Creating a WinForms Project
Go to File → New → Project and select Windows Forms App (.NET). Visual Studio creates a solution with Form1.cs (code), Form1.Designer.cs (auto-generated layout), and Program.cs (entry point).
WinForms entry point
Program.cs
// Program.cs — WinForms entry point ApplicationConfiguration.Initialize(); Application.Run(new Form1());
The Form Designer
Double-click Form1.cs to open the Design view. Open the Toolbox (View → Toolbox) and drag controls—Button, TextBox, Label, etc.—onto the form. Use the Properties panel to change names, text, colours, and fonts.
Setting Form Properties
The most important Form properties: Text (title bar caption), Size, FormBorderStyle, StartPosition, BackColor, and Icon. Set MaximizeBox = false to prevent resizing.
Form setup code
FormSetup.cs
// In Form1 constructor (or Form1.Designer.cs) this.Text = "My First WinForms App"; this.Size = new Size(600, 400); this.StartPosition = FormStartPosition.CenterScreen; this.BackColor = Color.FromArgb(15, 15, 30); this.FormBorderStyle = FormBorderStyle.FixedSingle; this.MaximizeBox = false;
A Complete Mini App
Let's build a temperature converter. Drag a Label, a TextBox, two RadioButtons, and a Button onto the form. Double-click the button to generate a Click event handler.
Temperature converter
TempConverter.cs
private void btnConvert_Click(object sender, EventArgs e)
{
if (!double.TryParse(txtInput.Text, out double val))
{
lblResult.Text = "Please enter a valid number.";
return;
}
double result = rbCtoF.Checked
? val * 9 / 5 + 32
: (val - 32) * 5 / 9;
string from = rbCtoF.Checked ? "°C" : "°F";
string to = rbCtoF.Checked ? "°F" : "°C";
lblResult.Text = $"{val}{from} = {result:F2}{to}";
}