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1 、 CellFormatting 事件，一般重绘单元格属性。
private Bitmap highPriImage; private Bitmap mediumPriImage; private Bitmap lowPriImage; private void dataGridView1_CellFormatting(object sender, System.Windows.Forms.DataGridViewCellFormattingEventArgs e) { // Set the background to red for negative values in the Balance column. if (dataGridView1.Columns[e.ColumnIndex].Name.Equals("Balance")) { Int32 intValue; if (Int32.TryParse((String)e.Value, out intValue) && (intValue < 0)) { e.CellStyle.BackColor = Color.Red; e.CellStyle.SelectionBackColor = Color.DarkRed; } } // Replace string values in the Priority column with images. if (dataGridView1.Columns[e.ColumnIndex].Name.Equals("Priority")) { // Ensure that the value is a string. String stringValue = e.Value as string; if (stringValue == null) return; // Set the cell ToolTip to the text value. DataGridViewCell cell = dataGridView1[e.ColumnIndex, e.RowIndex]; cell.ToolTipText = stringValue; // Replace the string value with the image value. switch (stringValue) { case "high": e.Value = highPriImage; break; case "medium": e.Value = mediumPriImage; break; case "low": e.Value = lowPriImage; break; } } } 2 、 CellPainting 事件，一般用于合并单元格用
Windows Forms DataGridView 没有提供合并单元格的功能，要实现合并单元格的功能就要在 CellPainting 事件中使用 Graphics.DrawLine 和 Graphics.DrawString 自己来 “ 画 ” 。
下面的代码可以对 DataGridView 第 1 列内容相同的单元格进行合并：
#region" 合并单元格的测试 " private int? nextrow = null; private int? nextcol = null; private void dataGridView1_CellFormatting(object sender, System.Windows.Forms.DataGridViewCellFormattingEventArgs e) { if (this.dataGridView1.Columns["description"].Index == e.ColumnIndex && e.RowIndex >= 0) { if (this.nextcol != null & e.ColumnIndex == this.nextcol) { e.CellStyle.BackColor = Color.LightBlue; this.nextcol = null; } if (this.nextrow != null & e.RowIndex == nextrow) { e.CellStyle.BackColor = Color.LightPink; this.nextrow = null; } if (e.RowIndex != this.dataGridView1.RowCount - 1) { if (e.Value.ToString() == this.dataGridView1.Rows[e.RowIndex + 1].Cells[e.ColumnIndex].Value.ToString()) { e.CellStyle.BackColor = Color.LightPink; nextrow = e.RowIndex + 1; } } }
if (this.dataGridView1.Columns["name"].Index == e.ColumnIndex && e.RowIndex >= 0)
{
if (e.Value.ToString() == this.dataGridView1.Rows[e.RowIndex].Cells[e.ColumnIndex + 1].Value.ToString())
{
e.CellStyle.BackColor = Color.LightBlue;
nextcol = e.ColumnIndex + 1;
}
}
}
//==========================
// 绘制单元格
private void dataGridView1_CellPainting(object sender, System.Windows.Forms.DataGridViewCellPaintingEventArgs e) { // 纵向合并
if (this.dataGridView1.Columns["description"].Index == e.ColumnIndex && e.RowIndex >= 0) { using (
Brush gridBrush = new SolidBrush(this.dataGridView1.GridColor),
backColorBrush = new SolidBrush(e.CellStyle.BackColor))
{
using (Pen gridLinePen = new Pen(gridBrush))
{
// 擦除原单元格背景
e.Graphics.FillRectangle(backColorBrush, e.CellBounds); 绘制线条 , 这些线条是单元格相互间隔的区分线条 ,
因为我们只对列 name 做处理 , 所以 datagridview 自己会处理左侧和上边缘的线条
if (e.RowIndex != this.dataGridView1.RowCount - 1) { if (e.Value.ToString() != this.dataGridView1.Rows[e.RowIndex + 1].Cells[e.ColumnIndex].Value.ToString()) { e.Graphics.DrawLine(gridLinePen, e.CellBounds.Left, e.CellBounds.Bottom - 1,
e.CellBounds.Right - 1, e.CellBounds.Bottom - 1);// 下边缘的线
// 绘制值
if (e.Value != null) { e.Graphics.DrawString((String)e.Value, e.CellStyle.Font, Brushes.Crimson, e.CellBounds.X + 2, e.CellBounds.Y + 2, StringFormat.GenericDefault); } } } else { e.Graphics.DrawLine(gridLinePen, e.CellBounds.Left, e.CellBounds.Bottom - 1, e.CellBounds.Right - 1, e.CellBounds.Bottom - 1);// 下边缘的线
// 绘制值
if (e.Value != null) { e.Graphics.DrawString((String)e.Value, e.CellStyle.Font, Brushes.Crimson, e.CellBounds.X + 2, e.CellBounds.Y + 2, StringFormat.GenericDefault); } } // 右侧的线
e.Graphics.DrawLine(gridLinePen, e.CellBounds.Right - 1, e.CellBounds.Top, e.CellBounds.Right - 1, e.CellBounds.Bottom - 1); // 横向合并
if (this.dataGridView1.Columns["name"].Index == e.ColumnIndex && e.RowIndex >= 0) { using (
Brush gridBrush = new SolidBrush(this.dataGridView1.GridColor),
backColorBrush = new SolidBrush(e.CellStyle.BackColor))
{
using (Pen gridLinePen = new Pen(gridBrush))
{
// 擦除原单元格背景
e.Graphics.FillRectangle(backColorBrush, e.CellBounds); if (e.Value.ToString() != this.dataGridView1.Rows[e.RowIndex].Cells[e.ColumnIndex + 1].Value.ToString()) { // 右侧的线
e.Graphics.DrawLine(gridLinePen, e.CellBounds.Right - 1, e.CellBounds.Top, e.CellBounds.Right - 1, e.CellBounds.Bottom - 1); // 绘制值
if (e.Value != null) { e.Graphics.DrawString((String)e.Value, e.CellStyle.Font, Brushes.Crimson, e.CellBounds.X + 2, e.CellBounds.Y + 2, StringFormat.GenericDefault); } } // 下边缘的线
e.Graphics.DrawLine(gridLinePen, e.CellBounds.Left, e.CellBounds.Bottom - 1, e.CellBounds.Right - 1, e.CellBounds.Bottom - 1); e.Handled = true; } } 本文转自 qianshao 51CTO博客，原文链接：http://blog.51cto.com/qianshao/201801，如需转载请自行联系原作者