I have seen a large number of people post questions regarding merging cells of a DataGridView, so I thought I would take a stab at it. Here is the Merged Cell Class.. Attached is the demo project, and image.
For vertical merging, goto www.windowsforms.net and download the "Outlook Calender Look and Feel" sample.
Code:
using System;
using System.Collections.Generic;
using System.ComponentModel;
using System.Data;
using System.Drawing;
using System.Text;
using System.Windows.Forms;
using System.Diagnostics;
using System.Drawing.Drawing2D;
namespace DataGridView_MergeDemo
{
public class HMergedCell : DataGridViewTextBoxCell
{
private int m_nLeftColumn = 0;
private int m_nRightColumn = 0;
/// <summary>
/// Column Index of the left-most cell to be merged.
/// This cell controls the merged text.
/// </summary>
public int LeftColumn
{
get
{
return m_nLeftColumn;
}
set
{
m_nLeftColumn = value;
}
}
/// <summary>
/// Column Index of the right-most cell to be merged
/// </summary>
public int RightColumn
{
get
{
return m_nRightColumn;
}
set
{
m_nRightColumn = value;
}
}
protected override void Paint(Graphics graphics, Rectangle clipBounds, Rectangle cellBounds, int rowIndex, DataGridViewElementStates cellState, object value, object formattedValue, string errorText, DataGridViewCellStyle cellStyle, DataGridViewAdvancedBorderStyle advancedBorderStyle, DataGridViewPaintParts paintParts)
{
try
{
int mergeindex = ColumnIndex - m_nLeftColumn;
int i;
int nWidth;
int nWidthLeft;
string strText;
Pen pen = new Pen(Brushes.Black);
// Draw the background
graphics.FillRectangle(new SolidBrush(SystemColors.Control), cellBounds);
// Draw the separator for rows
graphics.DrawLine(new Pen(new SolidBrush(SystemColors.ControlDark)), cellBounds.Left, cellBounds.Bottom - 1, cellBounds.Right, cellBounds.Bottom - 1);
// Draw the right vertical line for the cell
if (ColumnIndex == m_nRightColumn)
graphics.DrawLine(new Pen(new SolidBrush(SystemColors.ControlDark)), cellBounds.Right - 1, cellBounds.Top, cellBounds.Right - 1, cellBounds.Bottom);
// Draw the text
RectangleF rectDest = RectangleF.Empty;
StringFormat sf = new StringFormat();
sf.Alignment = StringAlignment.Center;
sf.LineAlignment = StringAlignment.Center;
sf.Trimming = StringTrimming.EllipsisCharacter;
// Determine the total width of the merged cell
nWidth = 0;
for (i = m_nLeftColumn; i <= m_nRightColumn; i++)
nWidth += this.OwningRow.Cells[i].Size.Width;
// Determine the width before the current cell.
nWidthLeft = 0;
for (i = m_nLeftColumn; i < ColumnIndex; i++)
nWidthLeft += this.OwningRow.Cells[i].Size.Width;
// Retrieve the text to be displayed
strText = this.OwningRow.Cells[m_nLeftColumn].Value.ToString();
rectDest = new RectangleF(cellBounds.Left - nWidthLeft, cellBounds.Top, nWidth, cellBounds.Height);
graphics.DrawString(strText, new Font("Arial", 10, FontStyle.Regular), Brushes.Black, rectDest, sf);
}
catch (Exception ex)
{
Trace.WriteLine(ex.ToString());
}
}
}// class
}
Suppose one want to merge Cell 2 and 3 in Row 0 of a Datagrid(dg_ESC) then type following code in Cell Painting event of the Datagrid
Private Sub dg_ESC_CellPainting(ByVal sender As Object, ByVal e As System.Windows.Forms.DataGridViewCellPaintingEventArgs) Handles dg_ESC.CellPainting
If e.RowIndex = 0 AndAlso (e.ColumnIndex = 2 Or e.ColumnIndex = 3) Then
Using gridBrush As Brush = New SolidBrush(Me.dg_ESC.GridColor), backColorBrush As Brush = New SolidBrush(e.CellStyle.BackColor)
Using gridLinePen As Pen = New Pen(gridBrush)
' Clear cell
e.Graphics.FillRectangle(backColorBrush, e.CellBounds)
'Bottom line drawing
e.Graphics.DrawLine(gridLinePen, e.CellBounds.Left, e.CellBounds.Bottom - 1, e.CellBounds.Right - 1, e.CellBounds.Bottom - 1)
'top line drawing
e.Graphics.DrawLine(gridLinePen, e.CellBounds.Left, e.CellBounds.Top, e.CellBounds.Right - 1, e.CellBounds.Top)
'Drawing Right line
If e.ColumnIndex = 3 Then
e.Graphics.DrawLine(gridLinePen, e.CellBounds.Right - 1, e.CellBounds.Top, e.CellBounds.Right - 1, e.CellBounds.Bottom)
End If
'Inserting text
If e.ColumnIndex = 3 Then
e.Graphics.DrawString(CType(e.Value, String), e.CellStyle.Font, Brushes.Black, e.CellBounds.X - (e.CellBounds.X / 4), e.CellBounds.Y + 5)
End If
e.Handled = True
End Using
End Using
End If
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