.Net中虽然类库很强的，但还是有些时候功能有限，掌握常用的api函数，会给我们解决问题提供另一种思路，下面给出自己常用到的Api函数，以备查询。
知道api函数，但却不知道c#或VB.net该如何声明，可以查询这个网站：http://pinvoke.net/
1，SetForegroundWindow
将窗口显示到最前面，前提是窗口没有最小化。
[DllImport("User32.dll")]
public static extern bool SetForegroundWindow(IntPtr hWnd);
2，ShowWindowAsync
显示窗口，如最小化后显示正常，这是异步的。
[DllImport("User32.dll")]
public static extern bool ShowWindowAsync(IntPtr hWnd, int cmdShow);
public enum ShowState : int
{
SW_HIDE = 0,
SW_SHOWNORMAL = 1,
SW_NORMAL = 1,
SW_SHOWMINIMIZED = 2,
SW_SHOWMAXIMIZED = 3,
SW_MAXIMIZE = 3,
SW_SHOWNOACTIVATE = 4,
SW_SHOW = 5,
SW_MINIMIZE = 6,
SW_SHOWMINNOACTIVE = 7,
SW_SHOWNA = 8,
SW_RESTORE = 9,
SW_SHOWDEFAULT = 10,
SW_FORCEMINIMIZE = 11,
SW_MAX = 11
}
3，SendMessage
进程间通信，接受窗口要有消息循环才行。WM_COPYDATA
public const int WM_COPYDATA = 0x004A;
public struct COPYDATASTRUCT
{
public IntPtr dwData;
public int cbData;
[MarshalAs(UnmanagedType.LPStr)]
public string lpData;
}
[DllImport("User32.dll", EntryPoint = "SendMessage")]
public static extern int SendMessage(
IntPtr hWnd, // handle to destination window
int Msg, // message
int wParam, // first message parameter
ref COPYDATASTRUCT lParam // second message parameter
);
例子：
发送方：
byte[] sarr = System.Text.Encoding.Default.GetBytes(args[0]);
Winn32.COPYDATASTRUCT copyData = new Winn32.COPYDATASTRUCT();
copyData.cbData = sarr.Length + 1;
copyData.lpData = args[0];
copyData.dwData = (IntPtr)100; //这里随便写什么数字
Winn32.SendMessage(runningInstance.MainWindowHandle, Winn32.WM_COPYDATA, 0, ref copyData);
接收方
protected override void DefWndProc(ref Message m)
{
if (m.Msg == Winn32.WM_COPYDATA)
{
Winn32.COPYDATASTRUCT copyData = new Winn32.COPYDATASTRUCT();
Type type = copyData.GetType();
copyData = (Winn32.COPYDATASTRUCT)m.GetLParam(type);
this.textBox1.Text = copyData.lpData;
}
base.DefWndProc(ref m);
}
4，FindWindow
找到窗口句柄
[DllImport("User32.dll", EntryPoint = "FindWindow")]
private static extern int FindWindow(string lpClassName, string lpWindowName);
5，SetLocalTime
设定系统时间
[StructLayout(LayoutKind.Sequential)]
public struct SYSTEMTIME
{
public ushort wYear;
public ushort wMonth;
public ushort wDayOfWeek;
public ushort wDay;
public ushort wHour;
public ushort wMinute;
public ushort wSecond;
public ushort wMilliseconds;
public void FromDateTime(DateTime dateTime)
{
wYear = (ushort)dateTime.Year;
wMonth = (ushort)dateTime.Month;
wDayOfWeek = (ushort)dateTime.DayOfWeek;
wDay = (ushort)dateTime.Day;
wHour = (ushort)dateTime.Hour;
wMinute = (ushort)dateTime.Minute;
wSecond = (ushort)dateTime.Second;
wMilliseconds = (ushort)dateTime.Millisecond;
}
public DateTime ToDateTime()
{
return new DateTime(wYear, wMonth, wDay, wHour, wMinute, wSecond);
}
}
[DllImport("kernel32.dll")]
public static extern bool SetLocalTime(ref SYSTEMTIME Time);
6，SHGetFileInfo
获取执行文件的图标icon
[Flags]
enum SHGFI : int
{
/// <summary>get icon</summary>
Icon = 0x000000100,
/// <summary>get display name</summary>
DisplayName = 0x000000200,
/// <summary>get type name</summary>
TypeName = 0x000000400,
/// <summary>get attributes</summary>
Attributes = 0x000000800,
/// <summary>get icon location</summary>
IconLocation = 0x000001000,
/// <summary>return exe type</summary>
ExeType = 0x000002000,
/// <summary>get system icon index</summary>
SysIconIndex = 0x000004000,
/// <summary>put a link overlay on icon</summary>
LinkOverlay = 0x000008000,
/// <summary>show icon in selected state</summary>
Selected = 0x000010000,
/// <summary>get only specified attributes</summary>
Attr_Specified = 0x000020000,
/// <summary>get large icon</summary>
LargeIcon = 0x000000000,
/// <summary>get small icon</summary>
SmallIcon = 0x000000001,
/// <summary>get open icon</summary>
OpenIcon = 0x000000002,
/// <summary>get shell size icon</summary>
ShellIconSize = 0x000000004,
/// <summary>pszPath is a pidl</summary>
PIDL = 0x000000008,
/// <summary>use passed dwFileAttribute</summary>
UseFileAttributes = 0x000000010,
/// <summary>apply the appropriate overlays</summary>
AddOverlays = 0x000000020,
/// <summary>Get the index of the overlay in the upper 8 bits of the iIcon</summary>
OverlayIndex = 0x000000040,
}
[StructLayout(LayoutKind.Sequential, CharSet = CharSet.Auto)]
public struct SHFILEINFO
{
public SHFILEINFO(bool b)
{
hIcon = IntPtr.Zero;
iIcon = 0;
dwAttributes = 0;
szDisplayName = "";
szTypeName = "";
}
public IntPtr hIcon;
public int iIcon;
public uint dwAttributes;
[MarshalAs(UnmanagedType.ByValTStr, SizeConst = 260)]
public string szDisplayName;
[MarshalAs(UnmanagedType.ByValTStr, SizeConst = 80)]
public string szTypeName;
};
[DllImport("shell32.dll", CharSet = CharSet.Unicode)]//路径有中文字符，要用unicode
public static extern int SHGetFileInfo(
string pszPath,
int dwFileAttributes,
out SHFILEINFO psfi,
uint cbfileInfo,
SHGFI uFlags);
例子：
private static Icon GetIcon(string strPath, bool bSmall)
{
SHFILEINFO info = new SHFILEINFO(true);
int cbFileInfo = Marshal.SizeOf(info);
SHGFI flags;
if (bSmall)
flags = SHGFI.Icon | SHGFI.SmallIcon | SHGFI.UseFileAttributes;
else
flags = SHGFI.Icon | SHGFI.LargeIcon;
Win32API.SHGetFileInfo(strPath, 256, out info, (uint)cbFileInfo, flags);
return Icon.FromHandle(info.hIcon);
}
7，GetWindowThreadProcessId
得到句柄的进程和线程ID，返回的是线程ID，ref返回的是进程ID
[System.Runtime.InteropServices.DllImport("User32.dll")]
private static extern int GetWindowThreadProcessId(int Hwnd, ref int OutPressId);
例子：杀死excel进程
int processID = 0;
int threadID;
threadID = GetWindowThreadProcessId(excelApp.Hwnd, ref processID);
if (processID > 0)
{
System.Diagnostics.Process process = System.Diagnostics.Process.GetProcessById(processID);
if (process != null)
{
process.Kill();
}
}