基于原生DataGridView实现折叠/展开

最近实现一个需求，需要利用Winform原生DataGridView实现折叠/展开的效果，我这里对实现过程进行总结一下。

首先需要设计数据类结构：

    public class DataItem
    {
        public bool? Expanded { get; set; } //是否展开 null-代表子项，不可折叠/展开 true-展开 false-折叠（用于显示不同的图标）
        public bool Checked { get; set; } //是否勾选
        public long Id { get; set; }
        public string Name { get; set; }
        public string Description { get; set; }
        public bool Visible { get; set; } = true;
    }

UI设计：

第一列类型为DataGridViewImageColumn

第二列类型为DataGridViewCheckBoxColumn

加载测试数据：

        private void Form1_Load(object sender, EventArgs e)
        {

            List<DataItem> dataItems = new List<DataItem>()
            {
                new DataItem(){Expanded=true,Id=100,Name="门诊部"},
                new DataItem(){Id=101,Name="儿科门诊",Description="专为儿童服务，限制年龄"},
                new DataItem(){Id=102,Name="妇科门诊",Description="转为女性服务，限制性别"},
                new DataItem(){Id=103,Name="内科门诊",Description="内科"},
                new DataItem(){Expanded=true,Id=200,Name="住院部"},
                new DataItem(){Id=201,Name="泌尿科",Description="泌尿专科"},
                new DataItem(){Id=202,Name="骨伤科",Description="骨科专科"},
                new DataItem(){Id=203,Name="妇产科",Description="妇科+产科"},
                new DataItem(){Id=204,Name="消化科",Description="消化科"},
            };
            dataItemDataGridView.Rows.Clear();
            foreach (DataItem dataItem in dataItems)
            {
                int count = dataItemDataGridView.Rows.Count;
                dataItemDataGridView.Rows.Insert(dataItemDataGridView.Rows.Count, new object[] { !dataItem.Expanded.HasValue ? _blankImage : dataItem.Expanded.Value ? _minusImage : _plusImage, dataItem.Checked, dataItem.Name, dataItem.Description, dataItem.Id });
                dataItemDataGridView.Rows[count].Tag = dataItem;
                dataItemDataGridView.Rows[count].Visible = dataItem.Visible;
            }
        }

实现折叠/展开，选择父节点是全选/取消全选

        private void dataItemDataGridView_CellContentClick(object sender, DataGridViewCellEventArgs e)
        {
            if (e.RowIndex >= 0)
            {
                DataGridViewRowCollection rows = dataItemDataGridView.Rows;
                if (e.ColumnIndex == 0)
                {
                    Image image = rows[e.RowIndex].Cells[_imageColumnName].Value as Image;
                    bool isChecked = (bool)rows[e.RowIndex].Cells[_checkedColumnName].Value;
                    string name = rows[e.RowIndex].Cells[_nameColumnName].Value as string;
                    if (image == _plusImage)
                    {
                        dataItemDataGridView.Rows[e.RowIndex].Cells[e.ColumnIndex].Value = _minusImage;
                        int index = e.RowIndex + 1;
                        while (index < rows.Count && rows[index].Cells[_imageColumnName].Value != _plusImage && rows[index].Cells[_imageColumnName].Value != _minusImage)
                        {
                            dataItemDataGridView.Rows[index].Visible = true;
                            index++;
                        }
                    }
                    else if (image == _minusImage)
                    {
                        dataItemDataGridView.Rows[e.RowIndex].Cells[e.ColumnIndex].Value = _plusImage;
                        int index = e.RowIndex + 1;
                        while (index < rows.Count && rows[index].Cells[_imageColumnName].Value != _plusImage && rows[index].Cells[_imageColumnName].Value != _minusImage)
                        {
                            dataItemDataGridView.Rows[index].Visible = false;
                            index++;
                        }
                    }
                }
                else if (e.ColumnIndex == 1)
                {
                    bool isChecked = !(bool)rows[e.RowIndex].Cells[_checkedColumnName].Value;
                    dataItemDataGridView.Rows[e.RowIndex].Cells[_checkedColumnName].Value = isChecked;
                    DataItem dataItem = dataItemDataGridView.Rows[e.RowIndex].Tag as DataItem;
                    dataItem.Checked = isChecked;
                    Image image = rows[e.RowIndex].Cells[_imageColumnName].Value as Image;
                    if (image == _plusImage || image == _minusImage)
                    {
                        int index = e.RowIndex + 1;
                        while (index < rows.Count && rows[index].Cells[_imageColumnName].Value != _plusImage && rows[index].Cells[_imageColumnName].Value != _minusImage)
                        {
                            dataItemDataGridView.Rows[index].Cells[_checkedColumnName].Value = isChecked;
                            dataItem = dataItemDataGridView.Rows[index].Tag as DataItem;
                            dataItem.Checked = isChecked;
                            index++;
                        }
                    }
                    else
                    {
                        bool isGroupAllChecked = true;
                        int index = e.RowIndex;
                        while (index < rows.Count && rows[index].Cells[_imageColumnName].Value != _plusImage && rows[index].Cells[_imageColumnName].Value != _minusImage)
                        {
                            if (!(bool)rows[index].Cells[_checkedColumnName].Value)
                                isGroupAllChecked = false;
                            index++;
                        }
                        index = e.RowIndex - 1;
                        while (index >= 0 && rows[index].Cells[_imageColumnName].Value != _plusImage && rows[index].Cells[_imageColumnName].Value != _minusImage)
                        {
                            if (!(bool)rows[index].Cells[_checkedColumnName].Value)
                                isGroupAllChecked = false;
                            index--;
                        }
                        if (index >= 0 && (bool)rows[index].Cells[_checkedColumnName].Value != isGroupAllChecked)
                            dataItemDataGridView.Rows[index].Cells[_checkedColumnName].Value = isGroupAllChecked;
                    }
                }
            }
        }

        private void dataItemDataGridView_RowPostPaint(object sender, DataGridViewRowPostPaintEventArgs e)
        {
            if (e.RowIndex >= 0)
            {
                DataGridViewRowCollection rows = dataItemDataGridView.Rows;
                if (rows[e.RowIndex].Cells[_imageColumnName].Value == _plusImage || rows[e.RowIndex].Cells[_imageColumnName].Value == _minusImage)
                {
                    using (Brush backColorBrush = new SolidBrush(SystemColors.Control), fontBrush = new SolidBrush(SystemColors.ControlDark))
                    {
                        e.Graphics.FillRectangle(backColorBrush, e.RowBounds.X + 46, e.RowBounds.Y, dataItemDataGridView.Width, e.RowBounds.Height - 1);
                        using (Font font = new Font(Font.FontFamily.Name, Font.Size, FontStyle.Bold))
                        {
                            e.Graphics.DrawString(rows[e.RowIndex].Cells[_nameColumnName].Value as string, font, fontBrush, e.RowBounds.X + 48, e.RowBounds.Y + 2);
                        }
                    }
                }
            }
        }

        private readonly Image _plusImage = Resource.Plus;
        private readonly Image _minusImage = Resource.Minus;
        private readonly Image _blankImage = Resource.Blank;
        private readonly string _imageColumnName = "imageColumn";
        private readonly string _checkedColumnName = "checkedColumn";
        private readonly string _nameColumnName = "deptNameColumn";

其中 Resource.Plus、Resource.Minus、Resource.Blank为图标资源文件

 

 效果图：

 

 没法插入本地视频，没法演示效果。需要源代码自取：https://github.com/Freelooppowter/HierarchyForm.git