GWL_STYLE用于基本窗口样式.你可以阅读他们here.

GWL_EXSTYLE用于扩展窗口样式.你可以阅读他们here.

Imports System.Diagnostics
Imports System.Runtime.InteropServices
 
Module Module1
 
    Sub Main()
       Dim notepad As Process = Process.GetProcessesByName("notepad")(0)
 
       Dim GWL_STYLE As Int32 = -16
       Dim GWL_EXSTYLE As Int32 = -20
 
       ' MainWindowHandle happens to be the handle of the window you want for notepad.
 
       ' It may not be the handle you want if you try this on a different process.
 
       Dim hWnd As IntPtr = notepad.MainWindowHandle
 
       ' You can examine the current styles using GetWindowLong.
       Dim styles As WindowStyles = GetWindowLong(hWnd,GWL_STYLE)
       Dim exStyles As WindowStyles = GetWindowLong(hWnd,GWL_EXSTYLE)
 
       ' WS_VISIBLE must be used for the window to be selectable.
       Dim newStyles As WindowStyles = WindowStyles.WS_VISIBLE Or WindowStyles.WS_BORDER
 
       SetWindowLong(hWnd,GWL_STYLE,newStyles)
 
       ' If you want to modify the extended styles,use GWL_EXSTYLE
 
       SetWindowLong(hWnd,GWL_EXSTYLE,exStyles)
 
 
    End Sub
 
     _
 Private Function GetWindowLong( _
      ByVal hWnd As IntPtr,_
      ByVal nIndex As Integer) As Integer
    End Function
 
     _
    Private Function SetWindowLong( _
    ByVal hWnd As IntPtr,_
    ByVal nIndex As Integer,_
    ByVal dwNewLong As IntPtr) As Integer
    End Function
 
End Module
 
 _
Public Enum WindowStyles As Long
 
    WS_OVERLAPPED = 0
    WS_POPUP = 2147483648
    WS_CHILD = 1073741824
    WS_MINIMIZE = 536870912
    WS_VISIBLE = 268435456
    WS_DISABLED = 134217728
    WS_CLIPSIBLINGS = 67108864
    WS_CLIPCHILDREN = 33554432
    WS_MAXIMIZE = 16777216
    WS_BORDER = 8388608
    WS_DLGFRAME = 4194304
    WS_VSCROLL = 2097152
    WS_HSCROLL = 1048576
    WS_SYSMENU = 524288
    WS_THICKFRAME = 262144
    WS_GROUP = 131072
    WS_TABSTOP = 65536
 
    WS_MINIMIZEBox = 131072
    WS_MAXIMIZEBox = 65536
 
    WS_CAPTION = WS_BORDER Or WS_DLGFRAME
    WS_TILED = WS_OVERLAPPED
    WS_ICONIC = WS_MINIMIZE
    WS_SIZEBox = WS_THICKFRAME
    WS_TILEDWINDOW = WS_OVERLAPPEDWINDOW
 
    WS_OVERLAPPEDWINDOW = WS_OVERLAPPED Or WS_CAPTION Or WS_SYSMENU Or _
              WS_THICKFRAME Or WS_MINIMIZEBox Or WS_MAXIMIZEBox
    WS_POPUPWINDOW = WS_POPUP Or WS_BORDER Or WS_SYSMENU
    WS_CHILDWINDOW = WS_CHILD
 
    WS_EX_DLGMODALFRAME = 1
    WS_EX_NOPARENTNOTIFY = 4
    WS_EX_TOPMOST = 8
    WS_EX_ACCEPTFILES = 16
    WS_EX_TRANSPARENT = 32
 
    '#If (WINVER >= 400) Then
    WS_EX_MDICHILD = 64
    WS_EX_TOOLWINDOW = 128
    WS_EX_WINDOWEDGE = 256
    WS_EX_CLIENTEDGE = 512
    WS_EX_CONTEXTHELP = 1024
 
    WS_EX_RIGHT = 4096
    WS_EX_LEFT = 0
    WS_EX_RTLREADING = 8192
    WS_EX_LTRREADING = 0
    WS_EX_LEFTSCROLLBAR = 16384
    WS_EX_RIGHTSCROLLBAR = 0
 
    WS_EX_CONTROLPARENT = 65536
    WS_EX_STATICEDGE = 131072
    WS_EX_APPWINDOW = 262144
 
    WS_EX_OVERLAPPEDWINDOW = WS_EX_WINDOWEDGE Or WS_EX_CLIENTEDGE
    WS_EX_PALETTEWINDOW = WS_EX_WINDOWEDGE Or WS_EX_TOOLWINDOW Or WS_EX_TOPMOST
    '#End If
 
    '#If (WIN32WINNT >= 500) Then
    WS_EX_LAYERED = 524288
    '#End If
 
    '#If (WINVER >= 500) Then
    WS_EX_NOINHERITLAYOUT = 1048576 ' Disable inheritence of mirroring by children
    WS_EX_LAYOUTRTL = 4194304 ' Right to left mirroring
    '#End If
 
    '#If (WIN32WINNT >= 500) Then
    WS_EX_COMPOSITED = 33554432
    WS_EX_NOACTIVATE = 67108864
    '#End If
 
End Enum

代码说明

我不确定你在开发GUI应用程序方面有多少经验,所以我将给出窗口如何工作的一些背景知识.窗口具有唯一标识的数字,称为句柄.与窗口相关联的还有一个窗口过程,它处理该窗口的消息(标识事件和命令的整数).创建窗口时,您可以指定窗口所需的样式等等.对于Windows应用程序来说,复杂性要高得多,但为了避免陷入细节,我们将继续前进.

值得庆幸的是,.NET Winforms使我们不必与Windows API进行交互并直接处理消息(大多数情况下),并且可以非常轻松地创建功能性GUI应用程序. Windows API中有很多功能,大多数.NET开发人员通常不需要担心.

现在有了这样的背景,代码应该更容易理解.

首先,我们需要获得名为“notepad”的第一个进程.

Dim notepad As Process = Process.GetProcessesByName("notepad")(0)

然后我们定义两个整数GWL_STYLE和GWL_EXSTYLE.这两个整数在SetWindowLong函数的上下文中具有特定含义.它们的值(以及许多其他常量的值)可以在Winuser.h和Windows SDK中的其余头文件中找到.

Dim GWL_STYLE As Int32 = -16
Dim GWL_EXSTYLE As Int32 = -20

接下来我们得到记事本主窗口的句柄.

Dim hWnd As IntPtr = notepad.MainWindowHandle

之后我们遇到了GetWindowLong功能.来自MSDN：

The GetWindowLong function retrieves information about the specified window.

GetWindowLong获取窗口句柄和一个值,该值指示要检索的信息并返回指定的信息.

Dim styles As WindowStyles = GetWindowLong(hWnd,GWL_STYLE)
Dim exStyles As WindowStyles = GetWindowLong(hWnd,GWL_EXSTYLE)

这些都包括在内,因此您可以看到应用于窗口的样式,因此您可以确定要省略哪些样式.

接下来,我们定义要应用于窗口的样式.你可以阅读各种风格及其含义here.

Dim newStyles As WindowStyles = WindowStyles.WS_VISIBLE Or WindowStyles.WS_BORDER

然后我们使用SetWindowLong将这些样式应用于窗口.来自MSDN：

The SetWindowLong function changes an attribute of the specified window.

SetWindowLong获取窗口句柄,指示要更改的属性的值以及属性的新值,并更改属性.

SetWindowLong(hWnd,newStyles)

这基本上就是代码的作用.为了避免重复,我不会重复使用GWL_EXSTYLE,因为它的使用方式与GWL_STYLE完全相同.其余代码只是物流,允许我们使用SetWindowLong和GetWindowLong.