Is it possible to disable the "close" button of a form using C #?

Question

How to disable the button to close the form, as in the image below? (the image below shows the MessageBox window)

MessageBox above was created by me! I want to disable the close button of a regular form.

Answer 1

You are handling the Close event (not a closed event) of the form.

And then you use e.CloseReason to decide whether you want to block it (UserClose) or not (TaskManager Close).

In addition, there is a small example of Disabling the close button in forms on codeproject .

Answer 2

Right-click on the appropriate window and select "Properties". In the "Properties" section, click "Events." Double-click the FormClosing event.

The following code will be created in Windows Form Designer:

 private void myWindow_FormClosing(object sender, FormClosingEventArgs e) { } 

Just update the code to look like this (add e.Cancel = true; ):

 private void myWindow_FormClosing(object sender, FormClosingEventArgs e) { e.Cancel = true; } 

You are done!

Alternatively, if you want to disable the close, maximize and reduce buttons of the window:

You can right-click on the window in question and click on "Properties". In the Properties section, set the ControlBox property to false .

Answer 3

If you work with the MDI child window and disable the close button during window creation, you are excluded (i.e. you want to disable it at a certain time during the life of the form), none of the solutions proposed earlier will work¹.

Instead, we should use the following code:

 [DllImport("user32")] public static extern IntPtr GetSystemMenu(IntPtr hWnd, bool bRevert); [DllImport("user32")] public static extern bool EnableMenuItem(IntPtr hMenu, uint itemId, uint uEnable); public static void DisableCloseButton(this Form form) { // The 1 parameter means to gray out. 0xF060 is SC_CLOSE. EnableMenuItem(GetSystemMenu(form.Handle, false), 0xF060, 1); } public static void EnableCloseButton(this Form form) { // The zero parameter means to enable. 0xF060 is SC_CLOSE. EnableMenuItem(GetSystemMenu(form.Handle, false), 0xF060, 0); } 

¹ You can set ControlBox = false if you do not need any buttons, but this is not what the question asks.

Answer 4

You must override the CreateParams function obtained from System.Windows.Forms.Form

And change the style of the class

 myCp.ClassStyle = 0x200; 

Answer 5

  Closing += (s, eventArgs) => { DialogResult = DialogResult.None; //means that dialog would continue running };