c# - ComboBoxCell 中的自定义绘制项

Question

我正在尝试使用 DrawItem 事件在 DataGridView 的 ComboBoxCell 中绘制项目。以下是我的代码。

更新代码:

private void dgv_EditingControlShowing(object sender, DataGridViewEditingControlShowingEventArgs e)
    {
        int index = dgv.CurrentCell.ColumnIndex;
        if (index == FormatColumnIndex)
        {
            var combobox = e.Control as ComboBox;
            if (combobox == null)
                return;
            combobox.DrawMode = DrawMode.OwnerDrawFixed;
            combobox.DrawItem -= combobox_DrawItem;
            combobox.DrawItem += new DrawItemEventHandler(combobox_DrawItem);
        }            
    }

void combobox_DrawItem(object sender, DrawItemEventArgs e)
    {
        if (e.Index < 0)
        {
            return;
        }
        int index = dgv.CurrentCell.RowIndex;
        if (index == e.Index)
        {
            DataGridViewComboBoxCell cmbcell = (DataGridViewComboBoxCell)dgv.CurrentRow.Cells["ProductFormat"];

            string productID = dgv.Rows[cmbcell.RowIndex].Cells["ProductID"].Value.ToString();

                string item = cmbcell.Items[e.Index].ToString();
                if (item != null)
                {
                    Font font = new System.Drawing.Font(FontFamily.GenericSansSerif, 8);
                    Brush backgroundColor;
                    Brush textColor;

                    if (e.State == DrawItemState.Selected)
                    {
                        backgroundColor = SystemBrushes.Highlight;
                        textColor = SystemBrushes.HighlightText;
                    }
                    else
                    {
                        backgroundColor = SystemBrushes.Window;
                        textColor = SystemBrushes.WindowText;
                    }
                    if (item == "Preferred" || item == "Other")
                    {
                        font = new Font(font, FontStyle.Bold);
                        backgroundColor = SystemBrushes.Window;
                        textColor = SystemBrushes.WindowText;
                    }                        


                    if (item != "Select" && item != "Preferred" && item != "Other")
                        e.Graphics.DrawString(item, font, textColor, new Rectangle(e.Bounds.X, e.Bounds.Y, e.Bounds.Width, e.Bounds.Height));
                    else
                        e.Graphics.DrawString(item, font, textColor, e.Bounds);
                }
            }
        }
    }

项目显示正确，但下拉菜单似乎不合适，看起来很别扭。

此外，当我将鼠标悬停在下拉项上时，它们似乎又被重新绘制了一遍，这使它们看起来更暗、更模糊。我怎样才能解决这个问题？谢谢。

Answer 1

您的绘图例程看起来像是将网格的 RowIndex 与 ComboBox 项目集合的 e.Index 混淆了。不同的东西。

尝试删除这个:

// int index = dgv.CurrentCell.RowIndex;
// if (index == e.Index) {

就模糊而言，添加以下行来修复:

void combobox_DrawItem(object sender, DrawItemEventArgs e) {
  e.DrawBackground();