# Types
### Simple Types
The[ Linx plugin](https://docs.linx.software/reference/plugins/linx) contains all Simple Types. These include:
* [Boolean](https://docs.linx.software/reference/plugins/linx/content/boolean)
* [Byte](https://docs.linx.software/reference/plugins/linx/content/byte)
* [DateTime](https://docs.linx.software/reference/plugins/linx/content/datetime)
* [Decimal](https://docs.linx.software/reference/plugins/linx/content/decimal)
* [Double](https://docs.linx.software/reference/plugins/linx/content/double)
* [Integer](https://docs.linx.software/reference/plugins/linx/content/integer)
* [String](https://docs.linx.software/reference/plugins/linx/content/string)
Use a Simple Type to create a variable in a Function by:
1. Dragging the type from the plugins panel onto the body of a Function.
2. Setting the *Value* property.
***
### Complex Types
In the Linx Designer, Complex Types are just referred to as *Types*.
A *Type* in Linx works just like a JSON object. *Types* contain collections of named properties. Each property represents a *Simple Type*, a complex *Type*, or a *List*.
**Creating a Complex Type**
1. Click the *Type* button in the toolbar to add a type to your solution.
2. Set a name for the *Type* in the Properties panel.
3. Add properties to the *Type* using the *Type Editor*:
* Add a name for each property in the *Name* column.
* Select the property type in the *Type* column dropdown.
This example shows a \*Type\* with four properties (Address is of type 'Type\_Address', Children is a List of type 'Type\_Child', DOB is of type DateTime, and Name is of type String)
Here is a JSON representation of the Type\_Person type:
{% code overflow="wrap" %}
```json
{ "Person": { "Address": { "Street": "", "City": "", "POCode": "" }, "Children": [], "DOB": "", "Name": "" } }
```
{% endcode %}
## Using a Complex Type
1. Drag the Type from the Solution Explorer onto the Function body.
2. By default, the type is instantiated as empty using squiggly brackets `{}`, but its properties are not initialized and default to null.
3. Set values for Type properties by either:
* Launching the Values Editor to add values.
```
* Using a[ SetValue](../reference/plugins/linx/content/setvalue.md) function.
```
***
### Lists
Lists can be of any simple or complex type.
#### Creating a List
1. Drag a [List](https://docs.linx.software/reference/plugins/linx/content/genericlist) from the Linx plugin onto the Function body.
2. An empty List will be initialized using square brackets `[]`.
3. Choose the List type in the property dropdown (it defaults to String).
#### Adding Items to Lists
Add items to Lists by either:
1. Launching the List editor.
1. Dragging an[ AddToList](https://docs.linx.software/reference/plugins/linx/content/addtolist) function into the Function.
2. Selecting the List and value to add in the AddToList properties.
Other functions to manipulate the list are available in the Linx plugin.
***
### Assignment Errors
A common problem is caused by the attempt to assign values to NULL elements.
1. To set a value for a property of a complex type, the type cannot be null.
2. Instantiate a Complex type inside another one with `{"PropertyName":{}}`.
3. Lists must be instantiated before they can be added to.
4. Instantiate Lists that are properties of complex types with `{"PropertyName":[]}`.
***
### Tutorial Video
{% embed url="" %}
