTextBoxColumn
We need to alter just 1 line from:
Me.PositionIdDataGridViewTextBoxColumn = New System.Windows.Forms.DropDownListColumn

Me.PositionIdDataGridViewTextBoxColumn = New Tutorial.DropDownListColumn
Where Tutorial should be replaced by the name of your application.
And Now our overriden DropDownListColumn is used
If we now run the application the items in the dropdown are colored the way we want
but we don't see them in the datagridview

continue in my next post

To make that happen we need to alter the code in the form to this

Code:

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Public Class Form1


    Private _DefaultCellstyle As DataGridViewCellStyle
    Private _Initialized As Boolean
    Private _PositionList As New List(Of Position)
    Private _PersonList As New List(Of Person)

    Private Sub Form1_Load(ByVal sender As Object, ByVal e As System.EventArgs) Handles Me.Load


        Dim PositionNames() As String = {"General employee", "Helpdesk employee", "Helpdesk manager", "Financial manager", "finance employee"}
        Dim PersonNames() As String = {"John", "Alice", "Joe", "Sue", "Jan"}
        Dim Ps As Position
        Dim Pers As Person


        _DefaultCellstyle = Me.DataGridView1.DefaultCellStyle.Clone


        For I As Integer = 0 To 4
            Ps = New Position
            Ps.PositionDesription = PositionNames(I)
            Ps.Id = I + 1
            If Ps.PositionDesription.IndexOf("manager") >= 0 Then
                Ps.IsManaging = True
                Ps.SelectionBackColor = Color.DarkBlue
                Ps.SelectionForeColor = Color.LightSkyBlue
                Ps.BackColor = Color.BlanchedAlmond
                Ps.ForeColor = Color.Blue
            Else
                'This is just to make life easy.
                Ps.SelectionBackColor = _DefaultCellstyle.SelectionBackColor
                Ps.SelectionForeColor = _DefaultCellstyle.SelectionForeColor
                Ps.BackColor = _DefaultCellstyle.BackColor
                Ps.ForeColor = _DefaultCellstyle.ForeColor
            End If
            _PositionList.Add(Ps)
        Next


        For I As Integer = 0 To 4
            Pers = New Person
            Pers.Name = PersonNames(I)
            Pers.Id = I + 1
            Pers.PositionId = I + 1
            _PersonList.Add(Pers)
        Next

        Me.BindingSource1.DataSource = _PersonList
        Me.BindingSource2.DataSource = _PositionList

    End Sub
'Make sure errors while creating the form aren't shown.
    Private Sub DatagridView1_DataError(ByVal sender As Object, ByVal e As System.Windows.Forms.DataGridViewDataErrorEventArgs) Handles DataGridView1.DataError
        'To prevent errors
        If Not _Initialized Or Me.Disposing Then
            e.ThrowException = False
        End If

    End Sub
    'We need to do some work when a row is added
    'actually we need to determine what colors the cells need to be.
    Private Sub DataGridView_RowsAdded(ByVal sender As Object, ByVal e As System.Windows.Forms.DataGridViewRowsAddedEventArgs) Handles DataGridView1.RowsAdded

        Dim RW As DataGridViewRow
        Dim Cl As DataGridViewCell
        Dim Tel As Person

        Try
            For I As Integer = e.RowIndex To e.RowIndex + e.RowCount
                RW = Me.DataGridView1.Rows(I)
                Cl = RW.Cells(PositionIdDataGridViewTextBoxColumn.Name)
                Tel = RW.DataBoundItem
                If Tel IsNot Nothing Then
                    Cl.Style.BackColor = _DefaultCellstyle.BackColor
                    Cl.Style.ForeColor = _DefaultCellstyle.ForeColor
                    Cl.Style.SelectionBackColor = _DefaultCellstyle.SelectionBackColor
                    Cl.Style.SelectionForeColor = _DefaultCellstyle.SelectionForeColor

                    For Each SoortTel As Position In _PositionList
                        'when Found duplicate the cellstyle colors to this Cell, this Is why I also filled in the default colors
                        'it saves some time at a crucial moment.
                        If SoortTel.Id = Tel.PositionId Then
                            Cl.Style.BackColor = SoortTel.BackColor
                            Cl.Style.ForeColor = SoortTel.ForeColor
                            Cl.Style.SelectionBackColor = SoortTel.SelectionBackColor
                            Cl.Style.SelectionForeColor = SoortTel.SelectionForeColor
                            Exit For
                        End If

                    Next
                End If
            Next
        Catch ex As Exception
            'Do whatever you want here, this is just a simple example
        End Try

    End Sub

    'To minimize the amount of statments the validated event will only be used to set the colors
    'if a cell is edited in this column, we can not set the cellstyle here as it is going to be edited.
    Private Sub DataGridView1_EditingControlShowing(ByVal sender As Object, ByVal e As System.Windows.Forms.DataGridViewEditingControlShowingEventArgs) Handles DataGridView1.EditingControlShowing

        Dim EditCtrl As DataGridViewComboBoxEditingControl

        If TypeOf (e.Control) Is DataGridViewComboBoxEditingControl Then
            'Er word een textbox in het grid geedit.
            EditCtrl = e.Control
            If EditCtrl.EditingControlDataGridView.CurrentCell.OwningColumn Is PositionIdDataGridViewTextBoxColumn Then
                'We are in the right column
                'Add a handler to the CellValidated so the cellstyle can be adjust to the value after editting.
                AddHandler Me.DataGridView1.CellValidated, AddressOf DataGridView1_CellValidated
            End If

        End If
    End Sub
    'And now we set the colors for the cell
    'As only the cells in the dropdownboxcolumn will
    Private Sub DataGridView1_CellValidated(ByVal sender As Object, ByVal e As System.Windows.Forms.DataGridViewCellEventArgs)

        Dim Cl As DataGridViewCell
        Dim RW As DataGridViewRow
        Dim Tel As Person

        If e.RowIndex >= 0 Then
            RW = DataGridView1.Rows(e.RowIndex)
            Cl = RW.Cells(e.ColumnIndex)
            Tel = RW.DataBoundItem

            If Tel IsNot Nothing Then
                Cl.Style.ForeColor = _DefaultCellstyle.ForeColor
                Cl.Style.BackColor = _DefaultCellstyle.BackColor
                Cl.Style.SelectionForeColor = _DefaultCellstyle.SelectionForeColor
                Cl.Style.SelectionBackColor = _DefaultCellstyle.SelectionBackColor
                For Each SoortTel As Position In _PositionList
                    If SoortTel.Id = Tel.PositionId Then
                        Cl.Style.ForeColor = SoortTel.ForeColor
                        Cl.Style.BackColor = SoortTel.BackColor
                        Cl.Style.SelectionForeColor = SoortTel.SelectionForeColor
                        Cl.Style.SelectionBackColor = SoortTel.SelectionBackColor
                        Exit For
                    End If

                Next
            End If
        End If

        RemoveHandler DataGridView1.CellValidated, AddressOf DataGridView1_CellValidated
    End Sub
End Class

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Have Fun!