Converting and Calling C++ DLL in C# - C# Discussion Boards

Paint events on container controls

8-Apr-04 4:25

You can P/Invoke the Windows Management APIs and send Windows messages to applications, whether they were written in C/C++, VB, any .NET languages, or practically anything, actually, so long as they use the Windows subsystem. You do this using APIs like FindWindowEx to get an HWND (window handle) to a particular window (you can get the main application handle by enumerating the running processes with Process.GetProcesses then use the Process.MainWindowHandle from each if its a process you want to communicate with). One you get the handle to the control you want (most likely using the Windows class of the window/control), you can use P/Invoke PostMessage or SendMessage to send a Windows message (with the appropriate params) to it.

See the following article for an example and additional links to more information: http://www.codeproject.com/csharp/wmp_pinvoke.asp[^].

Also, read the Platform SDK for more Windows Management API documentation at http://msdn.microsoft.com/library[^].

Microsoft MVP, Visual C#
My Articles

PhilCrompton7-Apr-04 20:49

PhilCrompton

7-Apr-04 20:49

I'm writing a couple of custom controls in the .NET compact framework.

I have two controls, one called "Target" derived from System.Windows.Forms.ContainerControl the other called "Arrow" from System.Windows.Forms.Control. I can successfully add Arrows to the Target's Controls collection.

I have overriden the OnPaint method on both controls and they work correctly as stand-a-long instances. What I want to know is the "correct" way of causing the Paint event of the target to raised the Paint events on each of it's contained arrows.

TIA

Phil

Re: Paint events on container controls

Heath Stewart8-Apr-04 4:19

Converting and Calling C++ DLL in C#

8-Apr-04 4:19

The WM_PAINT Windows message is not typically sent by an application (unless you want to force immediate repainting). It is send by the window manager (Windows in this case) when a window (which includes controls) needs repainting. If you want to force the child controls to repaint, then call the Refresh() method on the instance of your controls.

Microsoft MVP, Visual C#
My Articles

just test

kentou7-Apr-04 20:47

kentou

7-Apr-04 20:47

first time

For the people.For the public.

Re: just test

Dave Kreskowiak8-Apr-04 2:52

Dave Kreskowiak

8-Apr-04 2:52

Yes! CodeProject's posting interface really does work!

RageInTheMachine9532

Vini Deep7-Apr-04 19:23

Vini Deep

7-Apr-04 19:23

Hi,

I am new to C# programming. I want to refer a DLL written in C++ (win32 DLL) in an application in C#. The Dll is in unmanaged code and my tester application is a C# application. I have read somewhere about using tlbimp to generate the metadata file. Can anyone tell me the process or any link which gives me information on this.

Kindly help.

Thanks

Vini

Re: Converting and Calling C++ DLL in C#

Heath Stewart7-Apr-04 19:30

7-Apr-04 19:30

tlbimp.exe only works on COM servers with type libraries (typelibs). If you need to call native APIs that are exported from your DLL, you need to use P/Invoke.

See Interoperating with Unmanaged Code[^] in the .NET Framework SDK for the differences between CCWs, RCWs, and P/Invoke, as well as click "Search comments" above. It's been discussed in this forum more times than you can imagine and there are also MANY articles about both types of interop here on CodeProject and across the 'net.

Microsoft MVP, Visual C#
My Articles

Component based

sreejith ss nair7-Apr-04 18:38

sreejith ss nair

7-Apr-04 18:38

dear there,
i am a c3 programmer and i am new in com based programming. i want to know more about com. is it possible to create reliable COM Components in C# ? Big Grin | :-D

hai, feel free to contact
Sreejith SS Nair

Re: Component based

Heath Stewart7-Apr-04 19:12

Windows Installer condtions problem

7-Apr-04 19:12

Start by reading Nick's article, Creating a CCW for COM-enabled non-.NET Applications[^], and read Exposing .NET Framework Components to COM[^] in the .NET Framework SDK for more detailed information.

Can you create reliable COM components in C#? I don't know, can you? C# is a language, it doesn't create anything - you do. One of the goals of COM is to create a system where language is not so much an end as it is a means. You can write COM components in C++, VB6, and many other languages, as well as languages targeting the CLR (like C#) that make use of the interop services. It is fully supported and one of many viable means to writing COM components. How reliable it is depends on you.

The default shim, mscoree.dll, is also a factor, but I work with a heck of a lot of interop (both CCWs, RCWs, and P/Invoke) and have never had a problem with the shim itself.

Microsoft MVP, Visual C#
My Articles

lieperik7-Apr-04 17:49

lieperik

7-Apr-04 17:49

I got two questions about creating a package using c# & Windows Installer in Visual Studio .NET:

Question 1
I want to enable the user to choose during setup whether he wants to add a shortcut to the desktop or not. I did the following but it does't seem to work:

1. I added a two button RadioButtons dialog box to the Start section (User Interface) to enable the user can select whether he wants or does not want to add a shortcut to the desktop

2. I gave the ButtonProperty the name SELECTSCHORTCUT. If the selection is Yes, the value wil be 1 and if the selection is No the value will be 2

3. In the file File System menu I added a condition for the User's Desktop. The condition is SELECTSHORTCUT = "1"

Can someone tell me what I do wrong?

QUESTION 2

Scenario
1. I go to the User Interace editor and add a two button RadioButtons interface to the Start section (i.e. to enable the user to select whether he want to add a desktop shortcut during installation)

2. Now I want to add one more two buttons RadioButton dialog box to ask whether the user wants to use SQL server or MS Access database. The odd thing is that once I have used a dialog box, I don't seem to be able to add another similar type dialog box the installer. Somehow Visual Studio restricts using two times a RadioButtons Dialog during installation. Why is this and how can I resolve this? I really need to be able to have multple 2 button RadioButtons dialogs during installation

How is able to give an answer on the two problems raised above? Any help is greatly appreciated.

Lieperik

Heath Stewart7-Apr-04 18:16

7-Apr-04 18:16

First, don't use a RadioButton like this: checkboxes are a better alternative (implicitly yes/no controls) and are more common with yes/no questions such as you're using. Using this method, your property is either undefined or null if unchecked, or defined as the constant value you pick if checked. Your condition then merely has to use the property name, like SELECTSHORTCUT. You can still check for the check value, but it's really not required.

Don't add this condition to the Desktop folder, though - it always exists and is assigned when the MSI runtime is loading. Add the condition to your actual shortcut item in the project's File System Editor window.

Finally, regarding your last question: I've been authoring MSI packages since MSI 1.0 beta and am currently on the 3.0 beta team. I've used about every major Windows Installer authoring package and not one is near as bad as those for Visual Studio (especially the add-in for Visual Studio 6 Eek! | :eek:

). the Installer project is not meant to be a commercial deployment solution, however. It's good for deploying internal libraries, samples, and smaller projects from smaller companies. If you want real control, either learn and understand the MSI database and use Orca from the Windows Installer SDK, or look at commercial solutions like Wise Solutions[^] or InstallShield[^]. I personally and professional use the former, since it is much cheaper (and just as capable) and have provided unhindered access to the MSI database before compiling, where InstallShield for Windows Installer didn't add full exposure till version 4.0 (and it's MUCH more expensive).

Microsoft MVP, Visual C#
My Articles

lieperik7-Apr-04 18:55

lieperik

7-Apr-04 18:55

Many thanks for your prompt reply. Your feedback is a great help. One last question if you don't mind:

You noted:
"Don't add this condition to the Desktop folder, though - it always exists and is assigned when the MSI runtime is loading. Add the condition to your actual shortcut item in the project's File System Editor window."

The strange thing is that there is no condition property for the shortcuts (I am using Visual Studio .NET). The only properties shown for the shortcut are: Arguements, Description, Folder, Icon, ShowCmd, Target, Transitive and Working Folder.

Without seeing the propery condition for the shortcut, how can I attached the condition to the shortcut.

Cheers, Lieperik
http://c-sharp.pagina.nl
http://c-sharp.prikpagina.nl

Heath Stewart7-Apr-04 19:05

7-Apr-04 19:05

Yeah, I suppose you're right. I rarely use the Windows Installer projects in VS.NET, sorry.

You can set the condition for the file itself. Files are grouped into Components (guidelines state one executable per component, as well). Components are grouped into Features. Shortcuts are associated with a Component. So, the condition on the file is actually a condition on the Component (files don't have conditions - their components do). Since the shortcut is "tied" to that component, then the component shouldn't installed at all.

The problem is that you only want the shortcut optional, not the component. In this case, you must associate the Shortcut table entry with a new Component that uses this condition, and then associate that Component in the Features table of the MSI package. You can leave the KeyPath field of the Component table record null.

This requires that you install Orca from the Windows Installer SDK, which is part of the Platform SDK[^].

Microsoft MVP, Visual C#
My Articles

lieperik7-Apr-04 19:19

lieperik

7-Apr-04 19:19

Hi Heath,

Thanks again. right now I am downloading the Windows Installer SDK and will install Orca and have a go on that.

Cheers, Lieperik

____________________
http://c-sharp.pagina.nl
http://c-sharp.prikpagina.nl

ComboBox container

DougW487-Apr-04 17:14

DougW48

7-Apr-04 17:14

I declare a ComboBox in a class. The box never actually shows up on a form, but the variable for the box exists, and is initialized. What is confusing me is that I tried setting the datasource and valuemember of this combo box to a table in a dataset, but nothing is being put into the list of my combobox. I'm pretty confused, so some advice or suggestions would help. Thanks! Wink | ;)

Re: ComboBox container

Heath Stewart7-Apr-04 18:20

7-Apr-04 18:20

It doesn't matter if you declare a variable or not, you must add it to the parent control's Controls collection property, just like all the other controls. Expand the "Windows Form Designer generated code" region and look at the InitializeComponent method that the designer code serializer uses for examples, and see the Control.Controls property documentation in the .NET Framework SDK.

Microsoft MVP, Visual C#
My Articles

Re: ComboBox container

DougW487-Apr-04 18:42

DougW48

7-Apr-04 18:42

Excellent help as always. Thanks Heath, worked perfectly. Big Grin | :-D

map network drive

Gardar G7-Apr-04 16:05

Gardar G

7-Apr-04 16:05

Has enyone done this with C#?

regards
GG

Roman Rodov7-Apr-04 17:54

Roman Rodov

7-Apr-04 17:54

Absolutely! Here is what you need to do.

Add these declarations inside your class:

   [StructLayout(LayoutKind.Sequential)]
   private class NETRESOURCE
   {
    public Int32 dwScope;
    public Int32 dwType;
    public Int32 dwDisplayType;
    public Int32 dwUsage;
    public string lpLocalName;
    public string lpRemoteName;
    public string lpComment;
    public string lpProvider;
   }

[DllImport("mpr.dll")]
private static extern Int32 WNetAddConnection2 (
                                NETRESOURCE lpNetResource, 
                                [MarshalAs(UnmanagedType.LPTStr)] string lpPassword, 
                                [MarshalAs(UnmanagedType.LPTStr)] string lpUsername, 
                                Int32 dwFlags);
[DllImport("mpr.dll")]
private static extern Int32 WNetCancelConnection2 (
                                [MarshalAs(UnmanagedType.LPTStr)] string lpResourceName, 
                                [MarshalAs(UnmanagedType.Bool)] bool bForce);

THen Write a function:

void MapShareToDrive(string share, string, localdrive, string username, string password);
{
// Prepare for network access
NETRESOURCE netResource = new NETRESOURCE();
netResource.dwScope = 1;
netResource.dwType = 1;
netResource.lpLocalName = localdrive;
netResource.lpRemoteName = share;
// Connect to network share
int iRetVal = WNetAddConnection2(netResource, password, username, 0);
// You can also do the following to make the system prompt for username/password
// int iRetVal = WNetAddConnection2(netResource, "", "", 24);
if (iRetVal != 0)
{
  throw new System.IO.IOException("Failed to gain access to network share. Error code: " + iRetVal);
}
}

EDIT: Changed marshaling for string parameters to [MarshalAs(UnmanagedType.LPTStr)] .. but anyway my code would work fine on Windows NT and later

Heath Stewart7-Apr-04 18:00

7-Apr-04 18:00

Problem: WNetAddConnectoin2 uses LPCTSTR, or system-dependent string encodings (ANSI for Windows, Unicode for Windows NT). You either need to marshal these as UnmanagedType.LPTStr, or using [DllImport("mpr.dll", EntryPoint="WNetAddConnectoin2A", CharSet=CharSet.Ansi)] to always use the ANSI version of the API exported by mpr.dll on both platforms. The former method is recommend, however. Take advantage of Unicode whenever you can.

Microsoft MVP, Visual C#
My Articles

Gardar G8-Apr-04 15:37

Gardar G

8-Apr-04 15:37

[StructLayout(LayoutKind.Sequential)]
private class NETRESOURCE
{
public Int32 dwScope = 0;
public Int32 dwType = 0;
public Int32 dwDisplayType = 0;
public Int32 dwUsage = 0;
public string lpLocalName = null;
public string lpRemoteName = null;
public string lpComment = null;
public string lpProvider = null;
}

[DllImport("mpr.dll")]
private static extern Int32 WNetAddConnection2
(NETRESOURCE lpNetResource,
[MarshalAs(UnmanagedType.LPTStr)] string lpPassword,
[MarshalAs(UnmanagedType.LPTStr)] string lpUsername,
Int32 dwFlags);
[DllImport("mpr.dll")]
private static extern Int32 WNetCancelConnection2
([MarshalAs(UnmanagedType.LPTStr)] string lpResourceName,
[MarshalAs(UnmanagedType.Bool)] bool bForce);

public void MapShareToDrive(string share, string localdrive, string username, string password)
{ // Prepare for network access
NETRESOURCE netResource = new NETRESOURCE();
netResource.dwScope = 1;
netResource.dwType = 1; //RESOURCETYPE_DISK
netResource.lpLocalName = localdrive;
netResource.lpRemoteName = share;

// Connect to network share
int iRetVal = WNetAddConnection2(netResource, password, username, 8);
// You can also do the following to make the system prompt for username/password
// int iRetVal = WNetAddConnection2(netResource, "", "", 16);
if (iRetVal != 0)
{
throw new System.IO.IOException("Failed to gain access to network share. Error code: " + iRetVal);
}
}

Hi if I used the code example with parameter dwFlags = 0 then I always got error = 5.
If I changed the parameter dwFlags = 8 then the dialog for mapping network prompted?
If I am understanding things right I thought the parameter dwFlags = 16 should prompt the mapping dialog.

Best regards,
Gardar

Heath Stewart7-Apr-04 18:06

7-Apr-04 18:06

Another quick and dirty alternative to Roman's (although I'd prefer that way in production code) is to simply use the Process class to start the net.exe application with the necessary command-line arguments.

For example, barring any requirements for a username and password, you could do it as simply as this:

public void MapDrive(char drive, string path)
{
  Process.Start("net.exe", string.Format("{0}: {1}", drive, path));
}

That's very simplistic and you might want to look at the overloads for Process.Start to hide the console window that would be displayed automatically (in Windows, this is unavoidable; in Windows NT, you can stop the PE loader from displaying the console window for executables using the console subsystem).

Microsoft MVP, Visual C#
My Articles