更改单元格的背面颜色为DataGridViewComboBoxColumn

Question

我创建了一个DataGridView对象，其中的列类型为DataGridViewComboBoxColumn，以允许用户从下拉列表中选择值。例如，如果用户选择“高”，我想给组合框的背面上色。但是，它不会为组合框着色，而只会为组合框值着色。

代码是：

dgvOverallRisk.Rows[0].Cells[1].Style.ForeColor = Color.Aqua;
dgvOverallRisk.Rows[0].Cells[1].Style.BackColor = Color.Red;

它看起来像这样：

Answer 1

巧合的是，我刚刚在这里ForeColor找到了一个类似的问题。本质上相同，您有两个选择：

1. 设置FlatStyle。它可能看起来不像您想要的方式。

   theComboBoxColumn.FlatStyle = FlatStyle.Flat;
   

2. 对于我来说，这不是一个确切的解决方案，因为我使用的是Windows 8.1，从屏幕截图来看，您使用的是Windows7。它们的ComboBox控件显示风格不同，但这应该可以让您大致了解您的可能方向可以拿。处理DataGridView.CellPainting和DataGridView.EditingControlShowing事件以手动绘制ComboBox单元格。

   this.dataGridView1.CellPainting += this.dataGridView1_CellPainting;
   this.dataGridView1.EditingControlShowing += this.dataGridView1_EditingControlShowing;
   
   this.dataGridView1.Rows[0].Cells[1].Style.ForeColor = Color.DarkRed;
   this.dataGridView1.Rows[0].Cells[1].Style.BackColor = Color.Bisque;
   this.dataGridView1.Rows[1].Cells[1].Style.ForeColor = Color.SpringGreen;
   this.dataGridView1.Rows[1].Cells[1].Style.BackColor = Color.Purple;
   

    // Paint the cell when not in edit mode.
    private void dataGridView1_CellPainting(object sender, DataGridViewCellPaintingEventArgs e)
    {
      if (e.RowIndex >= 0 && e.ColumnIndex >= 0)
      {
        if (this.dataGridView1.Rows[e.RowIndex].Cells[e.ColumnIndex] is DataGridViewComboBoxCell)
        {
          var cell = this.dataGridView1.Rows[e.RowIndex].Cells[e.ColumnIndex] as DataGridViewComboBoxCell;
          var foreColor = cell.Style.ForeColor.Name == "0" ? Color.Black : cell.Style.ForeColor;

          e.Paint(e.ClipBounds, DataGridViewPaintParts.Border);
          e.Paint(e.ClipBounds, DataGridViewPaintParts.ContentBackground);

          using (Brush forebrush = new SolidBrush(foreColor))
          using (Brush backbrush = new SolidBrush(cell.Style.BackColor))
          using (StringFormat format = new StringFormat())
          {
            Rectangle rect = new Rectangle(e.CellBounds.X + 1, e.CellBounds.Y + 1, e.CellBounds.Width - 19, e.CellBounds.Height - 3);
            format.LineAlignment = StringAlignment.Center;

            e.Graphics.FillRectangle(backbrush, rect);
            e.Graphics.DrawString(cell.FormattedValue.ToString(), e.CellStyle.Font, forebrush, rect, format); 
          }

          e.Paint(e.ClipBounds, DataGridViewPaintParts.ErrorIcon);
          e.Paint(e.ClipBounds, DataGridViewPaintParts.Focus);
          e.Handled = true;
        }
      }
    }

    // Paint the cell in edit mode.
    private void dataGridView1_EditingControlShowing(object sender, DataGridViewEditingControlShowingEventArgs e)
    {
      if (this.dataGridView1.CurrentCellAddress.X == combo.DisplayIndex)
      {
        ComboBox cb = e.Control as ComboBox;
        if (cb != null)
        {
          cb.DropDownStyle = ComboBoxStyle.DropDownList;

          cb.DrawMode = DrawMode.OwnerDrawFixed;
          cb.DrawItem -= this.cb_DrawItem;
          cb.DrawItem += this.cb_DrawItem;
        }
      }
    }

    // Manually paint the combobox.
    private void cb_DrawItem(object sender, DrawItemEventArgs e)
    {
      ComboBox cb = sender as ComboBox;

      // Non-sourced vs sourced examples.
      string value = cb.Items[e.Index].ToString();
      // string value = (cb.DataSource as DataTable).Rows[e.Index].ItemArray[SourceColumnIndex];

      if (e.Index >= 0)
      {
        using (Brush forebrush = new SolidBrush(cb.ForeColor))
        using (Brush backbrush = new SolidBrush(cb.BackColor))
        {
          e.Graphics.FillRectangle(backbrush, e.Bounds);
          e.DrawBackground();
          e.DrawFocusRectangle();
          e.Graphics.DrawString(value, e.Font, forebrush, e.Bounds);
        }
      }
    }