Develop Reference

Wrapper a dll from some link on the internet

I am trying to wrapper a dll that are in some cloud directory.
private SafeLibraryHandle sevenZipSafeHandle;
public SevenZipHandle(string sevenZipLibPath)
{
this.sevenZipSafeHandle = Kernel32Dll.LoadLibrary(sevenZipLibPath);
if (this.sevenZipSafeHandle.IsInvalid)
{
throw new Win32Exception();
}
}
}
internal static class Kernel32Dll
{
[DllImport("kernel32.dll", CharSet = CharSet.Auto, SetLastError = true)]
internal static extern SafeLibraryHandle LoadLibrary([MarshalAs(UnmanagedType.LPTStr)] string lpFileName);
[DllImport("kernel32.dll", CharSet = CharSet.Ansi, SetLastError = true)]
internal static extern IntPtr GetProcAddress(SafeLibraryHandle hModule, [MarshalAs(UnmanagedType.LPStr)] string procName);
[SuppressUnmanagedCodeSecurity]
[DllImport("kernel32.dll")]
[return: MarshalAs(UnmanagedType.Bool)]
internal static extern bool FreeLibrary(IntPtr hModule);
}
I am validating a dll file, but if I use :
sevenZipLibPath = “c:/temp/file.dll”
it works fine.
But if use some file that is on the internet like:
sevenZipLibPath = “"http://any.blob.core.windows.net/files/file.dll”
it does not work.
How can I check a DLL file from some cloud drive in that situation?

The LoadLibrary function
https://msdn.microsoft.com/en-us/library/windows/desktop/ms684175(v=vs.85).aspx
Only supports filepaths, not urls.
So download it first to a temporary location. You can also do that in code using the webclient class.
A simple example:
https://stackoverflow.com/a/525372/4640588
Edit - Example using the paths you provided
using (WebClient client = new WebClient())
{
client.DownloadFile(
"http://any.blob.core.windows.net/files/file.dll",
"c:/temp/file.dll");
}
Validate it, then delete it afterwards.

How to restore application with the same size?

When I have an application opened and I try to open again it, i want to restore the application launched with the actual size.
The code used is this:
[DllImport("user32.dll")]
[return: MarshalAs(UnmanagedType.Bool)]
private static extern bool SetForegroundWindow(IntPtr hWnd);
[DllImport("user32.dll", CharSet = CharSet.Auto, ExactSpelling = true)]
private static extern int ShowWindow(IntPtr hwnd, int nCmdShow);
private const int SW_SHOW = 5;
public static void SetForegroundMyWindow(IntPtr windowHandle)
{
SetForegroundWindow(windowHandle);
ShowWindow(windowHandle, SW_SHOW);
}
With this code, when the window is maximized, the application is shown with the size without maximize.
Only with SetForegroundWindow, the application is not shown when it is minimized.
What is the way to get my window with the actual size?

Error using c DLL. Attempted to read or write protected memory

I try use a dll created in c in c#, but I get the error "Attempted to read or write protected memory. This is often an indication that other memory is corrupt."
I see very topics here, but i'm not solve the problem. It's possible help me?
My C# code is:
[DllImport("kernel32", SetLastError = true, CharSet = CharSet.Unicode)]
public static extern IntPtr LoadLibrary(string dllToLoad);
[DllImport("kernel32", CharSet = CharSet.Ansi, ExactSpelling = true, SetLastError = true)]
public static extern IntPtr GetProcAddress(IntPtr hModule, string procedureName);
[DllImport("kernel32")]
public static extern bool FreeLibrary(IntPtr hModule);
[DllImport("lib.dll", EntryPoint = "LoadRes", CharSet = CharSet.Ansi, CallingConvention = CallingConvention.Cdecl)]
private static extern SRes LoadRes([MarshalAs(UnmanagedType.LPStr)]string str, bool type);
SRes sres = new SRes();
string path="C:\\123456.fil";
System.IntPtr load = LoadLibrary("lib.dll");
System.IntPtr adress = GetProcAddress(load, "LoadRes");
sres = LoadRes(path, true);
My code to export in c is
__declspec(dllexport) SRes LoadRes( const char *filename, bool header_only );
Thank's for help!!

How to dynamically load and unload a native DLL file?

I have a buggy third-party DLL files that, after some time of execution, starts throwing the access violation exceptions. When that happens I want to reload that DLL file. How do I do that?

Try this
[DllImport("kernel32.dll", CharSet = CharSet.Auto, SetLastError = true)]
private static extern IntPtr LoadLibrary(string libname);
[DllImport("kernel32.dll", CharSet = CharSet.Auto)]
private static extern bool FreeLibrary(IntPtr hModule);
//Load
IntPtr Handle = LoadLibrary(fileName);
if (Handle == IntPtr.Zero)
{
int errorCode = Marshal.GetLastWin32Error();
throw new Exception(string.Format("Failed to load library (ErrorCode: {0})",errorCode));
}
//Free
if(Handle != IntPtr.Zero)
FreeLibrary(Handle);
If you want to call functions first you must create delegate that matches this function and then use WinApi GetProcAddress
[DllImport("kernel32.dll", CharSet = CharSet.Ansi)]
private static extern IntPtr GetProcAddress(IntPtr hModule, string lpProcName);
IntPtr funcaddr = GetProcAddress(Handle,functionName);
YourFunctionDelegate function = Marshal.GetDelegateForFunctionPointer(funcaddr,typeof(YourFunctionDelegate )) as YourFunctionDelegate ;
function.Invoke(pass here your parameters);

Create a worker process that communicates via COM or another IPC mechanism. Then when the DLL dies, you can just restart the worker process.

Load the dll, call it, and then unload it till it's gone.
I've adapted the following code from the VB.Net example here.
[DllImport("powrprof.dll")]
static extern bool IsPwrHibernateAllowed();
[DllImport("kernel32.dll")]
static extern bool FreeLibrary(IntPtr hModule);
[DllImport("kernel32.dll")]
static extern bool LoadLibraryA(string hModule);
[DllImport("kernel32.dll")]
static extern bool GetModuleHandleExA(int dwFlags, string ModuleName, ref IntPtr phModule);
static void Main(string[] args)
{
Console.WriteLine("Is Power Hibernate Allowed? " + DoIsPwrHibernateAllowed());
Console.WriteLine("Press any key to continue...");
Console.ReadKey();
}
private static bool DoIsPwrHibernateAllowed()
{
LoadLibraryA("powrprof.dll");
var result = IsPwrHibernateAllowed();
var hMod = IntPtr.Zero;
if (GetModuleHandleExA(0, "powrprof", ref hMod))
{
while (FreeLibrary(hMod))
{ }
}
return result;
}

bring a console window to front in c#

How can I bring a console application window to front in C# (especially when running the Visual Studio debugger)?

It's hacky, it's horrible, but it works for me (thanks, pinvoke.net!):
using System;
using System.Diagnostics;
using System.Runtime.InteropServices;
using System.Threading;
public class Test
{
[DllImport("user32.dll")]
[return: MarshalAs(UnmanagedType.Bool)]
static extern bool SetForegroundWindow(IntPtr hWnd);
[DllImport("user32.dll", EntryPoint="FindWindow", SetLastError = true)]
static extern IntPtr FindWindowByCaption(IntPtr zeroOnly, string lpWindowName);
public static void Main()
{
string originalTitle = Console.Title;
string uniqueTitle = Guid.NewGuid().ToString();
Console.Title = uniqueTitle;
Thread.Sleep(50);
IntPtr handle = FindWindowByCaption(IntPtr.Zero, uniqueTitle);
if (handle == IntPtr.Zero)
{
Console.WriteLine("Oops, cant find main window.");
return;
}
Console.Title = originalTitle;
while (true)
{
Thread.Sleep(3000);
Console.WriteLine(SetForegroundWindow(handle));
}
}
}

This is what I would do.
[DllImport("kernel32.dll", ExactSpelling = true)]
public static extern IntPtr GetConsoleWindow();
[DllImport("user32.dll")]
[return: MarshalAs(UnmanagedType.Bool)]
public static extern bool SetForegroundWindow(IntPtr hWnd);
public void BringConsoleToFront()
{
SetForegroundWindow(GetConsoleWindow());
}

Get two monitors (at least) and open VisualStudio in the secondary monitor. When you run your app from within VisualStudio it will start up by default on the primary monitor. Since it's the last app to be opened, it starts on top and changing over to VisualStudio doesn't affect it. Works for me anyway.
If you don't already have a second monitor, IMHO, you should.