RegisterHotKey(....) to disable hotkeys such as ALT+F4 is not working in C# Web Browser control

Question

Disabling hot keys like "ALT+F4" using register RegisterHotKey(..) function and wndproc(..) function in c# windows application is not working as expected in few cases. Below is the description.
I am using C# Web Browser control in windows application to display Web Pages. We are disabling hot keys like ALT+F4 by calling the method RegisterHotKey(..) and capture the hot key message in Wndproc(..) function. Initially This is working as expected
normally.
But as part of new requirement, we need to set the "title of Web browser page" to its parent class(Win form) text property. when we are assigning text property of winform using below code, the hot keys could not be disabled.
this.Text = webBrowserCustom.DocumentTitle; //this keyword refers to WinForm which loads web browser control
If webBrowserCustom.DocumentTitle is empty then this.text is set to Empty string. In such case the hot keys are not getting disabled.
I am not sure what is the relation between text property of winform and hot keys disabling.
Could you please let us know why hot keys are not getting disabled when we setting empty string to Winform(which is loading Web Browser control) text property.?

Answer 1

Hi,
How did you use RegisterHotKey and winproc function in your project, could you please post the code here so that we can reproduce the problem firstly?
If you just want to prevent the user from closing the form, you could register Form_Closing event handler, and cancel the closing behavior by the user. 
private void Form1_FormClosing(object sender, FormClosingEventArgs e)
e.Cancel = (e.CloseReason == CloseReason.UserClosing);
private void btnCloseForm_Click(object sender, EventArgs e)
this.FormClosing -= new System.Windows.Forms.FormClosingEventHandler(this.Form1_FormClosing);
this.Close();
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