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VB.NET IntPtr.Zero字段代码示例

本文整理汇总了VB.NET中System.IntPtr.Zero字段的典型用法代码示例。如果您正苦于以下问题:VB.NET IntPtr.Zero字段的具体用法?VB.NET IntPtr.Zero怎么用?VB.NET IntPtr.Zero使用的例子?那么恭喜您, 这里精选的字段代码示例或许可以为您提供帮助。您也可以进一步了解该字段所在System.IntPtr的用法示例。


在下文中一共展示了IntPtr.Zero字段的2个代码示例,这些例子默认根据受欢迎程度排序。您可以为喜欢或者感觉有用的代码点赞,您的评价将有助于系统推荐出更棒的VB.NET代码示例。

示例1: Example

' 导入命名空间
Imports Microsoft.Win32.SafeHandles
Imports System.Runtime.InteropServices

Module Example
   Private Const GENERIC_READ As UInteger = 2147483648
   Private Const OPEN_EXISTING As UInteger = 3 
   Private Const FILE_ATTRIBUTE_NORMAL As UInteger = 128
   Private Const FILE_FLAG_OVERLAPPED As UInteger = &h40000000

   Private Declare Auto Function CreateFile Lib "Kernel32" Alias "CreateFileW" (
            lpFileName As String, dwDesiredAccess As UInt32, 
            dwShareMode As UInt32, pSecurityAttributes As IntPtr, 
            dwCreationDisposition As UInt32, dwFlagsAndAttributes As UInt32, 
            hTemplateFile As IntPtr) As SafeFileHandle

   Public Sub Main()
      Dim hnd As SafeFileHandle = CreateFile("CallOfTheWild.txt", GENERIC_READ, 0, 
                                             IntPtr.Zero, OPEN_EXISTING,
                                             FILE_ATTRIBUTE_NORMAL Or FILE_FLAG_OVERLAPPED, 
                                             IntPtr.Zero)
      If hnd.IsInvalid Then
         Dim ex As Exception = Marshal.GetExceptionForHR(Marshal.GetHRForLastWin32Error())
         Console.WriteLine("Attempt to open file failed:")
         Console.WriteLine("  {0}", ex.Message)
         Return           
      Else 
         Console.WriteLine("File successfully opened.")
         hnd.Close()     
      End If
   End Sub
End Module
开发者ID:VB.NET开发者,项目名称:System,代码行数:32,代码来源:IntPtr.Zero

输出:

Attempt to open file failed:
The system cannot find the file specified. (Exception from HRESULT: 0x80070002)

示例2: Example

Module Example
   Private Const GW_OWNER As Integer = 4

   Private Declare Function GetWindow Lib "user32" (hWnd As IntPtr, 
                            wFlag As Integer) As IntPtr 

   Public Sub Main()
      Dim hwnd = new IntPtr(3)
      Dim hOwner As IntPtr = GetWindow(hwnd, GW_OWNER)
      If hOwner = IntPtr.Zero Then
         Console.WriteLine("Window not found.")
      End If   
   End Sub
End Module
开发者ID:VB.NET开发者,项目名称:System,代码行数:14,代码来源:IntPtr.Zero

输出:

Window not found.


注:本文中的System.IntPtr.Zero字段示例由纯净天空整理自Github/MSDocs等开源代码及文档管理平台,相关代码片段筛选自各路编程大神贡献的开源项目,源码版权归原作者所有,传播和使用请参考对应项目的License;未经允许,请勿转载。