Helptopic and .chm files

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Logan Grim

Mar 14, 2014, 3:38:57 PM3/14/14
Dear all,

I have made a number of functions in excel.dna and I am trying to add a help file.

I created a .chm file, gave it an index (1001) and linked it as follows below

<ExcelFunction(Category:="Steam Transport", Description:="Surface Tension of saturated Steam and Water", HelpTopic:="C:\\Users\Logan\Desktop\VB.Net Test\Help\Steam Tables Help.chm!1001", IsMacroType:=True, IsVolatile:=True)>

If I change the reference to anything other than the !1001 then excel tells me that it is an invalid reference. With !1001 I click on the help and nothing happens (no popup but no .chm either)

I know that sometimes these things are picky about having spaces and periods in the filepath so I copied the file to 

  <ExcelFunction(Category:="Steam Transport", Description:="Surface Tension of saturated Steam and Water", HelpTopic:="C:\\SteamTablesHelp.chm!1001", IsMacroType:=True, IsVolatile:=True)>

but the same thing happens

I tried replacing the .chm with a web page

 <ExcelFunction(Category:="Steam Transport", Description:="Surface Tension of saturated Steam and Water", HelpTopic:="", IsMacroType:=True, IsVolatile:=True)>

and this works fine.

Is this something wrong with my machine or am I doing something wrong?



Govert van Drimmelen

Mar 14, 2014, 3:59:59 PM3/14/14
Hi Logan,

What tool are you using to make the help file?
Are you sure the topic is being set up correctly?

These discussions seem to indicate that it can be made to work:

And the ExcelDnaDoc project here:


Logan Grim

Mar 20, 2014, 6:05:59 PM3/20/14
Hi Govert,

Thanks for getting back to me on this, I was using HTML help workshop but if there is a different program that people prefer here I will gladly switch. 

I seem to be having the same issue that harleybl had and since he seems to have solved it I will persevere and try to figure out what is going wrong.



Harley Blumenfeld

Mar 21, 2014, 9:27:38 AM3/21/14
My main problem was that I was experimenting with 1 method that did not work and it seemed to be breaking all Help topics. 
The thing I was trying was to use a file:// URI and that did not work.

What I eventually wound up doing was just putting my chm file in the same directory as the my XLL fine and then just using a relative path.
ExcelDna automatically uses this as the root path if the path to the help file is not rooted during registration.
For me that was the simplest solution since I have an installer that installs the Add-in on the user's desktops.
In this regard my annotations look like this:

[ExcelFunction(Name="Foo", HelpTopic="MyHelp.chm!1")]
public static object Foo( double a, double b, double c)

zion Bee

Jun 13, 2014, 1:17:58 AM6/13/14
I met the same problem too.
And it works with another .chm file.
it is just because the .chm file has no content index of 1001.
And it does not work if you don't give [!] + [number] after *.chm

Worked example:

Failed example:
HelpTopic:="TestHelp.chm"              no ! + number
HelpTopic:="TestHelp.chm!99999999"              bad index :99999999

在 2014年3月21日星期五UTC+9下午10时27分38秒,Harley Blumenfeld写道:


Aug 11, 2021, 12:23:42 PMAug 11
to Excel-DNA
Is there really no way to pull up html files via file:// as it Excel does for http:/ links? 
Or alternatively, are there possibilities to create clickable links with Description?

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