我还需要有一个CheckBox在 a 的列标题中DataGridView柱子。我是这样做的：
- 创建一个继承自的类
DataGridViewColumnHeaderCell
- 内部使用一个
System.Windows.Forms.CheckBox存储检查状态并提供操作系统风格的视觉效果CheckBox表示。
- Use a
Bitmap作为缓冲区并绘制常规CheckBox在其上（使用CheckBox.DrawToBitmap)
- 覆盖
DataGridViewColumnHeaderCell.Paint并且，如有必要，在将缓冲区绘制到之前更新缓冲区Graphics受供于Paint
- 在派生上提供 Checked 属性
DataGridViewColumnHeaderCell，还有一个 CheckedChanged 事件
- 代入导出的
DataGridViewColumnHeaderCell在专栏的HeaderCell当。。。的时候DataGridView正在填充。
- 勾选和取消勾选
CheckBox当单击列标题时，仅当鼠标单击在范围内时CheckBox
- 通过监听派生类外部实现全选/取消全选
CheckedChanged事件，更新底层数据对象，然后调用ResetBindings更新DataGridView
这是我写的类，它派生自DataGridViewColumnHeaderCell:
class DataGridViewCheckBoxColumnHeaderCell : DataGridViewColumnHeaderCell
{
private Bitmap buffer;
private CheckBox checkBox;
private Rectangle checkBoxBounds;
public DataGridViewCheckBoxColumnHeaderCell()
{
this.checkBox = new CheckBox();
}
public event EventHandler CheckedChanged;
public bool Checked
{
get
{
return this.checkBox.Checked;
}
set
{
if (!this.Checked == value)
{
this.checkBox.Checked = value;
if (this.buffer != null)
{
this.buffer.Dispose();
this.buffer = null;
}
this.OnCheckedChanged(EventArgs.Empty);
if (this.DataGridView != null)
{
this.DataGridView.Refresh();
}
}
}
}
protected override void Paint(
Graphics graphics,
Rectangle clipBounds,
Rectangle cellBounds,
int rowIndex,
DataGridViewElementStates dataGridViewElementState,
object value,
object formattedValue,
string errorText,
DataGridViewCellStyle cellStyle,
DataGridViewAdvancedBorderStyle advancedBorderStyle,
DataGridViewPaintParts paintParts)
{
// Passing String.Empty in place of
// value and formattedValue prevents
// this header cell from having text.
base.Paint(
graphics,
clipBounds,
cellBounds,
rowIndex,
dataGridViewElementState,
String.Empty,
String.Empty,
errorText,
cellStyle,
advancedBorderStyle,
paintParts);
if (this.buffer == null
|| cellBounds.Width != this.buffer.Width
|| cellBounds.Height != this.buffer.Height)
{
this.UpdateBuffer(cellBounds.Size);
}
graphics.DrawImage(this.buffer, cellBounds.Location);
}
protected override Size GetPreferredSize(
Graphics graphics,
DataGridViewCellStyle cellStyle,
int rowIndex,
Size constraintSize)
{
return this.checkBox.GetPreferredSize(constraintSize);
}
protected override void OnMouseClick(DataGridViewCellMouseEventArgs e)
{
if (e.Button == MouseButtons.Left
&& this.checkBoxBounds.Contains(e.Location))
{
this.Checked = !this.Checked;
}
base.OnMouseClick(e);
}
private void UpdateBuffer(Size size)
{
Bitmap updatedBuffer = new Bitmap(size.Width, size.Height);
this.checkBox.Size = size;
if (this.checkBox.Size.Width > 0 && this.checkBox.Size.Height > 0)
{
Bitmap renderedCheckbox = new Bitmap(
this.checkBox.Width,
this.checkBox.Height);
this.checkBox.DrawToBitmap(
renderedCheckbox,
new Rectangle(new Point(), this.checkBox.Size));
MakeTransparent(renderedCheckbox, this.checkBox.BackColor);
Bitmap croppedRenderedCheckbox = AutoCrop(
renderedCheckbox,
Color.Transparent);
// TODO implement alignment, right now it is always
// MiddleCenter regardless of this.Style.Alignment
this.checkBox.Location = new Point(
(updatedBuffer.Width - croppedRenderedCheckbox.Width) / 2,
(updatedBuffer.Height - croppedRenderedCheckbox.Height) / 2);
Graphics updatedBufferGraphics = Graphics.FromImage(updatedBuffer);
updatedBufferGraphics.DrawImage(
croppedRenderedCheckbox,
this.checkBox.Location);
this.checkBoxBounds = new Rectangle(
this.checkBox.Location,
croppedRenderedCheckbox.Size);
renderedCheckbox.Dispose();
croppedRenderedCheckbox.Dispose();
}
if (this.buffer != null)
{
this.buffer.Dispose();
}
this.buffer = updatedBuffer;
}
protected virtual void OnCheckedChanged(EventArgs e)
{
EventHandler handler = this.CheckedChanged;
if (handler != null)
{
handler(this, e);
}
}
// The methods below are helper methods for manipulating Bitmaps
private static void MakeTransparent(Bitmap bitmap, Color transparencyMask)
{
int transparencyMaskArgb = transparencyMask.ToArgb();
int transparentArgb = Color.Transparent.ToArgb();
List deadColumns = new List();
for (int x = 0; x = 0; x--)
{
if (deadColumns.Count == bitmap.Height)
{
break;
}
for (int y = bitmap.Height - 1; y >= 0; y--)
{
if (deadColumns.Contains(y))
{
continue;
}
int pixel = bitmap.GetPixel(x, y).ToArgb();
if (pixel == transparencyMaskArgb)
{
bitmap.SetPixel(x, y, Color.Transparent);
}
else if (pixel != transparentArgb)
{
deadColumns.Add(y);
break;
}
}
}
}
public static Bitmap AutoCrop(Bitmap bitmap, Color backgroundColor)
{
Size croppedSize = bitmap.Size;
Point cropOrigin = new Point();
int backgroundColorToArgb = backgroundColor.ToArgb();
for (int x = bitmap.Width - 1; x >= 0; x--)
{
bool allPixelsAreBackgroundColor = true;
for (int y = bitmap.Height - 1; y >= 0; y--)
{
if (bitmap.GetPixel(x, y).ToArgb() != backgroundColorToArgb)
{
allPixelsAreBackgroundColor = false;
break;
}
}
if (allPixelsAreBackgroundColor)
{
croppedSize.Width--;
}
else
{
break;
}
}
for (int y = bitmap.Height - 1; y >= 0; y--)
{
bool allPixelsAreBackgroundColor = true;
for (int x = bitmap.Width - 1; x >= 0; x--)
{
if (bitmap.GetPixel(x, y).ToArgb() != backgroundColorToArgb)
{
allPixelsAreBackgroundColor = false;
break;
}
}
if (allPixelsAreBackgroundColor)
{
croppedSize.Height--;
}
else
{
break;
}
}
for (int x = 0; x = 0 && xWhole = 0)
{
bitmapSection.SetPixel(x, y, bitmap.GetPixel(xWhole, yWhole));
}
else
{
bitmapSection.SetPixel(x, y, Color.Transparent);
}
}
}
return bitmapSection;
}
}
