需要实现dataGridView中的 CellMouseMove、DragDrop、CellMouseDown、SelectionChanged、DragEnter 5个事件。

代码如下：

        int selectionIdx;
        //下方为鼠标拖动表格事件
        private void dataGridView1_CellMouseMove(object sender, DataGridViewCellMouseEventArgs e)
        {
            if ((e.Clicks < 2) && (e.Button == MouseButtons.Left))
            {
                if ((e.ColumnIndex == -1) && (e.RowIndex > -1))
                    dataGridView1.DoDragDrop(dataGridView1.Rows[e.RowIndex], DragDropEffects.Move);
            }
        }

        private void dataGridView1_DragDrop(object sender, DragEventArgs e)
        {
            int idx = GetRowFromPoint(e.X, e.Y);

            if (idx < 0) return;

            if (e.Data.GetDataPresent(typeof(DataGridViewRow)))
            {
                DataGridViewRow row = (DataGridViewRow)e.Data.GetData(typeof(DataGridViewRow));
                dataGridView1.Rows.Remove(row);
                dataGridView1.Rows.Insert(idx, row);
                selectionIdx = idx;
            }
        }
//添加获取行坐标方法
        private int GetRowFromPoint(int x, int y)
        {
            for (int i = 0; i < dataGridView1.RowCount; i++)
            {
                Rectangle rec = dataGridView1.GetRowDisplayRectangle(i, false);

                if (dataGridView1.RectangleToScreen(rec).Contains(x, y))
                    return i;
            }

            return -1;
        }

        private void dataGridView1_CellMouseDown(object sender, DataGridViewCellMouseEventArgs e)
        {
            if (e.RowIndex >= 0)
                selectionIdx = e.RowIndex;
        }

        private void dataGridView1_SelectionChanged(object sender, EventArgs e)
        {
            if ((dataGridView1.Rows.Count > 0) && (dataGridView1.SelectedRows.Count > 0) && (dataGridView1.SelectedRows[0].Index != selectionIdx))
            {
                if (dataGridView1.Rows.Count <= selectionIdx)
                    selectionIdx = dataGridView1.Rows.Count - 1;
                dataGridView1.Rows[selectionIdx].Selected = true;
                dataGridView1.CurrentCell = dataGridView1.Rows[selectionIdx].Cells[0];
            }
        }

        private void dataGridView1_DragEnter(object sender, DragEventArgs e)
        {
            e.Effect = DragDropEffects.Move;
        }