How C # implements a hang lock

You first set up an instance of a subform in the main form, and then when you click Hang, the current form is hidden and the subform is displayed.

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The background form of the handle form set the following properties (mainly the background is changed to a picture, and then FormBorderStyle to none, you can implement a borderless form), and the default is to maximize the start, so you can think of a picture is covered with the entire window

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This way, unless the user entered the correct password, or will not be able to quit the current program, I put the text box and button just sit on the Baidu page above, this can be a genuine, of course, this page is a picture, in addition to this button can point and this text box can be entered, nothing else to do. I changed the font of the text box with Baidu is not the same, so you can confirm that Baidu is not true.

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To be more secure, such as preventing users from entering Ctrl+a/t+del into the task Manager to kill the process of your software, you can use the keyboard hooks to block these deviant behavior. And if the user restarts, you can also set the boot automatically run.

How C # implements a hang lock