Vb.net 在DataGridViewComboBox下拉列表中设置特定项的颜色_Vb.net_Datagridview_Datagridviewcombobox

Vb.net 在DataGridViewComboBox下拉列表中设置特定项的颜色

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Vb.net 在DataGridViewComboBox下拉列表中设置特定项的颜色,vb.net,datagridview,datagridviewcombobox,Vb.net,Datagridview,Datagridviewcombobox,在下面的示例中，如何突出显示（更改背景色）下拉列表中特定项目？具体来说，我指的是DataGridViewComboBox的“下拉列表”中的项目我想为用户突出显示错误选择的特定项目请提供vb.net中的工作代码示例 Private Sub Form1_Load(sender As Object, e As EventArgs) Handles MyBase.Load Dim dt As New DataTable dt.Columns.Add("id", GetType(In

在下面的示例中，如何突出显示（更改背景色）下拉列表中特定项目？具体来说，我指的是DataGridViewComboBox的“下拉列表”中的项目

我想为用户突出显示错误选择的特定项目

请提供vb.net中的工作代码示例

Private Sub Form1_Load(sender As Object, e As EventArgs) Handles MyBase.Load
    Dim dt As New DataTable

    dt.Columns.Add("id", GetType(Integer))
    dt.Columns.Add("list", GetType(String))
    dt.Columns.Add("goodChoice", GetType(Boolean))

    dt.Rows.Add(10, "Lemon")
    dt.Rows.Add(20, "Apple")
    dt.Rows.Add(30, "Star Fruit", False)
    dt.Rows.Add(40, "Orange")

    Dim newColumn As New DataGridViewComboBoxColumn()
    With newColumn
        .HeaderText = "Choices"
        .Name = "Choices"
        .DataSource = dt
        .DisplayMember = "list"
        .ValueMember = "id"
    End With
    DataGridView1.Columns.Add(newColumn)
End Sub

尝试处理

EditingControlShowing

事件以订阅

组合框.DrawItem

事件。在这个事件处理程序中，您将获取底层的

数据表

数据源

。当该项目的

goodChoice

为

False

且该项目不是焦点项目时，填充其背景色

Private Sub DataGridView1_EditingControlShowing(sender As Object, e As DataGridViewEditingControlShowingEventArgs) Handles DataGridView1.EditingControlShowing
    If TypeOf e.Control Is ComboBox Then
        Dim cb As ComboBox = TryCast(e.Control, ComboBox)
        cb.DrawMode = DrawMode.OwnerDrawFixed
        RemoveHandler cb.DrawItem, AddressOf DrawGridComboBoxItem
        AddHandler cb.DrawItem, AddressOf DrawGridComboBoxItem
    End If
End Sub

Private Sub DrawGridComboBoxItem(sender As Object, e As DrawItemEventArgs)
    If e.Index <> -1 Then

        e.DrawBackground()

        Dim cb As ComboBox = TryCast(sender, ComboBox)
        Dim dt As DataTable = TryCast(cb.DataSource, DataTable)

        If (e.State And DrawItemState.Focus) <> DrawItemState.Focus AndAlso cb.DroppedDown Then
            If dt.Rows(e.Index).Item("goodChoice") Then
                e.Graphics.FillRectangle(Brushes.White, e.Bounds)
            Else ' Added for follow-up question.
                e.Graphics.FillRectangle(Brushes.Red, e.Bounds)
            End If
        End If

        e.Graphics.DrawString(dt.Rows(e.Index).Item("Name"), e.Font, Brushes.Black, e.Bounds)

        e.DrawFocusRectangle()
    End If
End Sub

然后通过手动绘制背景来使用该颜色：

Private Sub DataGridView1_CellPainting(sender As Object, e As DataGridViewCellPaintingEventArgs) Handles DataGridView1.CellPainting
    If e.RowIndex >= 0 And e.ColumnIndex >= 0 Then
        If TypeOf DataGridView1.Rows(e.RowIndex).Cells(e.ColumnIndex) Is DataGridViewComboBoxCell Then
            Dim cell As DataGridViewComboBoxCell = DataGridView1.Rows(e.RowIndex).Cells(e.ColumnIndex)
            Dim color As Color = If(cell.Style.ForeColor.Name = "0", Color.Black, cell.Style.ForeColor)

            Using backbrush = New SolidBrush(cell.Style.BackColor)
                Using brush = New SolidBrush(color)
                    Using format = New StringFormat()
                        e.Paint(e.ClipBounds, DataGridViewPaintParts.Background)
                        e.Paint(e.ClipBounds, DataGridViewPaintParts.Border)
                        e.Paint(e.ClipBounds, DataGridViewPaintParts.ContentBackground)
                        e.Paint(e.ClipBounds, DataGridViewPaintParts.ErrorIcon)
                        e.Paint(e.ClipBounds, DataGridViewPaintParts.Focus)
                        e.Paint(e.ClipBounds, DataGridViewPaintParts.SelectionBackground)

                        format.LineAlignment = StringAlignment.Center

                        Dim rect = New Rectangle(e.CellBounds.X + 1, e.CellBounds.Y + 1, e.CellBounds.Width - 19, e.CellBounds.Height - 3)

                        e.Graphics.FillRectangle(backbrush, rect)
                        e.Graphics.DrawString(cell.FormattedValue, e.CellStyle.Font, brush, e.CellBounds, format)
                        e.Handled = True
                    End Using
                End Using
            End Using
        End If
    End If
End Sub