C#DataGridView添加序号

效果图：

 

一.Form添加全局变量

//这里的值是表格行头的初始宽度
int rowHeaderWidth = 41;

二.DataGridView添加事件

        private void dgvReconcile_RowsRemoved(object sender, DataGridViewRowsRemovedEventArgs e)
        {
            ChangeRowHeaderWidth();
        }

        private void dgvReconcile_RowsAdded(object sender, DataGridViewRowsAddedEventArgs e)
        {
            ChangeRowHeaderWidth();
        }

        private void dgvReconcile_RowHeadersWidthChanged(object sender, EventArgs e)
        {
            //这里是移动全选复选框的位置
            int offw = dgvReconcile.RowHeadersWidth - rowHeaderWidth;
            cbSelectAll.Location = new Point(cbSelectAll.Location.X + offw, cbSelectAll.Location.Y);
            rowHeaderWidth = dgvReconcile.RowHeadersWidth;
        }

        private void dgvReconcile_RowPostPaint(object sender, DataGridViewRowPostPaintEventArgs e)
        {
            if (dgvReconcile.Rows.Count > 0)
            {
                using (SolidBrush b = new SolidBrush(e.RowIndex == dgvReconcile.CurrentRow.Index ? Color.Red : dgvReconcile.RowHeadersDefaultCellStyle.ForeColor))
                {
                    e.Graphics.DrawString((Convert.ToInt32(e.RowIndex) + 1).ToString(System.Globalization.CultureInfo.CurrentCulture), e.InheritedRowStyle.Font, b, e.RowBounds.Location.X + 20, e.RowBounds.Location.Y + 4);
                }
            }
        }

其中ChangeRowHeaderWidth方法代码：

        ///<summary>
        ///计算表格序号列宽度
        ///</summar>
        private void ChangeRowHeaderWidth()
        {
            Graphics g = Graphics.FromHwnd(dgvReconcile.Handle);
            SizeF sf = g.MeasureString(dgvReconcile.Rows.Count.ToString(), dgvReconcile.Font);
            dgvReconcile.RowHeadersWidth = (int)Math.Ceiling(sf.Width + 20);
        }