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Visual Basic 6 definition

Declare Function ClipCursor Lib "user32.dll" (lpRect As RECT) As Long

Visual Basic .NET definition

Declare Function ClipCursor Lib "user32" (ByRef lpRect As Object) As Integer

Description

ClipCursor confines the mouse cursor to a rectangular area of the screen. If the user tries to move the cursor outside of this bounding region or a call to SetCursorPos tells it to go outside the box, the cursor will immediately returned to the area. There is no way to get it out. This bounding effect will last in whatever program you switch to, and will remain even if the program that confined the cursor closes! The only way to "release" the cursor is to "confine" it to the entire screen (see example). It isn't usually a good idea to confine the cursor, since the user expects to move the cursor anywhere (not to mention the disasterous effect if your program quit before releasing the cursor!). ClipCursor Confines the cursor to a rectangular area on the screen. System.Windows.Forms.Cursor.Clip

Return Value

If an error occured, the function returns zero (call GetLastError to get the error code). If successful, the function returns a non-zero value.

Parameters

lpRect The rectangle (in screen coordinates) defining the confinement rectangle.

Further Information:

For further information on Windows API functions such as these, and how to use these API's in your C# and VB.NET applications, please refer to the book 'Network programming in .NET' (Buy at Amazon UK) (Buy at Amazon US)

Visual Basic 6 example source code
' Confine the cursor temporarily to inside of Form1 ' ** Place the following code where you want to confine the cursor. ** Dim r As RECT ' confinement rectangle Dim retval As Long ' return value retval = GetWindowRect(Form1.hWnd, r) ' put window's coordinates into r retval = ClipCursor(r) ' confine the cursor ' ** Place the following code where you want to release the cursor. ** Dim r As RECT, retval As Long Dim deskhWnd As Long ' the handle of the desktop window deskhWnd = GetDesktopWindow() ' get handle of the desktop window retval = GetWindowRect(deskhWnd, r) ' put window's coordinates into r retval = ClipCursor(r) ' "confine" the cursor to the entire screen
C# example source code

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