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unregisterclass (user32)

C# Signature:

/// <summary>
/// Unregisters a window class, freeing the memory required for the class.
/// </summary>
/// <param name="lpClassName">
/// Type: LPCTSTR
/// A null-terminated string or a class atom. If lpClassName is a string, it specifies the window class name.
/// This class name must have been registered by a previous call to the RegisterClass or RegisterClassEx function.
/// System classes, such as dialog box controls, cannot be unregistered. If this parameter is an atom,
///   it must be a class atom created by a previous call to the RegisterClass or RegisterClassEx function.
/// The atom must be in the low-order word of lpClassName; the high-order word must be zero.
/// </param>
/// <param name="hInstance">
/// A handle to the instance of the module that created the class.
/// </param>
/// <returns>
/// Type: BOOL
/// If the function succeeds, the return value is nonzero.
/// If the class could not be found or if a window still exists that was created with the class, the return value is zero.
/// To get extended error information, call GetLastError.
/// </returns>
static extern bool UnregisterClass(string lpClassName, IntPtr hInstance);

or use

[DllImport("user32.dll", SetLastError = true)]
public static extern bool UnregisterClass(UInt16 lpClassAtom, IntPtr hInstance);

where lpClassAtom is a class handle returned from RegisterClassEx()

VB.NET Signature:

<DllImport("user32.dll")> _
Private Shared Function UnregisterClass(lpClassName As String, hInstance As IntPtr) As Boolean
End Function

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