# OpcDataTypeMapper Members
> Reference: Provides an abstract implementation of the IOpcDataTypeMapper interface.
- Type
- OpcDataTypeMapper
- Namespace
- Opc.UaFx
- Assembly
- Opc.UaFx.Advanced.dll
- Package
- Opc.UaFx.Advanced v2.59.0
- Also in
- Opc.UaFx.Client
## Constructors
### OpcDataTypeMapper
protected
Initializes a new instance of the [OpcDataTypeMapper](https://www.traeger.de/en/docs/development/opcua/api/v2.59/opc.uafx.opcdatatypemapper/) class.
```csharp
protected OpcDataTypeMapper()
```
```vbnet
Protected Sub New()
```
## Properties
### SourceType
abstract
Gets the [Type](https://learn.microsoft.com/dotnet/api/system.type) from an [object](https://learn.microsoft.com/dotnet/api/system.object) can be mapped to the [TargetType](https://www.traeger.de/en/docs/development/opcua/api/v2.59/opc.uafx.opcdatatypemapper/members#targettype) using this [OpcDataTypeMapper](https://www.traeger.de/en/docs/development/opcua/api/v2.59/opc.uafx.opcdatatypemapper/).
```csharp
public abstract Type SourceType { get; }
```
```vbnet
Public MustOverride ReadOnly Property SourceType As Type
```
**Property value**
[Type](https://learn.microsoft.com/dotnet/api/system.type)
The [Type](https://learn.microsoft.com/dotnet/api/system.type) which can be mapped.
### TargetType
abstract
Gets the [Type](https://learn.microsoft.com/dotnet/api/system.type) to that an [object](https://learn.microsoft.com/dotnet/api/system.object) is mapped using this [OpcDataTypeMapper](https://www.traeger.de/en/docs/development/opcua/api/v2.59/opc.uafx.opcdatatypemapper/).
```csharp
public abstract Type TargetType { get; }
```
```vbnet
Public MustOverride ReadOnly Property TargetType As Type
```
**Property value**
[Type](https://learn.microsoft.com/dotnet/api/system.type)
The resulting [Type](https://learn.microsoft.com/dotnet/api/system.type) after mapping an [object](https://learn.microsoft.com/dotnet/api/system.object) of the [SourceType](https://www.traeger.de/en/docs/development/opcua/api/v2.59/opc.uafx.opcdatatypemapper/members#sourcetype).
## Methods
### Convert
Converts the `source`[object](https://learn.microsoft.com/dotnet/api/system.object) to a specific type.
```csharp
public object Convert(object source, IFormatProvider provider)
```
```vbnet
Public Function Convert(source As Object, provider As IFormatProvider) As Object
```
**Parameters**
| Name | Type | Description |
|---|---|---|
| `source` | [Object](https://learn.microsoft.com/dotnet/api/system.object) | The `source`[object](https://learn.microsoft.com/dotnet/api/system.object) to convert. |
| `provider` | [IFormatProvider](https://learn.microsoft.com/dotnet/api/system.iformatprovider) | The [IFormatProvider](https://learn.microsoft.com/dotnet/api/system.iformatprovider) to control any formatting which may be necessary for the convertion. |
**Returns**
[Object](https://learn.microsoft.com/dotnet/api/system.object)
The converted [object](https://learn.microsoft.com/dotnet/api/system.object) determined through the `source`[object](https://learn.microsoft.com/dotnet/api/system.object) and the `provider` specified.
**Implements**
[Convert](https://www.traeger.de/en/docs/development/opcua/api/v2.59/opc.uafx.iopcdatatypemapper/members#convert)
### ConvertBack
Converts the `target`[object](https://learn.microsoft.com/dotnet/api/system.object) to the type from which the value has been created.
```csharp
public object ConvertBack(object target, IFormatProvider provider)
```
```vbnet
Public Function ConvertBack(
target As Object,
provider As IFormatProvider) As Object
```
**Parameters**
| Name | Type | Description |
|---|---|---|
| `target` | [Object](https://learn.microsoft.com/dotnet/api/system.object) | The `target`[object](https://learn.microsoft.com/dotnet/api/system.object) to convert back. |
| `provider` | [IFormatProvider](https://learn.microsoft.com/dotnet/api/system.iformatprovider) | The [IFormatProvider](https://learn.microsoft.com/dotnet/api/system.iformatprovider) to control any formatting which may be necessary for the convertion. |
**Returns**
[Object](https://learn.microsoft.com/dotnet/api/system.object)
The source [object](https://learn.microsoft.com/dotnet/api/system.object) from which `target` has been created.
**Implements**
[ConvertBack](https://www.traeger.de/en/docs/development/opcua/api/v2.59/opc.uafx.iopcdatatypemapper/members#convertback)
### ConvertBackCore
protected · abstract
When implemented in a derived class; converts the `target`[object](https://learn.microsoft.com/dotnet/api/system.object) to the type from which the value has been created.
```csharp
protected abstract object ConvertBackCore(
object target,
IFormatProvider provider)
```
```vbnet
Protected MustOverride Function ConvertBackCore(
target As Object,
provider As IFormatProvider) As Object
```
**Parameters**
| Name | Type | Description |
|---|---|---|
| `target` | [Object](https://learn.microsoft.com/dotnet/api/system.object) | The `target`[object](https://learn.microsoft.com/dotnet/api/system.object) to convert back. |
| `provider` | [IFormatProvider](https://learn.microsoft.com/dotnet/api/system.iformatprovider) | The [IFormatProvider](https://learn.microsoft.com/dotnet/api/system.iformatprovider) to control any formatting which may be necessary for the convertion. |
**Returns**
[Object](https://learn.microsoft.com/dotnet/api/system.object)
The source [object](https://learn.microsoft.com/dotnet/api/system.object) from which `target` has been created.
**Remarks**
This method is only used in case there `target` is not a null reference (Nothing in Visual Basic).
### ConvertCore
protected · abstract
When implemented in a derived class; converts the `source`[object](https://learn.microsoft.com/dotnet/api/system.object) to a specific type.
```csharp
protected abstract object ConvertCore(object source, IFormatProvider provider)
```
```vbnet
Protected MustOverride Function ConvertCore(
source As Object,
provider As IFormatProvider) As Object
```
**Parameters**
| Name | Type | Description |
|---|---|---|
| `source` | [Object](https://learn.microsoft.com/dotnet/api/system.object) | The `source`[object](https://learn.microsoft.com/dotnet/api/system.object) to convert. |
| `provider` | [IFormatProvider](https://learn.microsoft.com/dotnet/api/system.iformatprovider) | The [IFormatProvider](https://learn.microsoft.com/dotnet/api/system.iformatprovider) to control any formatting which may be necessary for the convertion. |
**Returns**
[Object](https://learn.microsoft.com/dotnet/api/system.object)
The converted [object](https://learn.microsoft.com/dotnet/api/system.object) determined through the `source`[object](https://learn.microsoft.com/dotnet/api/system.object) and the `provider` specified.
**Remarks**
This method is only used in case there `source` is not a null reference (Nothing in Visual Basic).
### Convertible
static
Provides an [OpcDataTypeMapper](https://www.traeger.de/en/docs/development/opcua/api/v2.59/opc.uafx.opcdatatypemapper/) which utilizes the [IConvertible](https://learn.microsoft.com/dotnet/api/system.iconvertible) interface implemented by the `TSource` and `TTarget` types.
```csharp
public static OpcDataTypeMapper Convertible()
where TSource : IConvertible
where TTarget : IConvertible
```
```vbnet
Public Shared Function Convertible(Of TSource As IConvertible, TTarget As IConvertible)() As OpcDataTypeMapper
```
**Type parameters**
| Name | Description |
|---|---|
| `TSource` | The [Type](https://learn.microsoft.com/dotnet/api/system.type) implementing the [IConvertible](https://learn.microsoft.com/dotnet/api/system.iconvertible) interface and which is to be mapped to the `TTarget` type. |
| `TTarget` | The resulting [Type](https://learn.microsoft.com/dotnet/api/system.type) (implementing the [IConvertible](https://learn.microsoft.com/dotnet/api/system.iconvertible) interface) after mapping an [object](https://learn.microsoft.com/dotnet/api/system.object) of the `TSource` type. |
**Returns**
[OpcDataTypeMapper](https://www.traeger.de/en/docs/development/opcua/api/v2.59/opc.uafx.opcdatatypemapper/)
An instance of the [OpcDataTypeMapper](https://www.traeger.de/en/docs/development/opcua/api/v2.59/opc.uafx.opcdatatypemapper/) class utilizing the [IConvertible](https://learn.microsoft.com/dotnet/api/system.iconvertible) implementations of the `TSource` and `TTarget` to convert between the types.
### Delegate
static
Provides an [OpcDataTypeMapper](https://www.traeger.de/en/docs/development/opcua/api/v2.59/opc.uafx.opcdatatypemapper/) which uses the `convert` and `convertBack` delegates.
```csharp
public static OpcDataTypeMapper Delegate(
Func convert,
Func convertBack)
```
```vbnet
Public Shared Function [Delegate](Of TSource, TTarget)(
convert As Func(Of TSource, IFormatProvider, TTarget),
convertBack As Func(Of TTarget, IFormatProvider, TSource)) As OpcDataTypeMapper
```
**Type parameters**
| Name | Description |
|---|---|
| `TSource` | The [Type](https://learn.microsoft.com/dotnet/api/system.type) which is to be mapped to the `TTarget` type. |
| `TTarget` | The resulting [Type](https://learn.microsoft.com/dotnet/api/system.type) after mapping an [object](https://learn.microsoft.com/dotnet/api/system.object) of the `TSource` type. |
**Parameters**
| Name | Type | Description |
|---|---|---|
| `convert` | [Func](https://learn.microsoft.com/dotnet/api/system.func-3)<TSource, [IFormatProvider](https://learn.microsoft.com/dotnet/api/system.iformatprovider), TTarget> | The delegate to use to map the `TSource`[object](https://learn.microsoft.com/dotnet/api/system.object) to the `TTarget` type. |
| `convertBack` | [Func](https://learn.microsoft.com/dotnet/api/system.func-3)<TTarget, [IFormatProvider](https://learn.microsoft.com/dotnet/api/system.iformatprovider), TSource> | The delegate to use to map the `TTarget`[object](https://learn.microsoft.com/dotnet/api/system.object) back to the `TSource` type. |
**Returns**
[OpcDataTypeMapper](https://www.traeger.de/en/docs/development/opcua/api/v2.59/opc.uafx.opcdatatypemapper/)
**Exceptions**
| Exception | Condition |
|---|---|
| [ArgumentNullException](https://learn.microsoft.com/dotnet/api/system.argumentnullexception) | The `convert` or `convertBack` is a null reference (Nothing in Visual Basic). |