# OpcClient.ReadNodes Method

> Reference: Reads the Value attribute of the nodes specified by nodeIds.

<dl class="api-definition">
<dt>Type</dt>
<dd><a href="./">OpcClient</a></dd>
<dt>Namespace</dt>
<dd><a href="../namespaces/opc.uafx.client">Opc.UaFx.Client</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">OpcClient Members</a></dd>
<dt>Also in</dt>
<dd>Opc.UaFx.Client</dd>
</dl>

<span class="api-meta">10 overloads</span>

| Overload | Description |
|---|---|
| [ReadNodes(IEnumerable&lt;OpcNodeId&gt;)](https://www.traeger.de/en/docs/development/opcua/api/v2.59/opc.uafx.client.opcclient/readnodes#readnodes-system-collections-generic-ienumerable-of-opc-uafx-opcnodeid) | Reads the [Value](https://www.traeger.de/en/docs/development/opcua/api/v2.59/opc.uafx.opcattribute/#value) attribute of the nodes specified by `nodeIds`. |
| [ReadNodes(params OpcNodeId\[\])](#readnodes-opc-uafx-opcnodeid-array) | Reads the [Value](https://www.traeger.de/en/docs/development/opcua/api/v2.59/opc.uafx.opcattribute/#value) attribute of the nodes specified by `nodeIds`. |
| [ReadNodes(OpcAttribute, IEnumerable&lt;OpcNodeId&gt;)](https://www.traeger.de/en/docs/development/opcua/api/v2.59/opc.uafx.client.opcclient/readnodes#readnodes-opc-uafx-opcattribute-system-collections-generic-ienumerable-of-opc-uafx-opcnodeid) | Reads the `attribute` of the nodes specified by `nodeIds`. |
| [ReadNodes(OpcAttribute, params OpcNodeId\[\])](#readnodes-opc-uafx-opcattribute-opc-uafx-opcnodeid-array) | Reads the `attribute` of the nodes specified by `nodeIds`. |
| [ReadNodes(OpcRange, IEnumerable&lt;OpcNodeId&gt;)](https://www.traeger.de/en/docs/development/opcua/api/v2.59/opc.uafx.client.opcclient/readnodes#readnodes-opc-uafx-opcrange-system-collections-generic-ienumerable-of-opc-uafx-opcnodeid)<span class="api-meta">since v2.24</span> | Reads the `range` from the [Value](https://www.traeger.de/en/docs/development/opcua/api/v2.59/opc.uafx.opcattribute/#value) attribute of the nodes specified by `nodeIds`. |
| [ReadNodes(OpcRange, params OpcNodeId\[\])](#readnodes-opc-uafx-opcrange-opc-uafx-opcnodeid-array)<span class="api-meta">since v2.24</span> | Reads the `range` from the [Value](https://www.traeger.de/en/docs/development/opcua/api/v2.59/opc.uafx.opcattribute/#value) attribute of the nodes specified by `nodeIds`. |
| [ReadNodes(OpcAttribute, OpcRange, IEnumerable&lt;OpcNodeId&gt;)](https://www.traeger.de/en/docs/development/opcua/api/v2.59/opc.uafx.client.opcclient/readnodes#readnodes-opc-uafx-opcattribute-opc-uafx-opcrange-system-collections-generic-ienumerable-of-opc-uafx-opcnodeid)<span class="api-meta">since v2.24</span> | Reads the `range` from the `attribute` of the nodes specified by `nodeIds`. |
| [ReadNodes(OpcAttribute, OpcRange, params OpcNodeId\[\])](#readnodes-opc-uafx-opcattribute-opc-uafx-opcrange-opc-uafx-opcnodeid-array)<span class="api-meta">since v2.24</span> | Reads the `range` from the `attribute` of the nodes specified by `nodeIds`. |
| [ReadNodes(IEnumerable&lt;OpcReadNode&gt;)](https://www.traeger.de/en/docs/development/opcua/api/v2.59/opc.uafx.client.opcclient/readnodes#readnodes-system-collections-generic-ienumerable-of-opc-uafx-opcreadnode) | Reads one or more values of one or more attributes of one or more nodes using the specified `commands`. |
| [ReadNodes(params OpcReadNode\[\])](#readnodes-opc-uafx-opcreadnode-array) | Reads one or more values of one or more attributes of one or more nodes using the specified `commands`. |

**Known results:** [BadNodeIdInvalid](https://www.traeger.de/en/docs/development/opcua/api/v2.59/opc.uafx.opcstatuscode/#badnodeidinvalid), [BadNodeIdUnknown](https://www.traeger.de/en/docs/development/opcua/api/v2.59/opc.uafx.opcstatuscode/#badnodeidunknown), [BadAttributeInvalid](https://www.traeger.de/en/docs/development/opcua/api/v2.59/opc.uafx.opcstatuscode/#badattributeinvalid), [BadIndexRangeInvalid](https://www.traeger.de/en/docs/development/opcua/api/v2.59/opc.uafx.opcstatuscode/#badindexrangeinvalid), [BadIndexRangeNoData](https://www.traeger.de/en/docs/development/opcua/api/v2.59/opc.uafx.opcstatuscode/#badindexrangenodata), [BadDataEncodingInvalid](https://www.traeger.de/en/docs/development/opcua/api/v2.59/opc.uafx.opcstatuscode/#baddataencodinginvalid), [BadDataEncodingUnsupported](https://www.traeger.de/en/docs/development/opcua/api/v2.59/opc.uafx.opcstatuscode/#baddataencodingunsupported), [BadNotReadable](https://www.traeger.de/en/docs/development/opcua/api/v2.59/opc.uafx.opcstatuscode/#badnotreadable), [BadUserAccessDenied](https://www.traeger.de/en/docs/development/opcua/api/v2.59/opc.uafx.opcstatuscode/#baduseraccessdenied)

**Exceptions (all overloads)**

| Exception | Condition |
|---|---|
| [ObjectDisposedException](https://learn.microsoft.com/dotnet/api/system.objectdisposedexception) | The object has been disposed of. |
| [OpcException](https://www.traeger.de/en/docs/development/opcua/api/v2.59/opc.uafx.opcexception/) | The service execution failed upon different circumstances; for more details see exception details. The following issues can lead to that exception: [BadNothingToDo](https://www.traeger.de/en/docs/development/opcua/api/v2.59/opc.uafx.opcstatuscode/#badnothingtodo), [BadTooManyOperations](https://www.traeger.de/en/docs/development/opcua/api/v2.59/opc.uafx.opcstatuscode/#badtoomanyoperations), [BadMaxAgeInvalid](https://www.traeger.de/en/docs/development/opcua/api/v2.59/opc.uafx.opcstatuscode/#badmaxageinvalid) and [BadTimestampsToReturnInvalid](https://www.traeger.de/en/docs/development/opcua/api/v2.59/opc.uafx.opcstatuscode/#badtimestampstoreturninvalid). |

## ReadNodes(IEnumerable&lt;OpcNodeId&gt;)

Reads the [Value](https://www.traeger.de/en/docs/development/opcua/api/v2.59/opc.uafx.opcattribute/#value) attribute of the nodes specified by `nodeIds`.

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

```csharp
public IEnumerable<OpcValue> ReadNodes(IEnumerable<OpcNodeId> nodeIds)
```

</div>

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

```vbnet
Public Function ReadNodes(
    nodeIds As IEnumerable(Of OpcNodeId)) As IEnumerable(Of OpcValue)
```

</div>

**Parameters**

| Name | Type | Description |
|---|---|---|
| `nodeIds` | [IEnumerable](https://learn.microsoft.com/dotnet/api/system.collections.generic.ienumerable-1)&lt;[OpcNodeId](https://www.traeger.de/en/docs/development/opcua/api/v2.59/opc.uafx.opcnodeid/)&gt; | A sequence of [OpcNodeId](https://www.traeger.de/en/docs/development/opcua/api/v2.59/opc.uafx.opcnodeid/) instances of the nodes to read. |

**Returns**

[IEnumerable](https://learn.microsoft.com/dotnet/api/system.collections.generic.ienumerable-1)&lt;[OpcValue](https://www.traeger.de/en/docs/development/opcua/api/v2.59/opc.uafx.opcvalue/)&gt;

A sequence of [OpcValue](https://www.traeger.de/en/docs/development/opcua/api/v2.59/opc.uafx.opcvalue/) instances its number and order of items matches the number and order of items in the `nodeIds` sequence. There is for each node identifier one entry which stores the value requested.

**Exceptions**

| Exception | Condition |
|---|---|
| [ArgumentNullException](https://learn.microsoft.com/dotnet/api/system.argumentnullexception) | The `nodeIds` sequence or one of its items is a null reference (Nothing in Visual Basic). |
| [InvalidOperationException](https://learn.microsoft.com/dotnet/api/system.invalidoperationexception) | The read service is currently not supported, especially using the `nodeIds` specified. |

## ReadNodes(params OpcNodeId\[\])

Reads the [Value](https://www.traeger.de/en/docs/development/opcua/api/v2.59/opc.uafx.opcattribute/#value) attribute of the nodes specified by `nodeIds`.

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

```csharp
public IEnumerable<OpcValue> ReadNodes(params OpcNodeId[] nodeIds)
```

</div>

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

```vbnet
Public Function ReadNodes(
    ParamArray nodeIds As OpcNodeId()) As IEnumerable(Of OpcValue)
```

</div>

**Parameters**

| Name | Type | Description |
|---|---|---|
| `nodeIds` | params [OpcNodeId](https://www.traeger.de/en/docs/development/opcua/api/v2.59/opc.uafx.opcnodeid/)[] | An array of [OpcNodeId](https://www.traeger.de/en/docs/development/opcua/api/v2.59/opc.uafx.opcnodeid/) instances of the nodes to read. |

**Returns**

[IEnumerable](https://learn.microsoft.com/dotnet/api/system.collections.generic.ienumerable-1)&lt;[OpcValue](https://www.traeger.de/en/docs/development/opcua/api/v2.59/opc.uafx.opcvalue/)&gt;

A sequence of [OpcValue](https://www.traeger.de/en/docs/development/opcua/api/v2.59/opc.uafx.opcvalue/) instances its number and order of items matches the number and order of items in the `nodeIds` sequence. There is for each node identifier one entry which stores the value requested.

**Exceptions**

| Exception | Condition |
|---|---|
| [ArgumentNullException](https://learn.microsoft.com/dotnet/api/system.argumentnullexception) | The `nodeIds` sequence or one of its items is a null reference (Nothing in Visual Basic). |
| [InvalidOperationException](https://learn.microsoft.com/dotnet/api/system.invalidoperationexception) | The read service is currently not supported, especially using the `nodeIds` specified. |

## ReadNodes(OpcAttribute, IEnumerable&lt;OpcNodeId&gt;)

Reads the `attribute` of the nodes specified by `nodeIds`.

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

```csharp
public IEnumerable<OpcValue> ReadNodes(
    OpcAttribute attribute,
    IEnumerable<OpcNodeId> nodeIds)
```

</div>

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

```vbnet
Public Function ReadNodes(
    attribute As OpcAttribute,
    nodeIds As IEnumerable(Of OpcNodeId)) As IEnumerable(Of OpcValue)
```

</div>

**Parameters**

| Name | Type | Description |
|---|---|---|
| `attribute` | [OpcAttribute](https://www.traeger.de/en/docs/development/opcua/api/v2.59/opc.uafx.opcattribute/) | One of the members defined by the [OpcAttribute](https://www.traeger.de/en/docs/development/opcua/api/v2.59/opc.uafx.opcattribute/) enumeration that defines which node attribute is to be used by the service. |
| `nodeIds` | [IEnumerable](https://learn.microsoft.com/dotnet/api/system.collections.generic.ienumerable-1)&lt;[OpcNodeId](https://www.traeger.de/en/docs/development/opcua/api/v2.59/opc.uafx.opcnodeid/)&gt; | A sequence of [OpcNodeId](https://www.traeger.de/en/docs/development/opcua/api/v2.59/opc.uafx.opcnodeid/) instances of the nodes to read. |

**Returns**

[IEnumerable](https://learn.microsoft.com/dotnet/api/system.collections.generic.ienumerable-1)&lt;[OpcValue](https://www.traeger.de/en/docs/development/opcua/api/v2.59/opc.uafx.opcvalue/)&gt;

A sequence of [OpcValue](https://www.traeger.de/en/docs/development/opcua/api/v2.59/opc.uafx.opcvalue/) instances its number and order of items matches the number and order of items in the `nodeIds` sequence. There is for each node identifier one entry which stores the value requested.

**Exceptions**

| Exception | Condition |
|---|---|
| [ArgumentNullException](https://learn.microsoft.com/dotnet/api/system.argumentnullexception) | The `nodeIds` sequence or one of its items is a null reference (Nothing in Visual Basic). |
| [InvalidOperationException](https://learn.microsoft.com/dotnet/api/system.invalidoperationexception) | The read service is currently not supported, especially using the `nodeIds` specified. |

## ReadNodes(OpcAttribute, params OpcNodeId\[\])

Reads the `attribute` of the nodes specified by `nodeIds`.

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

```csharp
public IEnumerable<OpcValue> ReadNodes(
    OpcAttribute attribute,
    params OpcNodeId[] nodeIds)
```

</div>

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

```vbnet
Public Function ReadNodes(
    attribute As OpcAttribute,
    ParamArray nodeIds As OpcNodeId()) As IEnumerable(Of OpcValue)
```

</div>

**Parameters**

| Name | Type | Description |
|---|---|---|
| `attribute` | [OpcAttribute](https://www.traeger.de/en/docs/development/opcua/api/v2.59/opc.uafx.opcattribute/) | One of the members defined by the [OpcAttribute](https://www.traeger.de/en/docs/development/opcua/api/v2.59/opc.uafx.opcattribute/) enumeration that defines which node attribute is to be used by the service. |
| `nodeIds` | params [OpcNodeId](https://www.traeger.de/en/docs/development/opcua/api/v2.59/opc.uafx.opcnodeid/)[] | An array of [OpcNodeId](https://www.traeger.de/en/docs/development/opcua/api/v2.59/opc.uafx.opcnodeid/) instances of the nodes to read. |

**Returns**

[IEnumerable](https://learn.microsoft.com/dotnet/api/system.collections.generic.ienumerable-1)&lt;[OpcValue](https://www.traeger.de/en/docs/development/opcua/api/v2.59/opc.uafx.opcvalue/)&gt;

A sequence of [OpcValue](https://www.traeger.de/en/docs/development/opcua/api/v2.59/opc.uafx.opcvalue/) instances its number and order of items matches the number and order of items in the `nodeIds` sequence. There is for each node identifier one entry which stores the value requested.

**Exceptions**

| Exception | Condition |
|---|---|
| [ArgumentNullException](https://learn.microsoft.com/dotnet/api/system.argumentnullexception) | The `nodeIds` sequence or one of its items is a null reference (Nothing in Visual Basic). |
| [InvalidOperationException](https://learn.microsoft.com/dotnet/api/system.invalidoperationexception) | The read service is currently not supported, especially using the `nodeIds` specified. |

## ReadNodes(OpcRange, IEnumerable&lt;OpcNodeId&gt;)

<span class="api-meta">since v2.24</span>

Reads the `range` from the [Value](https://www.traeger.de/en/docs/development/opcua/api/v2.59/opc.uafx.opcattribute/#value) attribute of the nodes specified by `nodeIds`.

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

```csharp
public IEnumerable<OpcValue> ReadNodes(
    OpcRange range,
    IEnumerable<OpcNodeId> nodeIds)
```

</div>

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

```vbnet
Public Function ReadNodes(
    range As OpcRange,
    nodeIds As IEnumerable(Of OpcNodeId)) As IEnumerable(Of OpcValue)
```

</div>

**Parameters**

| Name | Type | Description |
|---|---|---|
| `range` | [OpcRange](https://www.traeger.de/en/docs/development/opcua/api/v2.59/opc.uafx.opcrange/) | The [OpcRange](https://www.traeger.de/en/docs/development/opcua/api/v2.59/opc.uafx.opcrange/) to use to identify the single element or range of elements to read. |
| `nodeIds` | [IEnumerable](https://learn.microsoft.com/dotnet/api/system.collections.generic.ienumerable-1)&lt;[OpcNodeId](https://www.traeger.de/en/docs/development/opcua/api/v2.59/opc.uafx.opcnodeid/)&gt; | A sequence of [OpcNodeId](https://www.traeger.de/en/docs/development/opcua/api/v2.59/opc.uafx.opcnodeid/) instances of the nodes to read. |

**Returns**

[IEnumerable](https://learn.microsoft.com/dotnet/api/system.collections.generic.ienumerable-1)&lt;[OpcValue](https://www.traeger.de/en/docs/development/opcua/api/v2.59/opc.uafx.opcvalue/)&gt;

A sequence of [OpcValue](https://www.traeger.de/en/docs/development/opcua/api/v2.59/opc.uafx.opcvalue/) instances its number and order of items matches the number and order of items in the `nodeIds` sequence. There is for each node identifier one entry which stores the value requested.

**Exceptions**

| Exception | Condition |
|---|---|
| [ArgumentNullException](https://learn.microsoft.com/dotnet/api/system.argumentnullexception) | The `nodeIds` sequence or one of its items is a null reference (Nothing in Visual Basic). |
| [InvalidOperationException](https://learn.microsoft.com/dotnet/api/system.invalidoperationexception) | The read service is currently not supported, especially using the `nodeIds` specified. |

## ReadNodes(OpcRange, params OpcNodeId\[\])

<span class="api-meta">since v2.24</span>

Reads the `range` from the [Value](https://www.traeger.de/en/docs/development/opcua/api/v2.59/opc.uafx.opcattribute/#value) attribute of the nodes specified by `nodeIds`.

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

```csharp
public IEnumerable<OpcValue> ReadNodes(
    OpcRange range,
    params OpcNodeId[] nodeIds)
```

</div>

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

```vbnet
Public Function ReadNodes(
    range As OpcRange,
    ParamArray nodeIds As OpcNodeId()) As IEnumerable(Of OpcValue)
```

</div>

**Parameters**

| Name | Type | Description |
|---|---|---|
| `range` | [OpcRange](https://www.traeger.de/en/docs/development/opcua/api/v2.59/opc.uafx.opcrange/) | The [OpcRange](https://www.traeger.de/en/docs/development/opcua/api/v2.59/opc.uafx.opcrange/) to use to identify the single element or range of elements to read. |
| `nodeIds` | params [OpcNodeId](https://www.traeger.de/en/docs/development/opcua/api/v2.59/opc.uafx.opcnodeid/)[] | An array of [OpcNodeId](https://www.traeger.de/en/docs/development/opcua/api/v2.59/opc.uafx.opcnodeid/) instances of the nodes to read. |

**Returns**

[IEnumerable](https://learn.microsoft.com/dotnet/api/system.collections.generic.ienumerable-1)&lt;[OpcValue](https://www.traeger.de/en/docs/development/opcua/api/v2.59/opc.uafx.opcvalue/)&gt;

A sequence of [OpcValue](https://www.traeger.de/en/docs/development/opcua/api/v2.59/opc.uafx.opcvalue/) instances its number and order of items matches the number and order of items in the `nodeIds` sequence. There is for each node identifier one entry which stores the value requested.

**Exceptions**

| Exception | Condition |
|---|---|
| [ArgumentNullException](https://learn.microsoft.com/dotnet/api/system.argumentnullexception) | The `nodeIds` sequence or one of its items is a null reference (Nothing in Visual Basic). |
| [InvalidOperationException](https://learn.microsoft.com/dotnet/api/system.invalidoperationexception) | The read service is currently not supported, especially using the `nodeIds` specified. |

## ReadNodes(OpcAttribute, OpcRange, IEnumerable&lt;OpcNodeId&gt;)

<span class="api-meta">since v2.24</span>

Reads the `range` from the `attribute` of the nodes specified by `nodeIds`.

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

```csharp
public IEnumerable<OpcValue> ReadNodes(
    OpcAttribute attribute,
    OpcRange range,
    IEnumerable<OpcNodeId> nodeIds)
```

</div>

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

```vbnet
Public Function ReadNodes(
    attribute As OpcAttribute,
    range As OpcRange,
    nodeIds As IEnumerable(Of OpcNodeId)) As IEnumerable(Of OpcValue)
```

</div>

**Parameters**

| Name | Type | Description |
|---|---|---|
| `attribute` | [OpcAttribute](https://www.traeger.de/en/docs/development/opcua/api/v2.59/opc.uafx.opcattribute/) | One of the members defined by the [OpcAttribute](https://www.traeger.de/en/docs/development/opcua/api/v2.59/opc.uafx.opcattribute/) enumeration that defines which node attribute is to be used by the service. |
| `range` | [OpcRange](https://www.traeger.de/en/docs/development/opcua/api/v2.59/opc.uafx.opcrange/) | The [OpcRange](https://www.traeger.de/en/docs/development/opcua/api/v2.59/opc.uafx.opcrange/) to use to identify the single element or range of elements to read. |
| `nodeIds` | [IEnumerable](https://learn.microsoft.com/dotnet/api/system.collections.generic.ienumerable-1)&lt;[OpcNodeId](https://www.traeger.de/en/docs/development/opcua/api/v2.59/opc.uafx.opcnodeid/)&gt; | A sequence of [OpcNodeId](https://www.traeger.de/en/docs/development/opcua/api/v2.59/opc.uafx.opcnodeid/) instances of the nodes to read. |

**Returns**

[IEnumerable](https://learn.microsoft.com/dotnet/api/system.collections.generic.ienumerable-1)&lt;[OpcValue](https://www.traeger.de/en/docs/development/opcua/api/v2.59/opc.uafx.opcvalue/)&gt;

A sequence of [OpcValue](https://www.traeger.de/en/docs/development/opcua/api/v2.59/opc.uafx.opcvalue/) instances its number and order of items matches the number and order of items in the `nodeIds` sequence. There is for each node identifier one entry which stores the value requested.

**Exceptions**

| Exception | Condition |
|---|---|
| [ArgumentNullException](https://learn.microsoft.com/dotnet/api/system.argumentnullexception) | The `nodeIds` sequence or one of its items is a null reference (Nothing in Visual Basic). |
| [InvalidOperationException](https://learn.microsoft.com/dotnet/api/system.invalidoperationexception) | The read service is currently not supported, especially using the `nodeIds` specified. |

## ReadNodes(OpcAttribute, OpcRange, params OpcNodeId\[\])

<span class="api-meta">since v2.24</span>

Reads the `range` from the `attribute` of the nodes specified by `nodeIds`.

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

```csharp
public IEnumerable<OpcValue> ReadNodes(
    OpcAttribute attribute,
    OpcRange range,
    params OpcNodeId[] nodeIds)
```

</div>

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

```vbnet
Public Function ReadNodes(
    attribute As OpcAttribute,
    range As OpcRange,
    ParamArray nodeIds As OpcNodeId()) As IEnumerable(Of OpcValue)
```

</div>

**Parameters**

| Name | Type | Description |
|---|---|---|
| `attribute` | [OpcAttribute](https://www.traeger.de/en/docs/development/opcua/api/v2.59/opc.uafx.opcattribute/) | One of the members defined by the [OpcAttribute](https://www.traeger.de/en/docs/development/opcua/api/v2.59/opc.uafx.opcattribute/) enumeration that defines which node attribute is to be used by the service. |
| `range` | [OpcRange](https://www.traeger.de/en/docs/development/opcua/api/v2.59/opc.uafx.opcrange/) | The [OpcRange](https://www.traeger.de/en/docs/development/opcua/api/v2.59/opc.uafx.opcrange/) to use to identify the single element or range of elements to read. |
| `nodeIds` | params [OpcNodeId](https://www.traeger.de/en/docs/development/opcua/api/v2.59/opc.uafx.opcnodeid/)[] | An array of [OpcNodeId](https://www.traeger.de/en/docs/development/opcua/api/v2.59/opc.uafx.opcnodeid/) instances of the nodes to read. |

**Returns**

[IEnumerable](https://learn.microsoft.com/dotnet/api/system.collections.generic.ienumerable-1)&lt;[OpcValue](https://www.traeger.de/en/docs/development/opcua/api/v2.59/opc.uafx.opcvalue/)&gt;

A sequence of [OpcValue](https://www.traeger.de/en/docs/development/opcua/api/v2.59/opc.uafx.opcvalue/) instances its number and order of items matches the number and order of items in the `nodeIds` sequence. There is for each node identifier one entry which stores the value requested.

**Exceptions**

| Exception | Condition |
|---|---|
| [ArgumentNullException](https://learn.microsoft.com/dotnet/api/system.argumentnullexception) | The `nodeIds` sequence or one of its items is a null reference (Nothing in Visual Basic). |
| [InvalidOperationException](https://learn.microsoft.com/dotnet/api/system.invalidoperationexception) | The read service is currently not supported, especially using the `nodeIds` specified. |

## ReadNodes(IEnumerable&lt;OpcReadNode&gt;)

Reads one or more values of one or more attributes of one or more nodes using the specified `commands`.

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

```csharp
public IEnumerable<OpcValue> ReadNodes(IEnumerable<OpcReadNode> commands)
```

</div>

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

```vbnet
Public Function ReadNodes(
    commands As IEnumerable(Of OpcReadNode)) As IEnumerable(Of OpcValue)
```

</div>

**Parameters**

| Name | Type | Description |
|---|---|---|
| `commands` | [IEnumerable](https://learn.microsoft.com/dotnet/api/system.collections.generic.ienumerable-1)&lt;[OpcReadNode](https://www.traeger.de/en/docs/development/opcua/api/v2.59/opc.uafx.opcreadnode/)&gt; | A sequence of [OpcReadNode](https://www.traeger.de/en/docs/development/opcua/api/v2.59/opc.uafx.opcreadnode/) instances to process. |

**Returns**

[IEnumerable](https://learn.microsoft.com/dotnet/api/system.collections.generic.ienumerable-1)&lt;[OpcValue](https://www.traeger.de/en/docs/development/opcua/api/v2.59/opc.uafx.opcvalue/)&gt;

A sequence of [OpcValue](https://www.traeger.de/en/docs/development/opcua/api/v2.59/opc.uafx.opcvalue/) instances its number and order of items matches the number and order of items in the `commands` sequence. There is for each command one entry which stores the value requested by that command.

**Exceptions**

| Exception | Condition |
|---|---|
| [ArgumentNullException](https://learn.microsoft.com/dotnet/api/system.argumentnullexception) | The `commands` sequence or one of its items is a null reference (Nothing in Visual Basic). |
| [InvalidOperationException](https://learn.microsoft.com/dotnet/api/system.invalidoperationexception) | The read service is currently not supported, especially using the `commands` specified. |

## ReadNodes(params OpcReadNode\[\])

Reads one or more values of one or more attributes of one or more nodes using the specified `commands`.

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

```csharp
public IEnumerable<OpcValue> ReadNodes(params OpcReadNode[] commands)
```

</div>

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

```vbnet
Public Function ReadNodes(
    ParamArray commands As OpcReadNode()) As IEnumerable(Of OpcValue)
```

</div>

**Parameters**

| Name | Type | Description |
|---|---|---|
| `commands` | params [OpcReadNode](https://www.traeger.de/en/docs/development/opcua/api/v2.59/opc.uafx.opcreadnode/)[] | An array of [OpcReadNode](https://www.traeger.de/en/docs/development/opcua/api/v2.59/opc.uafx.opcreadnode/) instances to process. |

**Returns**

[IEnumerable](https://learn.microsoft.com/dotnet/api/system.collections.generic.ienumerable-1)&lt;[OpcValue](https://www.traeger.de/en/docs/development/opcua/api/v2.59/opc.uafx.opcvalue/)&gt;

A sequence of [OpcValue](https://www.traeger.de/en/docs/development/opcua/api/v2.59/opc.uafx.opcvalue/) instances its number and order of items matches the number and order of items in the `commands` sequence. There is for each command one entry which stores the value requested by that command.

**Exceptions**

| Exception | Condition |
|---|---|
| [ArgumentNullException](https://learn.microsoft.com/dotnet/api/system.argumentnullexception) | The `commands` array or one of its items is a null reference (Nothing in Visual Basic). |
| [InvalidOperationException](https://learn.microsoft.com/dotnet/api/system.invalidoperationexception) | The read service is currently not supported, especially using the `commands` specified. |