[C#/WINFORM] DataGridView 클래스 : 컬럼 헤더 병합하기

TestProject.zip

다운로드

▶ MainForm.cs

using System;
using System.Drawing;
using System.Windows.Forms;

namespace TestProject
{
    /// <summary>
    /// 메인 폼
    /// </summary>
    public partial class MainForm : Form
    {
        //////////////////////////////////////////////////////////////////////////////////////////////////// Constructor
        ////////////////////////////////////////////////////////////////////////////////////////// Public

        #region 생성자 - MainForm()

        /// <summary>
        /// 생성자
        /// </summary>
        public MainForm()
        {
            InitializeComponent();

            this.Load += Form_Load;
        }

        #endregion

        //////////////////////////////////////////////////////////////////////////////////////////////////// Method
        ////////////////////////////////////////////////////////////////////////////////////////// Private

        #region 폼 로드시 처리하기 - Form_Load(sender, e)

        /// <summary>
        /// 폼 로드시 처리하기
        /// </summary>
        /// <param name="sender">이벤트 발생자</param>
        /// <param name="e">이벤트 인자</param>
        private void Form_Load(object sender, EventArgs e)
        {
            this.dataGridView.Columns.Add("01월합계", "합계");
            this.dataGridView.Columns.Add("01월평균", "평균");
            this.dataGridView.Columns.Add("02월합계", "합계");
            this.dataGridView.Columns.Add("02월평균", "평균");
            this.dataGridView.Columns.Add("03월합계", "합계");
            this.dataGridView.Columns.Add("03월평균", "평균");
            this.dataGridView.Columns.Add("04월합계", "합계");
            this.dataGridView.Columns.Add("04월평균", "평균");
            this.dataGridView.Columns.Add("05월합계", "합계");
            this.dataGridView.Columns.Add("05월평균", "평균");

            for(int i = 0; i < this.dataGridView.ColumnCount; i++)
            {
                this.dataGridView.Columns[i].Width = 70;
            }

            this.dataGridView.ColumnHeadersHeightSizeMode             = DataGridViewColumnHeadersHeightSizeMode.EnableResizing;
            this.dataGridView.ColumnHeadersHeight                     = this.dataGridView.ColumnHeadersHeight * 2;
            this.dataGridView.ColumnHeadersDefaultCellStyle.Alignment = DataGridViewContentAlignment.BottomRight;

            this.dataGridView.ColumnWidthChanged += dataGridView_ColumnWidthChanged;
            this.dataGridView.Scroll             += dataGridView_Scroll;
            this.dataGridView.Paint              += dataGridView_Paint;
            this.dataGridView.CellPainting       += dataGridView_CellPainting;
        }

        #endregion
        #region 데이터 그리드 뷰 컬럼 너비 변경시 처리하기 - dataGridView_ColumnWidthChanged(sender, e)

        /// <summary>
        /// 데이터 그리드 뷰 컬럼 너비 변경시 처리하기
        /// </summary>
        /// <param name="sender">이벤트 발생자</param>
        /// <param name="e">이벤트 인자</param>
        private void dataGridView_ColumnWidthChanged(object sender, DataGridViewColumnEventArgs e)
        {
            Rectangle headerRectangle = this.dataGridView.DisplayRectangle;

            headerRectangle.Height = this.dataGridView.ColumnHeadersHeight / 2;

            this.dataGridView.Invalidate(headerRectangle);
        }

        #endregion
        #region 데이터 그리드 뷰 스크롤시 처리하기 - dataGridView_Scroll(sender, e)

        /// <summary>
        /// 데이터 그리드 뷰 스크롤시 처리하기
        /// </summary>
        /// <param name="sender">이벤트 발생자</param>
        /// <param name="e">이벤트 인자</param>
        private void dataGridView_Scroll(object sender, ScrollEventArgs e)
        {
            Rectangle parentHeaderRectangle = this.dataGridView.DisplayRectangle;

            parentHeaderRectangle.Height = this.dataGridView.ColumnHeadersHeight / 2;

            this.dataGridView.Invalidate(parentHeaderRectangle);
        }

        #endregion
        #region 데이터 그리드 뷰 페인트시 처리하기 - dataGridView_Paint(sender, e)

        /// <summary>
        /// 데이터 그리드 뷰 페인트시 처리하기
        /// </summary>
        /// <param name="sender">이벤트 발생자</param>
        /// <param name="e">이벤트 인자</param>
        private void dataGridView_Paint(object sender, PaintEventArgs e)
        {
            string[] parentHeaderArray = { "1월", "2월", "3월", "4월", "5월" };

            for(int i = 0; i < 10; )
            {
                Rectangle cellRectangle = this.dataGridView.GetCellDisplayRectangle(i, -1, true);

                int nextCellWidth = this.dataGridView.GetCellDisplayRectangle(i + 1, -1, true).Width;

                cellRectangle.X += 1;
                cellRectangle.Y += 1;

                cellRectangle.Width = cellRectangle.Width + nextCellWidth - 2;
                cellRectangle.Height = cellRectangle.Height / 2 - 2;

                e.Graphics.FillRectangle(new SolidBrush(this.dataGridView.ColumnHeadersDefaultCellStyle.BackColor), cellRectangle);

                StringFormat stringFormat = new StringFormat();

                stringFormat.Alignment     = StringAlignment.Center;
                stringFormat.LineAlignment = StringAlignment.Center;

                e.Graphics.DrawString
                (
                    parentHeaderArray[i / 2],
                    this.dataGridView.ColumnHeadersDefaultCellStyle.Font,
                    new SolidBrush(this.dataGridView.ColumnHeadersDefaultCellStyle.ForeColor),
                    cellRectangle,
                    stringFormat
                );

                i += 2;
            }
        }

        #endregion
        #region 데이터 그리드 뷰 셀 페인트시 처리하기 - dataGridView_CellPainting(sender, e)

        /// <summary>
        /// 데이터 그리드 뷰 셀 페인트시 처리하기
        /// </summary>
        /// <param name="sender">이벤트 발생자</param>
        /// <param name="e">이벤트 인자</param>
        private void dataGridView_CellPainting(object sender, DataGridViewCellPaintingEventArgs e)
        {
            if(e.RowIndex == -1 && e.ColumnIndex > -1)
            {
                Rectangle cellRectangle = e.CellBounds;

                cellRectangle.Y += e.CellBounds.Height / 2;

                cellRectangle.Height = e.CellBounds.Height / 2;

                e.PaintBackground(cellRectangle, true);

                e.PaintContent(cellRectangle);

                e.Handled = true;
            }
        }

        #endregion
    }
}