DataGridView列标题合并
DataGridView合并单元格，方法MergeHeader重绘单元格，响应DataGridView的CellPainting事件。
/// <summary>
/// 合并表头,用在dataGridView的CellPainting事件中。
/// </summary>
/// <param name="sender">需要重绘的dataGridview</param>
/// <param name="e">CellPainting中的参数</param>
///<param name="colName">列的集合(列必须是连续的，第一列放在最前面)</param>
/// <param name="headerText">列合并后显示的文本</param>
public void MergeHeader(object sender, DataGridViewCellPaintingEventArgs e, List<string> colNameCollection, string headerText)
{
if (e.RowIndex == -1)
{
DataGridView dg = sender as DataGridView;
if (e.ColumnIndex < 0)
{
return;
}
string colName = dg.Columns[e.ColumnIndex].Name;
if (!isEnLarged)
{
//0.扩展表头高度为当前的2倍
dg.ColumnHeadersHeightSizeMode = DataGridViewColumnHeadersHeightSizeMode.EnableResizing;
dg.ColumnHeadersHeight = e.CellBounds.Height * 2;
isEnLarged = true;
}
if (colNameCollection.Contains(colName))
{
#region 重绘列头
//1.计算colLen个列的区域
if (colNameCollection.IndexOf(colName) == 0)
{
cTop = e.CellBounds.Top;
cLeft = e.CellBounds.Left;
cWidth = e.CellBounds.Width;
cHeight = e.CellBounds.Height / 2;
foreach (string colNameItem in colNameCollection)
{
if (colNameItem.Equals(colName))
{//除去自己一个，加了之后colLen-1个列的宽
continue;
}
cWidth += dg.Columns[colNameItem].Width;
}
}
Rectangle cArea = new Rectangle(cLeft, cTop, cWidth, cHeight);
//2.把区域设置为背景色，没有列的分线及任何文字。
using (Brush backColorBrush = new SolidBrush(e.CellStyle.BackColor))
{
e.Graphics.FillRectangle(backColorBrush, cArea);
}
//3.绘制新列头的边框
using (Pen gridPen = new Pen(dg.GridColor))
{
//3.1 上部边框
e.Graphics.DrawLine(gridPen, cLeft, cTop, cLeft + cWidth, cTop);
using (Pen hilightPen = new Pen(Color.WhiteSmoke))
{
//3.2 顶部高光
e.Graphics.DrawLine(hilightPen, cLeft, cTop + 1, cLeft + cWidth, cTop + 1);
//3.3 左部反光线
e.Graphics.DrawLine(hilightPen, cLeft, cTop + 3, cLeft, cTop + cHeight - 2);
}
//3.4 下部边框
e.Graphics.DrawLine(gridPen, cLeft, cTop + cHeight - 1, cLeft + cWidth, cTop + cHeight - 1);
//3.5 右部边框
e.Graphics.DrawLine(gridPen, cLeft + cWidth - 1, cTop, cLeft + cWidth - 1, cTop + cHeight);//(cTop+cHeight)/2);
}
//4.写文本
//不是第一列则不写文字。
int wHeadStr = (int)(headerText.Length * e.CellStyle.Font.SizeInPoints);
int wHeadCell = (cWidth - wHeadStr) / 2;
int pHeadLeft = wHeadCell + cLeft;
using (Brush foreBrush = new SolidBrush(e.CellStyle.ForeColor))
{
e.Graphics.DrawString(headerText, e.CellStyle.Font, foreBrush, new PointF(pHeadLeft, cTop + 3));
}
//5 绘制子列背景
int FatherColHeight = e.CellBounds.Height / 2;//上面一行的高度
using (Brush backColorBrush = new SolidBrush(e.CellStyle.BackColor))
{
e.Graphics.FillRectangle(backColorBrush, new Rectangle(e.CellBounds.X, e.CellBounds.Y + FatherColHeight, e.CellBounds.Width - 1, e.CellBounds.Height / 2 - 1));
}
//5.1绘制子列的边框
using (Pen gridPen = new Pen(dg.GridColor))
{
using (Pen hilightPen = new Pen(Color.WhiteSmoke))
{
//5.2 左部反光线
e.Graphics.DrawLine(hilightPen, cLeft, cTop + 3 + FatherColHeight, cLeft, cTop + cHeight - 2 + FatherColHeight);
}
//5.3 下部边框
e.Graphics.DrawLine(gridPen, cLeft, cTop + cHeight - 1 + FatherColHeight, cLeft + cWidth, cTop + cHeight - 1 + FatherColHeight);
//5.4 右部边框
e.Graphics.DrawLine(gridPen, e.CellBounds.X + e.CellBounds.Width - 1, e.CellBounds.Top + FatherColHeight, e.CellBounds.X + e.CellBounds.Width - 1, e.CellBounds.Top + e.CellBounds.Height + FatherColHeight);//(cTop+cHeight)/2);
}
//5.5 写子列的文本
int wStr = (int)(dg.Columns[e.ColumnIndex].HeaderText.Length * e.CellStyle.Font.SizeInPoints);
int wCell = e.CellBounds.Width;
int pLeft = (wCell - wStr) / 2;//相对CELL左边框的左坐标
using (Brush foreBrush = new SolidBrush(e.CellStyle.ForeColor))
{
e.Graphics.DrawString(dg.Columns[e.ColumnIndex].HeaderText, e.CellStyle.Font, foreBrush, new PointF(e.CellBounds.X + pLeft, cTop+5 + FatherColHeight));
}
#endregion
e.Handled = true;
}
}
}