推荐订阅源

For all those getting the error:

"Unable to cast object of type 'System.Windows.Forms.DataGridViewTextBoxCell' to type 'AdvancedDataGridView.TreeGridCell'."

If you legitimately want to have a textbox column in front of the TreeGridColumn make the following change.

In TreeGridNode.cs at line 262 (Or find the following statement:

<---

if (cell.GetType().IsAssignableFrom(typeof(TreeGridCell)))

<---

Replace it with this if statement:

<---

if (cell.GetType().Equals(typeof(TreeGridCell)))

<---

The problem is the TreeGridColumn was inherited from the texBoxColumn so the original statement was giving a false positve.

Hope it helps.

Dear Mark,

thanks for sharing this. As others pointed out already, expanding nodes becomes utterly slow even for just a few hundred nodes.

The problem lies in changing the CellStyle Padding in TreeGridCell.cs line 106.

Changing this seems to rebuild the geometry of the entire tree. But the Padding is not used in the base code but only in the overridden Paint method.

Thus an easy solution to speed up this widget is to introduce your own Padding field. This works fine as the vertical padding keeps constant and thus changes do not affect other cells.

Best Regards

Matthias

Hi Mark,

Thank you for this great control. As far as the slow performance caused by setting the Padding goes (thanks for identifing the problem Matthias!), one easy solution is to calculate the padding inside OnPaint().

This is what I did roughly:

TreeGridCell.cs in function OnPaint():

replaced

Rectangle glyphRect = new Rectangle(cellBounds.X + this.GlyphMargin, cellBounds.Y, INDENT_WIDTH, cellBounds.Height - 1);

with

_lastKnownGlyphRect = new Rectangle(cellBounds.X + this.GlyphMargin, cellBounds.Y, INDENT_WIDTH, cellBounds.Height - 1);

and moved the call just before base.OnPaint().

Added

cellStyle.Padding = new Padding(_lastKnownGlyphRect.Right+_imageWidth, 0, 0, 0);

just before calling base.OnPaint().

Naturally, I hashed out setting this.Style.Padding at the end of UpdateStyle(). And I had to change OnMouseDown() and replace

if (e.Location.X > this.InheritedStyle.Padding.Left)

with

if (e.Location.X > _lastKnownGlyphRect.Right || e.Location.X < _lastKnownGlyphRect.Left)

Works much faster with larger number of elements now. :) Just be careful when using my code, I haven't tested it thoroughly yet. :P