> For the complete documentation index, see [llms.txt](https://docs.wisej.com/api/llms.txt). Markdown versions of documentation pages are available by appending `.md` to page URLs; this page is available as [Markdown](https://docs.wisej.com/api/wisej.web/lists-and-grids/treeview/wisej.web.treenodecollection.md).

# TreeNodeCollection

Namespace: **Wisej.Web**

Assembly: **Wisej.Framework** (4.0.0.0)

Represents a collection of [TreeNode](/api/wisej.web/lists-and-grids/treeview/wisej.web.treenode.md) objects.

{% tabs %}
{% tab title="C#" %}

```csharp
public class TreeNodeCollection : IList, ICollection, IEnumerable, IList<TreeNode>, ICollection<TreeNode>, IEnumerable<TreeNode>
```

{% endtab %}

{% tab title="VB.NET" %}

```visual-basic
Public Class TreeNodeCollection
    Inherits IList
    Implements ICollection, IEnumerable, IList(Of TreeNode), ICollection(Of TreeNode), IEnumerable(Of TreeNode)
```

{% endtab %}
{% endtabs %}

## Properties

### ![](/files/hsR4ok3152WyAf8J2C1u) Count

[Int32](https://docs.microsoft.com/dotnet/api/system.int32): Returns the total number of [TreeNode](/api/wisej.web/lists-and-grids/treeview/wisej.web.treenode.md) objects in the collection.

### ![](/files/hsR4ok3152WyAf8J2C1u) IsReadOnly

[Boolean](https://docs.microsoft.com/dotnet/api/system.boolean): Returns a value indicating whether the collection is read-only.

### ![](/files/hsR4ok3152WyAf8J2C1u) Item(index)

[TreeNode](/api/wisej.web/lists-and-grids/treeview/wisej.web.treenode.md): Returns or sets the [TreeNode](/api/wisej.web/lists-and-grids/treeview/wisej.web.treenode.md) at the specified index in the collection.

**Throws:**

* [ArgumentException](https://docs.microsoft.com/dotnet/api/system.argumentexception)\
  The [TreeNode](/api/wisej.web/lists-and-grids/treeview/wisej.web.treenode.md) being assigned is also a parent causing a circular reference.
* [ArgumentNullException](https://docs.microsoft.com/dotnet/api/system.argumentnullexception)\
  The value is null.
* [ArgumentOutOfRangeException](https://docs.microsoft.com/dotnet/api/system.argumentoutofrangeexception)\
  The *index* value is less than 0 or is greater than the number of tree nodes in the collection.

### ![](/files/hsR4ok3152WyAf8J2C1u) Item(key)

[TreeNode](/api/wisej.web/lists-and-grids/treeview/wisej.web.treenode.md): Returns the [TreeNode](/api/wisej.web/lists-and-grids/treeview/wisej.web.treenode.md) with the specified key from the collection.

## Methods

### ![](/files/hsR4ok3152WyAf8J2C1u) Add(text)

Adds a new tree node with the specified label text to the end of the current [TreeNodeCollection](/api/wisej.web/lists-and-grids/treeview/wisej.web.treenodecollection.md).

| Parameter | Type                                                          | Description                                                                                                |
| --------- | ------------------------------------------------------------- | ---------------------------------------------------------------------------------------------------------- |
| **text**  | [String](https://docs.microsoft.com/dotnet/api/system.string) | The label text displayed by the [TreeNode](/api/wisej.web/lists-and-grids/treeview/wisej.web.treenode.md). |

**Returns:** [TreeNode](/api/wisej.web/lists-and-grids/treeview/wisej.web.treenode.md). A [TreeNode](/api/wisej.web/lists-and-grids/treeview/wisej.web.treenode.md) that represents the tree node being added to the collection.

### ![](/files/hsR4ok3152WyAf8J2C1u) Add(key, text)

Creates a new [TreeNode](/api/wisej.web/lists-and-grids/treeview/wisej.web.treenode.md) with the specified key and text, and adds it to the collection.

| Parameter | Type                                                          | Description                                                                                           |
| --------- | ------------------------------------------------------------- | ----------------------------------------------------------------------------------------------------- |
| **key**   | [String](https://docs.microsoft.com/dotnet/api/system.string) | The name of the [TreeNode](/api/wisej.web/lists-and-grids/treeview/wisej.web.treenode.md).            |
| **text**  | [String](https://docs.microsoft.com/dotnet/api/system.string) | The text to display in the [TreeNode](/api/wisej.web/lists-and-grids/treeview/wisej.web.treenode.md). |

**Returns:** [TreeNode](/api/wisej.web/lists-and-grids/treeview/wisej.web.treenode.md). The [TreeNode](/api/wisej.web/lists-and-grids/treeview/wisej.web.treenode.md) that was added to the collection.

### ![](/files/hsR4ok3152WyAf8J2C1u) Add(key, text, imageIndex)

Creates a [TreeNode](/api/wisej.web/lists-and-grids/treeview/wisej.web.treenode.md) with the specified key, text, and image, and adds it to the collection.

| Parameter      | Type                                                          | Description                                                                                                         |
| -------------- | ------------------------------------------------------------- | ------------------------------------------------------------------------------------------------------------------- |
| **key**        | [String](https://docs.microsoft.com/dotnet/api/system.string) | The name of the [TreeNode](/api/wisej.web/lists-and-grids/treeview/wisej.web.treenode.md).                          |
| **text**       | [String](https://docs.microsoft.com/dotnet/api/system.string) | The text to display in the [TreeNode](/api/wisej.web/lists-and-grids/treeview/wisej.web.treenode.md).               |
| **imageIndex** | [Int32](https://docs.microsoft.com/dotnet/api/system.int32)   | The index of the image to display in the [TreeNode](/api/wisej.web/lists-and-grids/treeview/wisej.web.treenode.md). |

**Returns:** [TreeNode](/api/wisej.web/lists-and-grids/treeview/wisej.web.treenode.md). The [TreeNode](/api/wisej.web/lists-and-grids/treeview/wisej.web.treenode.md) that was added to the collection.

### ![](/files/hsR4ok3152WyAf8J2C1u) Add(key, text, imageKey)

Creates a [TreeNode](/api/wisej.web/lists-and-grids/treeview/wisej.web.treenode.md) with the specified key, text, and image, and adds it to the collection.

| Parameter    | Type                                                          | Description                                                                                            |
| ------------ | ------------------------------------------------------------- | ------------------------------------------------------------------------------------------------------ |
| **key**      | [String](https://docs.microsoft.com/dotnet/api/system.string) | The name of the [TreeNode](/api/wisej.web/lists-and-grids/treeview/wisej.web.treenode.md).             |
| **text**     | [String](https://docs.microsoft.com/dotnet/api/system.string) | The text to display in the [TreeNode](/api/wisej.web/lists-and-grids/treeview/wisej.web.treenode.md).  |
| **imageKey** | [String](https://docs.microsoft.com/dotnet/api/system.string) | The image to display in the [TreeNode](/api/wisej.web/lists-and-grids/treeview/wisej.web.treenode.md). |

**Returns:** [TreeNode](/api/wisej.web/lists-and-grids/treeview/wisej.web.treenode.md). The [TreeNode](/api/wisej.web/lists-and-grids/treeview/wisej.web.treenode.md) that was added to the collection.

### ![](/files/hsR4ok3152WyAf8J2C1u) Add(key, text, imageIndex, selectedImageIndex)

Creates a [TreeNode](/api/wisej.web/lists-and-grids/treeview/wisej.web.treenode.md) with the specified key, text, and images, and adds it to the collection.

| Parameter              | Type                                                          | Description                                                                                                         |
| ---------------------- | ------------------------------------------------------------- | ------------------------------------------------------------------------------------------------------------------- |
| **key**                | [String](https://docs.microsoft.com/dotnet/api/system.string) | The name of the [TreeNode](/api/wisej.web/lists-and-grids/treeview/wisej.web.treenode.md).                          |
| **text**               | [String](https://docs.microsoft.com/dotnet/api/system.string) | The text to display in the [TreeNode](/api/wisej.web/lists-and-grids/treeview/wisej.web.treenode.md).               |
| **imageIndex**         | [Int32](https://docs.microsoft.com/dotnet/api/system.int32)   | The index of the image to display in the [TreeNode](/api/wisej.web/lists-and-grids/treeview/wisej.web.treenode.md). |
| **selectedImageIndex** | [Int32](https://docs.microsoft.com/dotnet/api/system.int32)   | The index of the image to be displayed in the tree node when it is in a selected state.                             |

**Returns:** [TreeNode](/api/wisej.web/lists-and-grids/treeview/wisej.web.treenode.md). The tree node that was added to the collection.

### ![](/files/hsR4ok3152WyAf8J2C1u) Add(key, text, imageKey, selectedImageKey)

Creates a [TreeNode](/api/wisej.web/lists-and-grids/treeview/wisej.web.treenode.md) with the specified key, text, and images, and adds it to the collection.

| Parameter            | Type                                                          | Description                                                                                                       |
| -------------------- | ------------------------------------------------------------- | ----------------------------------------------------------------------------------------------------------------- |
| **key**              | [String](https://docs.microsoft.com/dotnet/api/system.string) | The name of the [TreeNode](/api/wisej.web/lists-and-grids/treeview/wisej.web.treenode.md).                        |
| **text**             | [String](https://docs.microsoft.com/dotnet/api/system.string) | The text to display in the [TreeNode](/api/wisej.web/lists-and-grids/treeview/wisej.web.treenode.md).             |
| **imageKey**         | [String](https://docs.microsoft.com/dotnet/api/system.string) | The key of the image to display in the [TreeNode](/api/wisej.web/lists-and-grids/treeview/wisej.web.treenode.md). |
| **selectedImageKey** | [String](https://docs.microsoft.com/dotnet/api/system.string) | The key of the image to display when the node is in a selected state.                                             |

**Returns:** [TreeNode](/api/wisej.web/lists-and-grids/treeview/wisej.web.treenode.md). The [TreeNode](/api/wisej.web/lists-and-grids/treeview/wisej.web.treenode.md) that was added to the collection.

### ![](/files/hsR4ok3152WyAf8J2C1u) Add(node)

Adds a previously created [TreeNode](/api/wisej.web/lists-and-grids/treeview/wisej.web.treenode.md) to the end of the [TreeNodeCollection](/api/wisej.web/lists-and-grids/treeview/wisej.web.treenodecollection.md).

| Parameter | Type                                                                      | Description                                                                                             |
| --------- | ------------------------------------------------------------------------- | ------------------------------------------------------------------------------------------------------- |
| **node**  | [TreeNode](/api/wisej.web/lists-and-grids/treeview/wisej.web.treenode.md) | The [TreeNode](/api/wisej.web/lists-and-grids/treeview/wisej.web.treenode.md) to add to the collection. |

**Returns:** [Int32](https://docs.microsoft.com/dotnet/api/system.int32). The zero-based index value of the [TreeNode](/api/wisej.web/lists-and-grids/treeview/wisej.web.treenode.md) added to the [TreeNodeCollection](/api/wisej.web/lists-and-grids/treeview/wisej.web.treenodecollection.md).

**Throws:**

* [ArgumentNullException](https://docs.microsoft.com/dotnet/api/system.argumentnullexception)*node* is null.
* [ArgumentException](https://docs.microsoft.com/dotnet/api/system.argumentexception)\
  The *node* is currently assigned to another [TreeView](/api/wisej.web/lists-and-grids/treeview.md) or it is a parent node causing a circular reference.

### ![](/files/hsR4ok3152WyAf8J2C1u) AddRange(nodes)

Adds an array of previously created [TreeNode](/api/wisej.web/lists-and-grids/treeview/wisej.web.treenode.md) objects to the collection.

| Parameter | Type                                                                          | Description                                                                                                                                         |
| --------- | ----------------------------------------------------------------------------- | --------------------------------------------------------------------------------------------------------------------------------------------------- |
| **nodes** | [TreeNode\[\]](/api/wisej.web/lists-and-grids/treeview/wisej.web.treenode.md) | An array of [TreeNode](/api/wisej.web/lists-and-grids/treeview/wisej.web.treenode.md) objects representing the tree nodes to add to the collection. |

**Throws:**

* [ArgumentNullException](https://docs.microsoft.com/dotnet/api/system.argumentnullexception)*nodes* is null or one of the items in the collection is null.
* [ArgumentException](https://docs.microsoft.com/dotnet/api/system.argumentexception)*nodes* is the child of another [TreeView](/api/wisej.web/lists-and-grids/treeview.md).

### ![](/files/hsR4ok3152WyAf8J2C1u) Clear()

Removes all tree nodes from the collection.

### ![](/files/hsR4ok3152WyAf8J2C1u) Clear(dispose)

Removes and disposes all tree nodes from the collection.

| Parameter   | Type                                                            | Description                                                              |
| ----------- | --------------------------------------------------------------- | ------------------------------------------------------------------------ |
| **dispose** | [Boolean](https://docs.microsoft.com/dotnet/api/system.boolean) | Indicates whether to dispose the tree nodes removed from the collection. |

### ![](/files/hsR4ok3152WyAf8J2C1u) Contains(node)

Determines whether the specified [TreeNode](/api/wisej.web/lists-and-grids/treeview/wisej.web.treenode.md) is a member of the collection.

| Parameter | Type                                                                      | Description                                                                                                |
| --------- | ------------------------------------------------------------------------- | ---------------------------------------------------------------------------------------------------------- |
| **node**  | [TreeNode](/api/wisej.web/lists-and-grids/treeview/wisej.web.treenode.md) | The [TreeNode](/api/wisej.web/lists-and-grids/treeview/wisej.web.treenode.md) to locate in the collection. |

**Returns:** [Boolean](https://docs.microsoft.com/dotnet/api/system.boolean). true if the [TreeNode](/api/wisej.web/lists-and-grids/treeview/wisej.web.treenode.md) is a member of the collection; otherwise, false.

### ![](/files/hsR4ok3152WyAf8J2C1u) ContainsKey(key)

Determines whether the collection contains a [TreeNode](/api/wisej.web/lists-and-grids/treeview/wisej.web.treenode.md) with the specified key.

| Parameter | Type                                                          | Description                                                                                              |
| --------- | ------------------------------------------------------------- | -------------------------------------------------------------------------------------------------------- |
| **key**   | [String](https://docs.microsoft.com/dotnet/api/system.string) | The name of the [TreeNode](/api/wisej.web/lists-and-grids/treeview/wisej.web.treenode.md) to search for. |

**Returns:** [Boolean](https://docs.microsoft.com/dotnet/api/system.boolean). true to indicate the collection contains a [TreeNode](/api/wisej.web/lists-and-grids/treeview/wisej.web.treenode.md) with the specified key; otherwise, false.

### ![](/files/hsR4ok3152WyAf8J2C1u) CopyTo(dest, index)

Copies the entire collection into an existing array at a specified location within the array.

| Parameter | Type                                                        | Description                                                 |
| --------- | ----------------------------------------------------------- | ----------------------------------------------------------- |
| **dest**  | [Array](https://docs.microsoft.com/dotnet/api/system.array) | The destination array.                                      |
| **index** | [Int32](https://docs.microsoft.com/dotnet/api/system.int32) | The index in the destination array at which storing begins. |

### ![](/files/hsR4ok3152WyAf8J2C1u) Find(key, searchAllChildren)

Finds the [TreeNode](/api/wisej.web/lists-and-grids/treeview/wisej.web.treenode.md) objects with specified key, optionally searching sub nodes.

| Parameter             | Type                                                            | Description                                                 |
| --------------------- | --------------------------------------------------------------- | ----------------------------------------------------------- |
| **key**               | [String](https://docs.microsoft.com/dotnet/api/system.string)   | The name of the tree node to search for.                    |
| **searchAllChildren** | [Boolean](https://docs.microsoft.com/dotnet/api/system.boolean) | true to search child nodes of tree nodes; otherwise, false. |

**Returns:** [TreeNode\[\]](/api/wisej.web/lists-and-grids/treeview/wisej.web.treenode.md). An array of [TreeNode](/api/wisej.web/lists-and-grids/treeview/wisej.web.treenode.md) objects whose [Name](/api/wisej.web/lists-and-grids/treeview/wisej.web.treenode.md#name) property matches the specified key.

### ![](/files/hsR4ok3152WyAf8J2C1u) GetEnumerator()

Returns an enumerator that can be used to iterate through the [TreeNodeCollection](/api/wisej.web/lists-and-grids/treeview/wisej.web.treenodecollection.md).

**Returns:** [IEnumerator\<TreeNode>](https://docs.microsoft.com/dotnet/api/system.collections.generic.ienumerator-1). An [IEnumerator](https://docs.microsoft.com/dotnet/api/system.collections.ienumerator) that represents the [TreeNodeCollection](/api/wisej.web/lists-and-grids/treeview/wisej.web.treenodecollection.md).

### ![](/files/hsR4ok3152WyAf8J2C1u) IndexOf(node)

Returns the index of the specified [TreeNode](/api/wisej.web/lists-and-grids/treeview/wisej.web.treenode.md) in the collection.

| Parameter | Type                                                                      | Description                                                                                                |
| --------- | ------------------------------------------------------------------------- | ---------------------------------------------------------------------------------------------------------- |
| **node**  | [TreeNode](/api/wisej.web/lists-and-grids/treeview/wisej.web.treenode.md) | The [TreeNode](/api/wisej.web/lists-and-grids/treeview/wisej.web.treenode.md) to locate in the collection. |

**Returns:** [Int32](https://docs.microsoft.com/dotnet/api/system.int32). The zero-based index of the item found in the tree node collection; otherwise, -1.

### ![](/files/hsR4ok3152WyAf8J2C1u) IndexOfKey(key)

Returns the index of the first occurrence of a [TreeNode](/api/wisej.web/lists-and-grids/treeview/wisej.web.treenode.md) with the specified key.

| Parameter | Type                                                          | Description                              |
| --------- | ------------------------------------------------------------- | ---------------------------------------- |
| **key**   | [String](https://docs.microsoft.com/dotnet/api/system.string) | The name of the tree node to search for. |

**Returns:** [Int32](https://docs.microsoft.com/dotnet/api/system.int32). The zero-based index of the first occurrence of a tree node with the specified key, if found; otherwise, -1.

### ![](/files/hsR4ok3152WyAf8J2C1u) Insert(index, node)

Inserts an existing tree node into the tree node collection at the specified location.

| Parameter | Type                                                                      | Description                                                                                                                         |
| --------- | ------------------------------------------------------------------------- | ----------------------------------------------------------------------------------------------------------------------------------- |
| **index** | [Int32](https://docs.microsoft.com/dotnet/api/system.int32)               | The indexed location within the collection to insert the [TreeNode](/api/wisej.web/lists-and-grids/treeview/wisej.web.treenode.md). |
| **node**  | [TreeNode](/api/wisej.web/lists-and-grids/treeview/wisej.web.treenode.md) | The [TreeNode](/api/wisej.web/lists-and-grids/treeview/wisej.web.treenode.md) to insert into the collection.                        |

**Throws:**

* [ArgumentNullException](https://docs.microsoft.com/dotnet/api/system.argumentnullexception)*node* is null.
* [ArgumentException](https://docs.microsoft.com/dotnet/api/system.argumentexception)\
  The *node* is currently assigned to another [TreeView](/api/wisej.web/lists-and-grids/treeview.md) or it is a parent node causing a circular reference.

### ![](/files/hsR4ok3152WyAf8J2C1u) Insert(index, text)

Creates a [TreeNode](/api/wisej.web/lists-and-grids/treeview/wisej.web.treenode.md) with the specified text and inserts it at the specified index.

| Parameter | Type                                                          | Description                                                                                                                 |
| --------- | ------------------------------------------------------------- | --------------------------------------------------------------------------------------------------------------------------- |
| **index** | [Int32](https://docs.microsoft.com/dotnet/api/system.int32)   | The location within the collection to insert the [TreeNode](/api/wisej.web/lists-and-grids/treeview/wisej.web.treenode.md). |
| **text**  | [String](https://docs.microsoft.com/dotnet/api/system.string) | The text to display in the [TreeNode](/api/wisej.web/lists-and-grids/treeview/wisej.web.treenode.md).                       |

**Returns:** [TreeNode](/api/wisej.web/lists-and-grids/treeview/wisej.web.treenode.md). The [TreeNode](/api/wisej.web/lists-and-grids/treeview/wisej.web.treenode.md) that was inserted in the collection.

### ![](/files/hsR4ok3152WyAf8J2C1u) Insert(index, key, text)

Creates a tree node with the specified text and key, and inserts it into the collection.

| Parameter | Type                                                          | Description                                                                                                                 |
| --------- | ------------------------------------------------------------- | --------------------------------------------------------------------------------------------------------------------------- |
| **index** | [Int32](https://docs.microsoft.com/dotnet/api/system.int32)   | The location within the collection to insert the [TreeNode](/api/wisej.web/lists-and-grids/treeview/wisej.web.treenode.md). |
| **key**   | [String](https://docs.microsoft.com/dotnet/api/system.string) | The name of the [TreeNode](/api/wisej.web/lists-and-grids/treeview/wisej.web.treenode.md).                                  |
| **text**  | [String](https://docs.microsoft.com/dotnet/api/system.string) | The text to display in the [TreeNode](/api/wisej.web/lists-and-grids/treeview/wisej.web.treenode.md).                       |

**Returns:** [TreeNode](/api/wisej.web/lists-and-grids/treeview/wisej.web.treenode.md). The [TreeNode](/api/wisej.web/lists-and-grids/treeview/wisej.web.treenode.md) that was inserted in the collection.

### ![](/files/hsR4ok3152WyAf8J2C1u) Insert(index, key, text, imageIndex)

Creates a [TreeNode](/api/wisej.web/lists-and-grids/treeview/wisej.web.treenode.md) with the specified key, text, and image, and inserts it into the collection at the specified index.

| Parameter      | Type                                                          | Description                                                                                                                 |
| -------------- | ------------------------------------------------------------- | --------------------------------------------------------------------------------------------------------------------------- |
| **index**      | [Int32](https://docs.microsoft.com/dotnet/api/system.int32)   | The location within the collection to insert the [TreeNode](/api/wisej.web/lists-and-grids/treeview/wisej.web.treenode.md). |
| **key**        | [String](https://docs.microsoft.com/dotnet/api/system.string) | The name of the [TreeNode](/api/wisej.web/lists-and-grids/treeview/wisej.web.treenode.md).                                  |
| **text**       | [String](https://docs.microsoft.com/dotnet/api/system.string) | The text to display in the [TreeNode](/api/wisej.web/lists-and-grids/treeview/wisej.web.treenode.md).                       |
| **imageIndex** | [Int32](https://docs.microsoft.com/dotnet/api/system.int32)   | The index of the image to display in the [TreeNode](/api/wisej.web/lists-and-grids/treeview/wisej.web.treenode.md).         |

**Returns:** [TreeNode](/api/wisej.web/lists-and-grids/treeview/wisej.web.treenode.md). The [TreeNode](/api/wisej.web/lists-and-grids/treeview/wisej.web.treenode.md) that was inserted in the collection.

### ![](/files/hsR4ok3152WyAf8J2C1u) Insert(index, key, text, imageKey)

Creates a [TreeNode](/api/wisej.web/lists-and-grids/treeview/wisej.web.treenode.md) with the specified key, text, and image, and inserts it into the collection at the specified index.

| Parameter    | Type                                                          | Description                                                                                                                 |
| ------------ | ------------------------------------------------------------- | --------------------------------------------------------------------------------------------------------------------------- |
| **index**    | [Int32](https://docs.microsoft.com/dotnet/api/system.int32)   | The location within the collection to insert the [TreeNode](/api/wisej.web/lists-and-grids/treeview/wisej.web.treenode.md). |
| **key**      | [String](https://docs.microsoft.com/dotnet/api/system.string) | The name of the [TreeNode](/api/wisej.web/lists-and-grids/treeview/wisej.web.treenode.md).                                  |
| **text**     | [String](https://docs.microsoft.com/dotnet/api/system.string) | The text to display in the [TreeNode](/api/wisej.web/lists-and-grids/treeview/wisej.web.treenode.md).                       |
| **imageKey** | [String](https://docs.microsoft.com/dotnet/api/system.string) | The key of the image to display in the [TreeNode](/api/wisej.web/lists-and-grids/treeview/wisej.web.treenode.md).           |

**Returns:** [TreeNode](/api/wisej.web/lists-and-grids/treeview/wisej.web.treenode.md). The [TreeNode](/api/wisej.web/lists-and-grids/treeview/wisej.web.treenode.md) that was inserted in the collection.

### ![](/files/hsR4ok3152WyAf8J2C1u) Insert(index, key, text, imageIndex, selectedImageIndex)

Creates a [TreeNode](/api/wisej.web/lists-and-grids/treeview/wisej.web.treenode.md) with the specified key, text, and images, and inserts it into the collection at the specified index.

| Parameter              | Type                                                          | Description                                                                                                                                        |
| ---------------------- | ------------------------------------------------------------- | -------------------------------------------------------------------------------------------------------------------------------------------------- |
| **index**              | [Int32](https://docs.microsoft.com/dotnet/api/system.int32)   | The location within the collection to insert the [TreeNode](/api/wisej.web/lists-and-grids/treeview/wisej.web.treenode.md).                        |
| **key**                | [String](https://docs.microsoft.com/dotnet/api/system.string) | The name of the [TreeNode](/api/wisej.web/lists-and-grids/treeview/wisej.web.treenode.md).                                                         |
| **text**               | [String](https://docs.microsoft.com/dotnet/api/system.string) | The text to display in the [TreeNode](/api/wisej.web/lists-and-grids/treeview/wisej.web.treenode.md).                                              |
| **imageIndex**         | [Int32](https://docs.microsoft.com/dotnet/api/system.int32)   | The index of the image to display in the [TreeNode](/api/wisej.web/lists-and-grids/treeview/wisej.web.treenode.md).                                |
| **selectedImageIndex** | [Int32](https://docs.microsoft.com/dotnet/api/system.int32)   | The index of the image to display in the [TreeNode](/api/wisej.web/lists-and-grids/treeview/wisej.web.treenode.md) when it is in a selected state. |

**Returns:** [TreeNode](/api/wisej.web/lists-and-grids/treeview/wisej.web.treenode.md). The [TreeNode](/api/wisej.web/lists-and-grids/treeview/wisej.web.treenode.md) that was inserted in the collection.

### ![](/files/hsR4ok3152WyAf8J2C1u) Insert(index, key, text, imageKey, selectedImageKey)

Creates a [TreeNode](/api/wisej.web/lists-and-grids/treeview/wisej.web.treenode.md) with the specified key, text, and images, and inserts it into the collection at the specified index.

| Parameter            | Type                                                          | Description                                                                                                                                      |
| -------------------- | ------------------------------------------------------------- | ------------------------------------------------------------------------------------------------------------------------------------------------ |
| **index**            | [Int32](https://docs.microsoft.com/dotnet/api/system.int32)   | The location within the collection to insert the [TreeNode](/api/wisej.web/lists-and-grids/treeview/wisej.web.treenode.md).                      |
| **key**              | [String](https://docs.microsoft.com/dotnet/api/system.string) | The name of the [TreeNode](/api/wisej.web/lists-and-grids/treeview/wisej.web.treenode.md).                                                       |
| **text**             | [String](https://docs.microsoft.com/dotnet/api/system.string) | The text to display in the [TreeNode](/api/wisej.web/lists-and-grids/treeview/wisej.web.treenode.md).                                            |
| **imageKey**         | [String](https://docs.microsoft.com/dotnet/api/system.string) | The key of the image to display in the [TreeNode](/api/wisej.web/lists-and-grids/treeview/wisej.web.treenode.md).                                |
| **selectedImageKey** | [String](https://docs.microsoft.com/dotnet/api/system.string) | The key of the image to display in the [TreeNode](/api/wisej.web/lists-and-grids/treeview/wisej.web.treenode.md) when it is in a selected state. |

**Returns:** [TreeNode](/api/wisej.web/lists-and-grids/treeview/wisej.web.treenode.md). The [TreeNode](/api/wisej.web/lists-and-grids/treeview/wisej.web.treenode.md) that was inserted in the collection.

### ![](/files/lzopMboA31bVq8UIcbT3) OnCollectionChanged(action, element)

Fires the [CollectionChanged](#collectionchanged) event.

| Parameter   | Type                                                                                                         | Description                                                                                                                                                           |
| ----------- | ------------------------------------------------------------------------------------------------------------ | --------------------------------------------------------------------------------------------------------------------------------------------------------------------- |
| **action**  | [CollectionChangeAction](https://docs.microsoft.com/dotnet/api/system.componentmodel.collectionchangeaction) | One of [CollectionChangeAction](https://docs.microsoft.com/dotnet/api/system.componentmodel.collectionchangeaction) indicating the reason the collection has changed. |
| **element** | [Object](https://docs.microsoft.com/dotnet/api/system.object)                                                | The element that was added or removed from the collection, or null.                                                                                                   |

### ![](/files/hsR4ok3152WyAf8J2C1u) Remove(node)

Removes the specified [TreeNode](/api/wisej.web/lists-and-grids/treeview/wisej.web.treenode.md) from the [TreeNodeCollection](/api/wisej.web/lists-and-grids/treeview/wisej.web.treenodecollection.md).

| Parameter | Type                                                                      | Description                                                                              |
| --------- | ------------------------------------------------------------------------- | ---------------------------------------------------------------------------------------- |
| **node**  | [TreeNode](/api/wisej.web/lists-and-grids/treeview/wisej.web.treenode.md) | The [TreeNode](/api/wisej.web/lists-and-grids/treeview/wisej.web.treenode.md) to remove. |

**Throws:**

* [ArgumentNullException](https://docs.microsoft.com/dotnet/api/system.argumentnullexception)*node* is null.

### ![](/files/hsR4ok3152WyAf8J2C1u) RemoveAt(index)

Removes a tree node from the tree node collection at a specified index.

| Parameter | Type                                                        | Description                                                                                           |
| --------- | ----------------------------------------------------------- | ----------------------------------------------------------------------------------------------------- |
| **index** | [Int32](https://docs.microsoft.com/dotnet/api/system.int32) | The index of the [TreeNode](/api/wisej.web/lists-and-grids/treeview/wisej.web.treenode.md) to remove. |

### ![](/files/hsR4ok3152WyAf8J2C1u) RemoveByKey(key)

Removes the [TreeNode](/api/wisej.web/lists-and-grids/treeview/wisej.web.treenode.md) with the specified key from the collection.

| Parameter | Type                                                          | Description                                              |
| --------- | ------------------------------------------------------------- | -------------------------------------------------------- |
| **key**   | [String](https://docs.microsoft.com/dotnet/api/system.string) | The name of the tree node to remove from the collection. |

## Events

### ![](/files/hsR4ok3152WyAf8J2C1u) CollectionChanged

[CollectionChangeEventHandler](https://docs.microsoft.com/dotnet/api/system.componentmodel.collectionchangeeventhandler) Fired when the collection changes.


---

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