How to Use TreeView Control in Winforms C# | Fill Nodes and Select event

Find the Visual Studio project and Codes here:
https://csharp.agrimetsoft.com/exercises/TreeView_Control
How to Use #TreeView Control in #Winforms #csharp | Fill Nodes and Select event
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In this video, we’ll be looking at how to use the TreeView control in Winforms C#. We’ll be using it to fill nodes and select events.

If you’re looking to learn more about the TreeView control in Winforms C#, then this video is for you! By the end of this video, you’ll have a good understanding of how to use the TreeView control in Winforms C#, and you’ll be able to use it to fill nodes and select events!
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TreeView control is a powerful and versatile control in WinForms, which is used to display hierarchical data. It is often used to create navigation menus, file explorers, and other similar UI elements. In this tutorial, we will explore how to use the TreeView control in C# WinForms, and how to fill its nodes with data and handle the NodeSelected event.

Step 1: Add TreeView control to Form

To begin with, let’s add a TreeView control to our form. Open your WinForms project in Visual Studio and add a TreeView control to your form from the Toolbox. You can also add it programmatically.

Step 2: Add Nodes to TreeView Control

Once you have added the TreeView control to your form, the next step is to add nodes to it. A node is a hierarchical element that can contain child nodes. In other words, it is a container for other nodes.

You can add nodes to the TreeView control using the Nodes property. This property returns a collection of TreeNode objects, which you can add, remove, or modify as needed. Here is an example of adding nodes to the TreeView control:

csharp
Copy code
// Add a root node
TreeNode rootNode = new TreeNode(“Root”);
treeView1.Nodes.Add(rootNode);

// Add child nodes to the root node
rootNode.Nodes.Add(“Child 1”);
rootNode.Nodes.Add(“Child 2”);

// Add a second root node
TreeNode secondRootNode = new TreeNode(“Second Root”);
treeView1.Nodes.Add(secondRootNode);

// Add child nodes to the second root node
secondRootNode.Nodes.Add(“Child 3”);
secondRootNode.Nodes.Add(“Child 4”);
In this example, we have added two root nodes, “Root” and “Second Root”, and added child nodes to each of them.

Step 3: Fill TreeView Control with Data

In many cases, you will want to fill the TreeView control with data from an external source, such as a database or a file. To do this, you can use a recursive function that adds nodes to the TreeView control based on the data. Here is an example of how to fill the TreeView control with data:

csharp
Copy code
private void FillTreeView()
{
// Retrieve data from an external source, such as a database or a file
List<Category> categories = GetCategories();

// Create a root node for the TreeView control
TreeNode rootNode = new TreeNode(“Categories”);

// Add child nodes for each category
foreach (Category category in categories)
{
TreeNode categoryNode = new TreeNode(category.Name);
rootNode.Nodes.Add(categoryNode);

// Add child nodes for each product in the category
foreach (Product product in category.Products)
{
TreeNode productNode = new TreeNode(product.Name);
categoryNode.Nodes.Add(productNode);
}
}

// Add the root node to the TreeView control
treeView1.Nodes.Add(rootNode);
}

// Example data model classes
public class Category
{
public string Name { get; set; }
public List<Product> Products { get; set; }
}

public class Product
{
public string Name { get; set; }
public string Description { get; set; }
}
In this example, we have created a function called FillTreeView that retrieves data from an external source and adds nodes to the TreeView control based on that data. We have used two example data model classes, Category and Product, to represent the data.

Step 4: Handle NodeSelected Event

Finally, let’s see how to handle the NodeSelected event of the TreeView control. This event is raised when the user selects a node in the TreeView control.
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