To-Do List Application in C#

June 10, 2024

To-Do List Application in C# - Base Level

Building a Simple To-Do List Application in C#

Creating a simple to-do list application is a great way to get started with C# and understand the basics of Windows Forms, a GUI toolkit included in the .NET framework. This guide will walk you through the process of building a basic to-do list application using C#.

Prerequisites

Visual Studio: Install the latest version of Visual Studio with the .NET desktop development workload.
Basic Knowledge of C#: Familiarity with C# programming is recommended.

Step 1: Create a New Windows Forms Project

Open Visual Studio: Start Visual Studio and select "Create a new project."
Select Project Template: Choose "Windows Forms App (.NET Framework)" and click "Next."
Configure Project: Enter a project name (e.g., "ToDoListApp"), choose a location, and click "Create."

Step 2: Design the User Interface

Form Layout: Open Form1.cs in the designer view.
Add Controls:
- TextBox: For entering new to-do items.
- Button: For adding items to the list.
- ListBox: For displaying the list of to-do items.
- Button: For removing selected items from the list.
Arrange Controls: Arrange the controls on the form to your liking.

Example Layout:

TextBox: Place at the top for new item entry.
Add Button: Next to the TextBox to add the item.
ListBox: Below the TextBox and Add Button to display the items.
Remove Button: Below the ListBox to remove selected items.

Step 3: Write the Code

Initialize the Form: Open Form1.cs in the code view.
Add Event Handlers: Double-click the Add and Remove buttons in the designer to generate click event handlers.

Implement Add Button Logic:

csharp

private void addButton_Click(object sender, EventArgs e)
{
    string newItem = newItemTextBox.Text;
    if (!string.IsNullOrWhiteSpace(newItem))
    {
        todoListBox.Items.Add(newItem);
        newItemTextBox.Clear();
    }
    else
    {
        MessageBox.Show("Please enter a valid to-do item.", "Invalid Input", MessageBoxButtons.OK, MessageBoxIcon.Warning);
    }
}

Implement Remove Button Logic:

csharp

private void removeButton_Click(object sender, EventArgs e)
{
    if (todoListBox.SelectedItem != null)
    {
        todoListBox.Items.Remove(todoListBox.SelectedItem);
    }
    else
    {
        MessageBox.Show("Please select an item to remove.", "No Selection", MessageBoxButtons.OK, MessageBoxIcon.Warning);
    }
}

Form Load Event (Optional): You can initialize the form with some sample data or other settings.

csharp

private void Form1_Load(object sender, EventArgs e)
{
    // Sample data (optional)
    todoListBox.Items.Add("Sample Task 1");
    todoListBox.Items.Add("Sample Task 2");
}

Step 4: Run the Application

Build and Run: Press F5 to build and run the application. Ensure there are no errors.
Test Functionality: Add, view, and remove to-do items to test the application.

Complete Code Example

Form1.Designer.cs:

csharp

partial class Form1
{
    private System.ComponentModel.IContainer components = null;
    private System.Windows.Forms.TextBox newItemTextBox;
    private System.Windows.Forms.Button addButton;
    private System.Windows.Forms.ListBox todoListBox;
    private System.Windows.Forms.Button removeButton;

    private void InitializeComponent()
    {
        this.newItemTextBox = new System.Windows.Forms.TextBox();
        this.addButton = new System.Windows.Forms.Button();
        this.todoListBox = new System.Windows.Forms.ListBox();
        this.removeButton = new System.Windows.Forms.Button();
        this.SuspendLayout();
        
        // 
        // newItemTextBox
        // 
        this.newItemTextBox.Location = new System.Drawing.Point(12, 12);
        this.newItemTextBox.Name = "newItemTextBox";
        this.newItemTextBox.Size = new System.Drawing.Size(260, 20);
        this.newItemTextBox.TabIndex = 0;
        
        // 
        // addButton
        // 
        this.addButton.Location = new System.Drawing.Point(278, 10);
        this.addButton.Name = "addButton";
        this.addButton.Size = new System.Drawing.Size(75, 23);
        this.addButton.TabIndex = 1;
        this.addButton.Text = "Add";
        this.addButton.UseVisualStyleBackColor = true;
        this.addButton.Click += new System.EventHandler(this.addButton_Click);
        
        // 
        // todoListBox
        // 
        this.todoListBox.FormattingEnabled = true;
        this.todoListBox.Location = new System.Drawing.Point(12, 38);
        this.todoListBox.Name = "todoListBox";
        this.todoListBox.Size = new System.Drawing.Size(341, 199);
        this.todoListBox.TabIndex = 2;
        
        // 
        // removeButton
        // 
        this.removeButton.Location = new System.Drawing.Point(12, 243);
        this.removeButton.Name = "removeButton";
        this.removeButton.Size = new System.Drawing.Size(341, 23);
        this.removeButton.TabIndex = 3;
        this.removeButton.Text = "Remove";
        this.removeButton.UseVisualStyleBackColor = true;
        this.removeButton.Click += new System.EventHandler(this.removeButton_Click);
        
        // 
        // Form1
        // 
        this.AutoScaleDimensions = new System.Drawing.SizeF(6F, 13F);
        this.AutoScaleMode = System.Windows.Forms.AutoScaleMode.Font;
        this.ClientSize = new System.Drawing.Size(365, 278);
        this.Controls.Add(this.removeButton);
        this.Controls.Add(this.todoListBox);
        this.Controls.Add(this.addButton);
        this.Controls.Add(this.newItemTextBox);
        this.Name = "Form1";
        this.Text = "To-Do List";
        this.Load += new System.EventHandler(this.Form1_Load);
        this.ResumeLayout(false);
        this.PerformLayout();
    }
}

Form1.cs:

csharp

public partial class Form1 : Form
{
    public Form1()
    {
        InitializeComponent();
    }

    private void addButton_Click(object sender, EventArgs e)
    {
        string newItem = newItemTextBox.Text;
        if (!string.IsNullOrWhiteSpace(newItem))
        {
            todoListBox.Items.Add(newItem);
            newItemTextBox.Clear();
        }
        else
        {
            MessageBox.Show("Please enter a valid to-do item.", "Invalid Input", MessageBoxButtons.OK, MessageBoxIcon.Warning);
        }
    }

    private void removeButton_Click(object sender, EventArgs e)
    {
        if (todoListBox.SelectedItem != null)
        {
            todoListBox.Items.Remove(todoListBox.SelectedItem);
        }
        else
        {
            MessageBox.Show("Please select an item to remove.", "No Selection", MessageBoxButtons.OK, MessageBoxIcon.Warning);
        }
    }

    private void Form1_Load(object sender, EventArgs e)
    {
        // Sample data (optional)
        todoListBox.Items.Add("Sample Task 1");
        todoListBox.Items.Add("Sample Task 2");
    }
}

Conclusion

By following this guide, you have built a simple to-do list application using C# and Windows Forms. This project helps you understand the basics of C# GUI programming, event handling, and working with controls. You can further enhance this application by adding features like saving tasks to a file, setting task priorities, or implementing a search function. Happy coding!

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