Calling a Function with a Structure Parameter


   

/*
A Programmer's Introduction to C# (Second Edition)
by Eric Gunnerson

Publisher: Apress  L.P.
ISBN: 1-893115-62-3
*/

// 31 - InteropCalling Native DLL FunctionsCalling a Function with a Structure Parameter
// copyright 2000 Eric Gunnerson
using System;
using System.Runtime.InteropServices;

struct Point
{
    public int x;
    public int y;
    
    public override string ToString()
    {
        return(String.Format("({0}, {1})", x, y));
    }
}

struct Rect
{
    public int left;
    public int top;
    public int right;
    public int bottom;
    
    public override string ToString()
    {
        return(String.Format("({0}, {1})
    ({2}, {3})", left, top, right, bottom));
    }
}

struct WindowPlacement
{
    public uint length;
    public uint flags;
    public uint showCmd;
    public Point minPosition;
    public Point maxPosition;
    public Rect normalPosition;    
    
    public override string ToString()
    {
        return(String.Format("min, max, normal:
{0}
{1}
{2}",
        minPosition, maxPosition, normalPosition));
    }
}

public class CallingaFunctionwithaStructureParameterWindow
{
    [DllImport("user32")]
    static extern int GetForegroundWindow();
    
    [DllImport("user32")]
    static extern bool GetWindowPlacement(int handle, ref WindowPlacement wp);
    
    public static void Main()
    {
        int window = GetForegroundWindow();
        
        WindowPlacement wp = new WindowPlacement();
        wp.length = (uint) Marshal.SizeOf(wp);
        
        bool result = GetWindowPlacement(window, ref wp);
        
        if (result)
        {
            Console.WriteLine(wp);
        }
    } 
}