You can set the several border styles of your windows form. With the help of ‘FormBorderStyle’ property of the windows form, you can control the resizing behavior of the form, you can also control the appearance of the caption bar and buttons controls.
FormBorderStyle has following members:
None : No border.
FixedSingle : A fixed, single-line border.
Fixed3D : A fixed, three-dimensional border.
FixedDialog : A thick, fixed dialog-style border.
Sizable : A resizable border. This is the default border style.
FixedToolWindow A tool window border that is not resizable. A tool window does not appear in the taskbar or in the window that appears when the user presses ALT+TAB. Although forms that specify FixedToolWindow typically are not shown in the taskbar, you must also ensure that the ShowInTaskbar property is set to false, since its default value is true.
SizableToolWindow : A resizable tool window border. A tool window does not appear in the taskbar or in the window that appears when the user presses ALT+TAB.
You can set the FormBorderStyle property through designer property windows or code.
How to set the border style of Windows Forms at design time
In the Properties window, set the FormBorderStyle property to the style you want.
Note: Choosing a border style will control the presence of the Minimize and Maximize boxes on the title bar. To turn their functionality on or off, but leave them present, see the following procedure, “To disable the Minimize and Maximize buttons on Windows Forms.”
How to set the border style of Windows Forms programmatically
Form1.FormBorderStyle = System.Windows.Forms.FormBorderStyle.FixedDialog
Form1.FormBorderStyle = System.Windows.Forms.FormBorderStyle.FixedDialog;