DataGridView�ｿｽR�ｿｽ�ｿｽ�ｿｽg�ｿｽ�ｿｽ�ｿｽ[�ｿｽ�ｿｽ�ｿｽﾌ連�ｿｽ�ｿｽ�ｿｽ�ｿｽ�ｿｽ體ｯ�ｿｽ�ｿｽ�ｿｽl�ｿｽﾌセ�ｿｽ�ｿｽ�ｿｽ�ｿｽ1�ｿｽﾂにまとめゑｿｽﾉは？�ｿｽm2.0�ｿｽﾌみ、C#�ｿｽAVB�ｿｽn�ｿｽF.NET TIPS

// dgvgroupedcell.cs

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

public class MyForm : Form {

  DataGridView dgv;

  // �ｿｽw�ｿｽ閧ｵ�ｿｽ�ｿｽ�ｿｽZ�ｿｽ�ｿｽ�ｿｽ�ｿｽ1�ｿｽﾂ擾ｿｽﾌセ�ｿｽ�ｿｽ�ｿｽﾌ値�ｿｽ�ｿｽ�ｿｽr
  bool IsTheSameCellValue(int column, int row) {

    DataGridViewCell cell1 = dgv[column, row];
    DataGridViewCell cell2 = dgv[column, row - 1];

    if (cell1.Value == null || cell2.Value == null) {
      return false;
    }

    // �ｿｽ�ｿｽ�ｿｽ�ｿｽ�ｿｽﾅは包ｿｽ�ｿｽ�ｿｽ�ｿｽ�ｿｽﾆゑｿｽ�ｿｽﾄセ�ｿｽ�ｿｽ�ｿｽﾌ値�ｿｽ�ｿｽ�ｿｽr
    if (cell1.Value.ToString() == cell2.Value.ToString()) {
      return true;
    } else {
      return false;
    }
  }

  // DataGridView�ｿｽ�ｿｽCellFormatting�ｿｽC�ｿｽx�ｿｽ�ｿｽ�ｿｽg�ｿｽE�ｿｽn�ｿｽ�ｿｽ�ｿｽh�ｿｽ�ｿｽ
  void dgv_CellFormatting(object sender, DataGridViewCellFormattingEventArgs e) {

    // 1�ｿｽs�ｿｽﾚにつゑｿｽ�ｿｽﾄは会ｿｽ�ｿｽ�ｿｽ�ｿｽ�ｿｽ�ｿｽﾈゑｿｽ
    if (e.RowIndex == 0)
      return;

    if (IsTheSameCellValue(e.ColumnIndex, e.RowIndex)) {
      e.Value = "";
      e.FormattingApplied = true; // �ｿｽﾈ降�ｿｽﾌ擾ｿｽ�ｿｽ�ｿｽ�ｿｽﾝ抵ｿｽﾍ不�ｿｽv
    }
  }

  // DataGridView�ｿｽ�ｿｽCellPainting�ｿｽC�ｿｽx�ｿｽ�ｿｽ�ｿｽg�ｿｽE�ｿｽn�ｿｽ�ｿｽ�ｿｽh�ｿｽ�ｿｽ
  void dgv_CellPainting(object sender, DataGridViewCellPaintingEventArgs e) {

    // �ｿｽZ�ｿｽ�ｿｽ�ｿｽﾌ会ｿｽ�ｿｽ�ｿｽ�ｿｽﾌ具ｿｽ�ｿｽE�ｿｽ�ｿｽ�ｿｽ�ｿｽ�ｿｽu�ｿｽ�ｿｽ�ｿｽE�ｿｽ�ｿｽ�ｿｽﾈゑｿｽ�ｿｽv�ｿｽﾉ設抵ｿｽ
    e.AdvancedBorderStyle.Bottom = DataGridViewAdvancedCellBorderStyle.None; �ｿｽi1�ｿｽj

    // 1�ｿｽs�ｿｽﾚゑｿｽ�ｿｽw�ｿｽb�ｿｽ_�ｿｽA�ｿｽs�ｿｽw�ｿｽb�ｿｽ_�ｿｽﾌ場合�ｿｽﾍ会ｿｽ�ｿｽ�ｿｽ�ｿｽ�ｿｽ�ｿｽﾈゑｿｽ
    if (e.RowIndex < 1 || e.ColumnIndex < 0)
      return;

    if (IsTheSameCellValue(e.ColumnIndex, e.RowIndex)) {
      // �ｿｽZ�ｿｽ�ｿｽ�ｿｽﾌ上側�ｿｽﾌ具ｿｽ�ｿｽE�ｿｽ�ｿｽ�ｿｽ�ｿｽ�ｿｽu�ｿｽ�ｿｽ�ｿｽE�ｿｽ�ｿｽ�ｿｽﾈゑｿｽ�ｿｽv�ｿｽﾉ設抵ｿｽ
      e.AdvancedBorderStyle.Top = DataGridViewAdvancedCellBorderStyle.None; �ｿｽi2�ｿｽj
    } else {
      // �ｿｽZ�ｿｽ�ｿｽ�ｿｽﾌ上側�ｿｽﾌ具ｿｽ�ｿｽE�ｿｽ�ｿｽ�ｿｽ�ｿｽ�ｿｽ�ｿｽ�ｿｽ�ｿｽﾌ具ｿｽ�ｿｽE�ｿｽ�ｿｽ�ｿｽﾉ設抵ｿｽ
      e.AdvancedBorderStyle.Top = dgv.AdvancedCellBorderStyle.Top; �ｿｽi3�ｿｽj
    }
  }

  // �ｿｽt�ｿｽH�ｿｽ[�ｿｽ�ｿｽ�ｿｽ�ｿｽLoad�ｿｽC�ｿｽx�ｿｽ�ｿｽ�ｿｽg�ｿｽE�ｿｽn�ｿｽ�ｿｽ�ｿｽh�ｿｽ�ｿｽ
  void MyForm_Load(object sender, EventArgs e) {

    // �ｿｽ�ｿｽIT�ｿｽ�ｿｽRSS�ｿｽ�ｿｽ�ｿｽ�ｿｽ�ｿｽf�ｿｽ[�ｿｽ^�ｿｽZ�ｿｽb�ｿｽg�ｿｽﾉ読み搾ｿｽ�ｿｽ�ｿｽ
    DataSet ds = new DataSet();
    ds.ReadXml("http://atmarkit.itmedia.co.jp/rss/rss.xml");

    // 3�ｿｽﾂの暦ｿｽi�ｿｽ�ｿｽ�ｿｽJ�ｿｽ�ｿｽ�ｿｽA�ｿｽt�ｿｽH�ｿｽ[�ｿｽ�ｿｽ�ｿｽ�ｿｽ�ｿｽA�ｿｽ^�ｿｽC�ｿｽg�ｿｽ�ｿｽ�ｿｽj�ｿｽﾌみゑｿｽ\�ｿｽ�ｿｽ
    dgv.ColumnCount = 3;
    dgv.Columns[0].DataPropertyName = "pubDate";
    dgv.Columns[0].HeaderText = "�ｿｽ�ｿｽ�ｿｽJ�ｿｽ�ｿｽ";
    dgv.Columns[1].DataPropertyName = "category";
    dgv.Columns[1].HeaderText = "�ｿｽt�ｿｽH�ｿｽ[�ｿｽ�ｿｽ�ｿｽ�ｿｽ";
    dgv.Columns[2].DataPropertyName = "title";
    dgv.Columns[2].HeaderText = "�ｿｽL�ｿｽ�ｿｽ�ｿｽ^�ｿｽC�ｿｽg�ｿｽ�ｿｽ";

    // �ｿｽ�ｿｽﾌ趣ｿｽ�ｿｽ�ｿｽ�ｿｽ�ｿｽ�ｿｽ�ｿｽ�ｿｽ�ｿｽ�ｿｽs�ｿｽ�ｿｽﾈゑｿｽ
    dgv.AutoGenerateColumns = false;

    // RSS�ｿｽ�ｿｽ�ｿｽ�ｿｽ<item>�ｿｽv�ｿｽf�ｿｽ�ｿｽ�ｿｽ�ｿｽ�ｿｽ�ｿｽ�ｿｽf�ｿｽ[�ｿｽ^�ｿｽ\�ｿｽ[�ｿｽX�ｿｽﾆゑｿｽ�ｿｽﾄ使�ｿｽp
    dgv.DataSource = ds.Tables["item"];
  }

  // �ｿｽt�ｿｽH�ｿｽ[�ｿｽ�ｿｽ�ｿｽﾌコ�ｿｽ�ｿｽ�ｿｽX�ｿｽg�ｿｽ�ｿｽ�ｿｽN�ｿｽ^
  public MyForm() {
    dgv = new DataGridView();
    dgv.Dock = DockStyle.Fill;
    dgv.CellFormatting += new DataGridViewCellFormattingEventHandler(dgv_CellFormatting);
    dgv.CellPainting += new DataGridViewCellPaintingEventHandler(dgv_CellPainting);
    this.Controls.Add(dgv);
    this.Size = new Size(480, 240);
    this.Load += new EventHandler(MyForm_Load);
  }
}

class Program {
  [STAThread]
  static void Main() {
    Application.Run(new MyForm());
  }
}

// �ｿｽR�ｿｽ�ｿｽ�ｿｽp�ｿｽC�ｿｽ�ｿｽ�ｿｽ�ｿｽ�ｿｽ@�ｿｽFcsc dgvgroupedcell.cs