Develop Reference

Can the Help.ShowHelp API be modified to simply invoke the CHM file?

This is my primary way for displaying help topics from within my WinForm button click handlers:
Handler:
private void buttonHelp_Click(object sender, EventArgs e)
{
CutTools.DisplayHelpTopic(this, "create-new-viewport.htm");
}
Base method:
public static void DisplayHelpTopic(Control parent, string topic)
{
try
{
// Use an empty form as the parent so that the help file will not block the CAD software
Form mHelpParent = new Form();
// Use location of this DLL file
System.Reflection.Module mod = parent.GetType().Module;
string path = Path.GetDirectoryName(mod.FullyQualifiedName);
Help.ShowHelp(mHelpParent,
Path.Combine(path, "cut-tools-help.chm"), HelpNavigator.Topic, topic);
}
catch (System.Exception ex)
{
_AcAp.Application.ShowAlertDialog(
string.Format("\nError: {0}\nStackTrace: {1}", ex.Message, ex.StackTrace));
}
}
The forms are displaid inside AutoCAD, BricsCAD or ZWCAD. The about is fine and great. But if I want to simply display the CHM file itself (so no actual form is available) I have to do this:
[CommandMethod("TS_DisplayHelp")]
public void TS_DisplayHelp()
{
// Use location of this DLL file
System.Reflection.Module mod = GetType().Module;
System.Diagnostics.Process.Start(
Path.Combine(Path.GetDirectoryName(mod.FullyQualifiedName), "cut-tools-help.chm"));
}
It works but has one drawback. It spawns a new instance of the help and does not use the same instance.
For example:
You start one of the other commands and show the help via button click. You cancel.
You start a different command and show the help via button click. Help.ShowHelp uses same instance.
You can command and start help via TS_DISPLAYHELP and it starts new instance.
Given the context of TS_DISPLAYHELP I can't work out how to directly use Help.ShowHelp as I can in my button click handlers.

At the moment I have managed to get around this issue by duplicating the DisplayHelpTopic code directly in the command TS_DISPLAYHELP method:
[CommandMethod("TS_DisplayHelp")]
public void TS_DisplayHelp()
{
try
{
// Use an empty form as the parent so that the help file will not block the CAD software
Form mHelpParent = new Form();
// Use location of this DLL file
System.Reflection.Module mod = GetType().Module;
string path = Path.GetDirectoryName(mod.FullyQualifiedName);
Help.ShowHelp(mHelpParent,
Path.Combine(path, "cut-tools-help.chm"), HelpNavigator.Topic, "command-index.htm");
}
catch (System.Exception ex)
{
_AcAp.Application.ShowAlertDialog(
string.Format("\nError: {0}\nStackTrace: {1}", ex.Message, ex.StackTrace));
}
}
I know that my default topic is "command-index.htm".
I am happy with the above resolution.

Directx device doesn't initialize for window, Program hang

I've tried following several tutorials an have seem to be having trouble.
I've got an existing program that i'm trying to add a directx window to as an additional popup forum that will run as a child to the main application form.
Here is the windows form class:
public partial class DxWindow : Form
{
Device device;
public DxWindow()
{
InitializeComponent();
initDevice();
}
private void initDevice()
{
MessageBox.Show("hello");
PresentParameters pp = new PresentParameters();
pp.Windowed = true;
pp.SwapEffect = SwapEffect.Discard;
device = new Device(0, DeviceType.Hardware, this, CreateFlags.HardwareVertexProcessing, pp);
}
private void Render()
{
//render stuff
}
private void DxWindow_Paint(object sender, PaintEventArgs e)
{
Render();
}
}
and here is where i initialize the form (from a UI button in main window)
private void toolStripButton3_Click_1(object sender, EventArgs e)
{
if (DirectxWindow == null)
{
DirectxWindow = new DxWindow();
DirectxWindow.Show();
}
}
When i run the program and click the button. it seems create the form in memory but never shows up. when i step through it in the debugger, it gets to "DirectxWindow = new DxWindow();" and then automatically jumps out of break mode and continues running with the main window frozen and no new Dxwindow().
when i break execution is seems to still be on "DirectxWindow = new DxWindow();"
Also, "MessageBox.Show("hello");" in the DxWindow constructor is never called"
Edit: I've deduced that as soon as it hits "PresentParameters pp = new Microsoft.DirectX.Direct3D.PresentParameters();" the application becomes unresponsive without throwing any errors.

Turns out my problem was needing to use
<startup useLegacyV2RuntimeActivationPolicy="true">
in the "App.config" File
Solution was found here: Mixed mode assembly is built against version 'v1.1.4322'
Although i never got the error as described by the OP. i simply had this problem as described in the comments:
"Thank you!!!! This is the weirdest problem I'd ever encountered. In VS 2012 .Net 4.0 my application would just hang the moment I initialized any variable of a type related to this DLL. I'd never seen anything like it. Couldn't find anything about the problem until I found this!" – Quinxy von Besiex

C# ActiveX--how to keep the pops-up dialog(windows.Forms.Form) always on top of browser(IE8)

I have write the ActiveX using C# to communicate with the other browser-based system b, it need pops up an dialog in an other thread because of the existing architecture. the current behavior is that the dialog can be hidden behind if i click the browser title. Is it possible to keep the pops-up dialog always on the top of browser(IE8)? Thanks in advance.
public int operation()
{
....
MyMsgBox myMsgBox = new MyMsgBox(message,title);
evt = System.Threading.AutoResetEvent(false);
Thread showDialogThread = new Thread(ShowMsgDialog);
ShowDislogThread.SetApartmentState(System.Threading.ApartmentState.STA);
showDialogThread.Start(myMsgBox);
System.Threading.WaitHanle.WaitAll(new System.Threading.WaitHandle[] {evt});
....
}
public void ShowMsgDialog(object requestObj)
{
MyMsgBox msgBox = (MyMsgbox)requestObj;
msgBox.showDialog();
evt.Set();
}
Class MyMsgBox:Form
{
public MyMsgBox(string message, string title)
{
//do initialization....
}
}
I have tried to set the TopMost of Form to 'true', then it will be always on the top of all applications. it's not meet the requirement as the pops-up dialog need be only always on the top of browser. Thanks.

I don't think that what you want will be possible.
However, you can make a div stretched across all page and set and event on mouse move to call BringToFront on your ActiveX object. That should do the trick.

Getting error when trying to handle ActiveX event

I have a two ActiveX servers I need to handle it's events.
the first one I got to work with no problems but with the second one I get a error once I try to assign a new event. The one that works the code is below:
public delegate void ICwGetXEvents_OnCommandExEventHandler(uint CommandW, uint CommandL, string CommandText);
public CwGet.CwGetXClass ax_CwGet;
//event
public void CwGetXEvents_OnCommandExEventHandler(uint CommandW, uint CommandL, string CommandText)
{
if (CommandL == 4)
{
//some code
}
}
//ok here is how I assign the controls and event:
ax_CwGet = new CwGetXClass();
ax_CwGet.OnCommandEx += CwGetXEvents_OnCommandExEventHandler;
Ok with the second control(by the way it was created by the same company) I try the same thing:
public delegate void ITrueTtyXEvents_OnCallsignEventHandler(string Call);
public truetty.TrueTtyXClass ax_truetty;
//event
public void TrueTtyXEvents_OnCallsignEventHandler(string Call)
{
//somecode
}
ax_truetty = new TrueTtyXClass();
ax_truetty.OnCallsign+= TrueTtyXEvents_OnCallsignEventHandler;
However when I create the new ActiveX object which works but when I go to assign the event I get this error:
"An outgoing call cannot be made since the application is dispatching an input-synchronous call. (Exception from HRESULT: 0x8001010D (RPC_E_CANTCALLOUT_ININPUTSYNCCALL))"
was wondering if anyone could point me in the right direction..
Mike

This is a threading problem. You should ask the component vendor for help with this, sounds like they didn't set the ThreadingModel registry key properly. But the likely response you'll get is "do not use them from a worker thread, only from an STA thread". Which is very common for ActiveX controls.

How can I make sure only one WPF Window is open at a time?

I have a WPF window that I am launching from inside of a winform app. I only want to allow once instance of that WPF window to be open at a time, and not warn that user if they try to open it again.
I am having a problem however trying to search for that WPF window being open because the window is being launched from a winform. What I normaly do is when searching for a winform, I search for any instances of that winform existing in the Application.Current.OpenForms, and when in WPF I search for Application.Current.Windows
The problem I have is that System.Windows.Application.Current is null when launched from inside of a winform, so I can't search for the WPF window that way. Is there any better way of searching for an existing instance of an open window?
My Code:
if (System.Windows.Application.Current != null)
{
foreach (System.Windows.Window win in System.Windows.Application.Current.Windows)
{
if (win is frmCaseWpf)
{
MessageBox.Show("You may have only one active case open at a time.", "Open Case",
MessageBoxButtons.OK,
MessageBoxIcon.Stop);
win.WindowState = System.Windows.WindowState.Normal;
win.Focus();
win.Activate();
return;
}
}
}

Instead of searching the static application objects, you could instead just track this within your window, with a single static variable. Just keep a variable in the window:
private static frmCaseWpf openWindow = null; // Assuming your class name is frmCaseWpf
When you create a window, either in the initialize routines, or OnLoaded, depending on how you want it to work..:
partial class frmCaseWpf {
public frmCaseWpf {
this.OnLoaded += frmCaseWpf_OnLoaded;
}
private void frmCaseWpf_OnLoaded(object sender, RoutedEventArgs e)
{
if (this.openWindow != null)
{
// Show message box, active this.openWindow, close this
}
this.openWindow = this;
}
}
If you want this window to be reusable, make sure to set this.openWindow = null; when you close the window, as well.

Here's something that's working for me.
private About aboutWin;
private void AboutOpenClicked(object sender, RoutedEventArgs e)
{
if(aboutWin == null)
{
aboutWin = new About();
aboutWin.Closed += (a, b) => aboutWin = null;
aboutWin.Show();
}
else
{
aboutWin.Show();
}
}

It would be better make the frmCaseWpf class a singleton. That way you can't create another instance

Rather than try to search for a Window instance, many people use a session- (or system-) wide "Mutex" or a Mutual Exclusion lock. I was going to rewrite one for you, but I found a good codeproject article demonstrating the technique. It's not complex and very simple.
http://www.codeproject.com/KB/cs/SingleInstanceAppMutex.aspx?msg=2908697
Sneak peek:
[STAThread]
static void Main()
{
bool onlyInstance = false;
Mutex mutex = new Mutex(true, "UniqueApplicationName", out onlyInstance);
if (!onlyInstance) {
return;
}
Application.Run(new MainForm);
GC.KeepAlive(mutex);
}
Hope this helps.
(edit: of course you'll have to modify this slightly for your particular use-case, but it demos the general idea)

I am not really a 'proper' programmer, however I have achieved this in a WPF application (not from a winforms one) by using the following:
Dim wdwDetails As New detailsNew()
Private Sub openNewDetails(ByVal recordID As String)
wdwDetails.Owner = Me
wdwDetails.recordID = recordID
wdwDetails.WindowStartupLocation = Windows.WindowStartupLocation.CenterOwner
wdwDetails.Show()
End Sub
Essentially because I am creating the window object outside of the sub that opens it, there will only be a single window. Any new call to the window open sub will use the same object. But I guess that is what Thomas is referring to also.
Like I said, not sure if this will help you or not though.

You can use XXXwindown.isLoad to check if window is loaded before you create a new window:
if ( !ChildWindow.IsLoaded)
{
childWindow= new ChildWindow();
childWindow.Show();
}