# CancelProc Class

> A callback function used to abort an operation.

- Product: Adobe PDF Library 21
- Language: .NET Framework
- Version: APDFL21.0.0PlusP1e
- HTML page: https://docs.datalogics.com/apdfl21/DotNetFramework/APDFL21.0.0PlusP1e/class/CancelProc
- Version index: https://docs.datalogics.com/apdfl21/DotNetFramework/APDFL21.0.0PlusP1e/llms.txt

```csharp
class CancelProc : SystemIDisposable
```

**Namespace:** `Datalogics::PDFL`

**Inherits from:** `SystemIDisposable`

## Description

A callback function used to abort an operation.

A CancelProc() value is typically passed to a method that uses it to determine if an asynchronous operation should be ended.

At periodic intervals, the method calls the CancelProc. If the CancelProc returns a "true" boolean value, the method cancels the operation. If CancelProc returns false, the method allows the operation to continue. For example, CancelProc could be used to allow a user to click a Cancel button to end a function.

**Referenced by:** [`Document`](https://docs.datalogics.com/apdfl21/DotNetFramework/APDFL21.0.0PlusP1e/class/Document.md), [`DrawParams`](https://docs.datalogics.com/apdfl21/DotNetFramework/APDFL21.0.0PlusP1e/class/DrawParams.md), [`PDFOptimizer`](https://docs.datalogics.com/apdfl21/DotNetFramework/APDFL21.0.0PlusP1e/class/PDFOptimizer.md), [`SignDoc`](https://docs.datalogics.com/apdfl21/DotNetFramework/APDFL21.0.0PlusP1e/class/SignDoc.md)

## Constructors

### CancelProc

```csharp
Datalogics.PDFL.CancelProc.CancelProc()
```

*constructor*

A callback function used to abort an operation.

A CancelProc() value is typically passed to a method that uses it to determine if an asynchronous operation should be ended.

At periodic intervals, the method calls the CancelProc. If the CancelProc returns a "true" boolean value, the method cancels the operation. If CancelProc returns false, the method allows the operation to continue. For example, CancelProc could be used to allow a user to click a Cancel button to end a function.

## Methods

### Call

```csharp
virtual bool Datalogics.PDFL.CancelProc.Call()
```

**Returns:** `bool`

### Dispose

```csharp
void Datalogics.PDFL.CancelProc.Dispose()
```

**Returns:** `void`