DataGridView Merging Cells

Yesterday, a colleague asked me DataGridView the problem of cell merging, and at first I imagined that I would figure out the rectangle of two cells,
Then use e directly. Graphics.FillRectangle (BackColorBrush, rectangle) fills the background color from the new one, and then draws the displayed characters, of course this idea is not feasible.

Here is the method I wrote a cell merge, in fact, this method is not good, but it seems to be a combination of cells, in fact, the actual DataGridView column structure is not changed, and this redraw method is not editable, so I still recommend if you encounter the problem of merging cells, It's better not to use DataGridView.
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Code section:

Using System;
Using System.Collections.Generic;
Using System.ComponentModel;
Using System.Data;
Using System.Drawing;
Using System.Linq;
Using System.Text;
Using System.Windows.Forms;

Namespace Windowsdemo
{
public partial class Datagridviewmergecell:form
{
Public Datagridviewmergecell ()
{
InitializeComponent ();
Init ();
}

private void Datagridviewmergecell_load (object sender, EventArgs e)
{
int rowIndex = view. Rows.Add ();
DataGridViewRow row = view. Rows[rowindex];
Row. cells["Value"]. Value = "BBB";
Row. cells["Name"]. Value = "AAA";
Row. cells["Price"]. Value = "BBB";
Row. cells["Num"]. Value = "AAA";
RowIndex = view. Rows.Add ();
row = view. Rows[rowindex];
Row. cells["Value"]. Value = "BBB";
Row. cells["Name"]. Value = "AAA";
Row. cells["Price"]. Value = "BBB";
Row. cells["Num"]. Value = "AAA";
RowIndex = view. Rows.Add ();
row = view. Rows[rowindex];
Row. cells["Value"]. Value = "BBB";
Row. cells["Name"]. Value = "AAA";
Row. cells["Price"]. Value = "BBB";
Row. cells["Num"]. Value = "AAA";
RowIndex = view. Rows.Add ();
row = view. Rows[rowindex];
Row. cells["Value"]. Value = "BBB";
Row. cells["Name"]. Value = "AAA";
Row. cells["Price"]. Value = "BBB";
Row. cells["Num"]. Value = "AAA";
RowIndex = view. Rows.Add ();
row = view. Rows[rowindex];
Row. cells["Value"]. Value = "BBB";
Row. cells["Name"]. Value = "AAA";
Row. cells["Price"]. Value = "BBB";
Row. cells["Num"]. Value = "AAA";


}

private void Init () {

View. Allowusertoaddrows = false;
View. Columnheadersvisible = false;
View. AutoGenerateColumns = false;
View. AutoSize = false;
View. Rowheadersvisible = false;
View. Gridcolor = System.Drawing.ColorTranslator.FromHtml ("#F8F8FF");
View. Columnheadersheight = 60;

View. autoSizeColumnsMode = Datagridviewautosizecolumnsmode.none;
View. Columnheadersborderstyle = Datagridviewheaderborderstyle.single;
View. Columns.Add (New Datagridviewtextboxcolumn () {name = "name", HeaderText = "Body", Width = all, ReadOnly = True,visible = True , AutoSizeMode = Datagridviewautosizecolumnmode.none});
View. Columns.Add (New Datagridviewtextboxcolumn () {Name = "value", HeaderText = "", Width = new, ReadOnly = True, Visible = True , AutoSizeMode = Datagridviewautosizecolumnmode.none});
View. Columns.Add (New Datagridviewtextboxcolumn () {Name = "price", HeaderText = "Body", Width =, ReadOnly = true, Visible = tr UE, AutoSizeMode = Datagridviewautosizecolumnmode.none});
View. Columns.Add (New Datagridviewtextboxcolumn () {Name = "num", HeaderText = "", Width = new, ReadOnly = True, Visible = True, AutoSizeMode = Datagridviewautosizecolumnmode.fill});
View. CellPainting-= new Datagridviewcellpaintingeventhandler (view_cellpainting);
View. CellPainting + = new Datagridviewcellpaintingeventhandler (view_cellpainting);
}


void View_cellpainting (object sender, DataGridViewCellPaintingEventArgs e)
{
if (E.rowindex = = 1 && e.columnindex = = 1)
{
Brush BackColorBrush = new SolidBrush (E.cellstyle.backcolor);
E.paint (E.cellbounds, Datagridviewpaintparts.all);
E.graphics.fillrectangle (BackColorBrush, e.cellbounds);
Draw the background color (selected)
if (e.state = = (Datagridviewelementstates.displayed | datagridviewelementstates.selected | datagridviewelementstates.visible))
E.paintbackground (E.cellbounds, false);
Draw the original text separately and now change the color of the text
Brush fontcolor = new SolidBrush (E.cellstyle.forecolor);
E.graphics.drawstring ("", this. Font, FontColor, E.cellbounds, Stringformat.genericdefault);
Draw the bottom border line
Brush Gridbrush = new SolidBrush (This.view.GridColor);
Pen pen = new Pen (gridbrush);
E.graphics.drawline (pen, E.cellbounds.left, E.cellbounds.bottom-1,
E.cellbounds.right-1, e.cellbounds.bottom-1);
DataGridViewCell cell = This.view.rows[e.rowindex]. Cells[e.columnindex];

Cell. Value = "";
E.handled = true;
}
if (E.rowindex = = 1 && e.columnindex = = 2)
{
Brush BackColorBrush = new SolidBrush (E.cellstyle.backcolor);
E.paint (E.cellbounds, Datagridviewpaintparts.all);
E.graphics.fillrectangle (BackColorBrush, e.cellbounds);
Draw the background color (selected)
if (e.state = = (Datagridviewelementstates.displayed | datagridviewelementstates.selected | datagridviewelementstates.visible))
E.paintbackground (E.cellbounds, true);
Draw the original text separately and now change the color of the text
Brush fontcolor = new SolidBrush (E.cellstyle.forecolor);
E.graphics.drawstring ("", this. Font, FontColor, E.cellbounds, Stringformat.genericdefault);
Draw the bottom border line
Brush Gridbrush = new SolidBrush (This.view.GridColor);
Pen pen = new Pen (gridbrush);

E.graphics.drawline (pen, E.cellbounds.left, E.cellbounds.bottom-1,
E.cellbounds.right-1, e.cellbounds.bottom-1);

Draw right Border line
E.graphics.drawline (pen, e.cellbounds.right-1,
E.cellbounds.top, E.cellbounds.right-1,
E.CELLBOUNDS.BOTTOM-1);
DataGridViewCell cell = This.view.rows[e.rowindex]. Cells[e.columnindex];
Cell. Value = "";
Cell. Tag = "CCCCC";
Rectangle Rectanle = e.cellbounds;
Rectanle. X = Rectanle. X-15;
Rectanle. Y = Rectanle. Y + 5;
It's important to note that I'm not using e.graphics cause this is the only one that can be drawn in the current cell
And I was building a drawing graphics object on top of the DataGridView so that I could look at two cells and draw
Here, you can try it yourself.
Graphics graphics = This.view.CreateGraphics ();
Draw the original text separately and now change the color of the text
Graphics. DrawString ("CCCC", this. Font, New SolidBrush (E.cellstyle.forecolor), Rectanle, Stringformat.genericdefault);
E.handled = true;
}
}
}
}

The following is my proposal, although this seems to solve the problem, in fact, there are many shortcomings, one is not editable, and this also has a bug is to click on the left side of the border will be left to hide the text, I tried a lot of methods are not resolved, this should be the background color to cover the editing.

I recommend a third-party control that can merge cells (Devexpress.xtragrid.v7.3.dll), which I do not study now, but I will study it later, I will write an article

DataGridView Merging Cells