| Author: Patel 04 Dec 2008 | Member Level: Silver | Rating:  Points: 6 |
The implemented solution calls functions inside the user32.dll and kernel32.dll files.
To do this, it is necessary:
To add a reference to the System.Runtime.InteropServices namespace.
To know the name and definition of the function to be called.
To create an extern function using C#.
To make any additional structure to be used in the called functions.
// Step 1
using System.Runtime.InteropServices;
// Steps 2 and 3
[DllImport("User32.dll")]
private static extern bool
GetLastInputInfo(ref LASTINPUTINFO plii);
//Step 4
internal struct LASTINPUTINFO
{
public uint cbSize;
public uint dwTime;
}
When I was trying to make things works, I found an issue with the LASTINPUTINFO structure. I solved the problem by creating a C# struct with the same members as the original function. Note that you need to know the mapping between a Windows data type and the .NET Framework data types. The following table is very useful:
BOOL Boolean variable (should be TRUE or FALSE).
BOOLEAN Boolean variable (should be TRUE or FALSE).
BYTE Byte (8 bits).
CALLBACK Calling convention for callback functions.
CHAR 8-bit Windows (ANSI) character.
COLORREF Red, green, blue (RGB) color value (32 bits).
CONST Variable whose value is to remain constant during execution.
DWORD 32-bit unsigned integer.
DWORD_PTR Unsigned long type for pointer precision. Use when casting a pointer to a long type to perform pointer arithmetic. (Also commonly used for general 32-bit parameters that have been extended to 64 bits in 64-bit Windows.)
INT 32-bit signed integer.
INT_PTR Signed integral type for pointer precision. Use when casting a pointer to an integer to perform pointer arithmetic.
INT32 32-bit signed integer.
INT64 64-bit signed integer.
LONG 32-bit signed integer.
LONG_PTR Signed long type for pointer precision. Use when casting a pointer to a long to perform pointer arithmetic.
LONG32 32-bit signed integer.
LONG64 64-bit signed integer.
LONGLONG 64-bit signed integer.
LPARAM Message parameter.
LPBOOL Pointer to a BOOL.
LPBYTE Pointer to a BYTE.
When using a struct as a parameter, you have to initialize it before it is passed to the function:
LASTINPUTINFO lastInPut = new LASTINPUTINFO();
lastInPut.cbSize = (uint)
System.Runtime.InteropServices.Marshal.SizeOf(lastInPut);
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| Author: Patel 04 Dec 2008 | Member Level: Silver | Rating: Points: 1 |
visit Below Link
http://www.geekpedia.com/tutorial210_Retrieving-the-Operating-System-Idle-Time-Uptime-and-Last-Input-Time.html
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