---
title: "Bitmap..::.ClearUndoHistory Method "
canonical: https://www.graphicsmill.com/docs/gm5/M_Aurigma_GraphicsMill_Bitmap_ClearUndoHistory.htm
product: "Graphics Mill 5.5 for .NET"
---

This documentation is for the old version. [Go to the latest Graphics Mill docs](https://www.graphicsmill.com/docs/gm/)

# Bitmap.ClearUndoHistory Method 
 
Discards undo history.
 
**Namespace:** [Aurigma.GraphicsMill](https://www.graphicsmill.com/docs/gm5/N_Aurigma_GraphicsMill.htm.md)
 **Assembly:** Aurigma.GraphicsMill (in Aurigma.GraphicsMill.dll)
 
## Syntax
  
```
Public Overridable Sub ClearUndoHistory
```
 
```csharp
public virtual void ClearUndoHistory()
```
 
### Implements
 
[IStateNavigable.ClearUndoHistory()](https://www.graphicsmill.com/docs/gm5/M_Aurigma_GraphicsMill_IStateNavigable_ClearUndoHistory.htm.md)
 
## Remarks
  
This method removes all temporary files which keep undo history. Redo history is not removed.
   
## See Also

### Reference

- [Bitmap Class](https://www.graphicsmill.com/docs/gm5/T_Aurigma_GraphicsMill_Bitmap.htm.md)
- [Aurigma.GraphicsMill Namespace](https://www.graphicsmill.com/docs/gm5/N_Aurigma_GraphicsMill.htm.md)
- [Bitmap.ClearHistory()](https://www.graphicsmill.com/docs/gm5/M_Aurigma_GraphicsMill_Bitmap_ClearHistory.htm.md)
- [Bitmap.ClearRedoHistory()](https://www.graphicsmill.com/docs/gm5/M_Aurigma_GraphicsMill_Bitmap_ClearRedoHistory.htm.md)