# OpcPathProbing Class

> Reference: Provides an abstract base class which defines mechanisms to evaluate string-based path values used to access the file system.

<span class="api-meta">abstract · since v2.7</span>

<dl class="api-definition">
<dt>Namespace</dt>
<dd><a href="../namespaces/opc.uafx">Opc.UaFx</a></dd>
<dt>Assembly</dt>
<dd>Opc.UaFx.Advanced.dll</dd>
<dt>Package</dt>
<dd>Opc.UaFx.Advanced v2.59.0</dd>
<dt>Members</dt>
<dd><a href="./members">OpcPathProbing Members</a></dd>
<dt>Also in</dt>
<dd>Opc.UaFx.Client</dd>
</dl>

Provides an abstract base class which defines mechanisms to evaluate [string](https://learn.microsoft.com/dotnet/api/system.string)-based path values used to access the file system. A path probing evaluates a specific path (source) against its existence, its acessibility and other circumstances and offers only successful evaluated path information.

## Syntax

<div class="api-signature" data-lang="csharp">

```csharp
public abstract class OpcPathProbing
```

</div>

<div class="api-signature" data-lang="vbnet">

```vbnet
Public MustInherit Class OpcPathProbing
```

</div>

## Inheritance

[Object](https://learn.microsoft.com/dotnet/api/system.object) → **OpcPathProbing**

## Derived types

- [OpcDirectoryPathProbing](https://www.traeger.de/en/docs/development/opcua/api/v2.59/opc.uafx.opcdirectorypathprobing/)
- [OpcSpecialFolderPathProbing](https://www.traeger.de/en/docs/development/opcua/api/v2.59/opc.uafx.opcspecialfolderpathprobing/)

## Constructors

| Name | Description |
|---|---|
| [OpcPathProbing](https://www.traeger.de/en/docs/development/opcua/api/v2.59/opc.uafx.opcpathprobing/members#opcpathprobing)<span class="api-meta">protected</span> | Initializes a new instance of the OpcPathProbing class. |

## Methods

| Name | Description |
|---|---|
| [Evaluate](https://www.traeger.de/en/docs/development/opcua/api/v2.59/opc.uafx.opcpathprobing/members#evaluate) | Processes the evaluation of the [string](https://learn.microsoft.com/dotnet/api/system.string)-based path value associated with this OpcPathProbing and offers the determined and fulfilled path information accordingly. |
| [EvaluateCore](https://www.traeger.de/en/docs/development/opcua/api/v2.59/opc.uafx.opcpathprobing/members#evaluatecore)<span class="api-meta">protected · abstract</span> | When implemented in a derived class, processes the implementation specific evaluation of the [string](https://learn.microsoft.com/dotnet/api/system.string)-based path value associated with this OpcPathProbing specialization and offers the determined and fulfilled path information accordingly. |
| [OnFailed](https://www.traeger.de/en/docs/development/opcua/api/v2.59/opc.uafx.opcpathprobing/members#onfailed)<span class="api-meta">protected · virtual</span> | Raises the [Failed](https://www.traeger.de/en/docs/development/opcua/api/v2.59/opc.uafx.opcpathprobing/members#failed) event of the OpcPathProbing. |
| [ReportFailed](https://www.traeger.de/en/docs/development/opcua/api/v2.59/opc.uafx.opcpathprobing/members#reportfailed)<span class="api-meta">protected · 3 overloads</span> | Reports the failure of the evaluation using the `exception` which led to the nonsuccess. |

## Events

| Name | Description |
|---|---|
| [Failed](https://www.traeger.de/en/docs/development/opcua/api/v2.59/opc.uafx.opcpathprobing/members#failed) | Occurs when a call to [Evaluate](https://www.traeger.de/en/docs/development/opcua/api/v2.59/opc.uafx.opcpathprobing/members#evaluate) failed upon a specific reason. |

## Applies to

| Package | Versions |
|---|---|
| Opc.UaFx.Advanced | v2.7–v2.59 |