Creating a new F# project with Excel-DNA and Visual Studio 2019

jant...@gmail.com

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May 7, 2021, 9:24:06 AM5/7/21

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Hi,

I have been using Excel DNA and F# for a while, but I have just "upgraded" to Visual 2019 (from VS2017), and ran into difficulties while creating a new project. I can't get Excel DNA into the project.

I am aware of several articles / resources discussing related issues, e.g. :

[1] resource 1

[2] resource 2

Here are the steps I followed :

1) Using Visual 2019

2) Starting a new F# Class Library (.Net Framework), named Library10 in this example.

3) as recommended by Govert [1], I turned the Options > NuGet Package Manager > General > Package Management "default package manager"

4) This is the original, automatically generated (.fsproject) project file:

</PropertyGroup>

</ItemGroup>

</Project>

At this point I tried to follow Govert's instructions in [2] :

5) Update of the main.fs file :

namespace Library10

module MyFunctions

open ExcelDna.Integration // this is not recognized yet

[<ExcelFunction(Description="My first .NET function")>]

let HelloDna name =

"Hello " + name

(*)

6) I added new properties to the .fsproject file:

</PropertyGroup>

<RunExcelDnaSetDebuggerOptions>false</RunExcelDnaSetDebuggerOptions>

</PropertyGroup>

</ItemGroup>

</Project>

(*)

7) I added a new Library10-Addin.dna file at the solution top-level folder

<?xml version="1.0" encoding="utf-8"?>

</DnaLibrary>

(*)

(*) Finally I tried to load the ExcelDna.AddIn 1.1.1 package via NuGet at several stages, but it never seems to load properly. On the one hand the Nuget Package Manager window indicates that ExcelDna is not loaded. However it does appear under the Solution Explorer.

but the F# does not compile as `open ExcelDna.Integration` isn't recognized.

If you can think of anything that would help me to get out of this painful hole, that'd be great. Thanks in advance.

Jan

Govert van Drimmelen

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May 7, 2021, 4:57:01 PM5/7/21

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Hi Jan,

1. For the Sdk-Style projects, I think the packages.config part does not apply - only PackageReference style is supported.

This means I expect the NuGet reference inside your fsproj file, whether you add it through the UI interface or just edit the project file.

</ItemGroup>

2. Next I think you ended up with a real F# syntax error.

You should not have both the `namespace` and `module` lines.

Try this code without the namespace line:

//////////////////

module MyFunctions

open ExcelDna.Integration

[<ExcelFunction(Description="My first .NET function")>]

let HelloDna name =

"Hello " + name

///////////////

3. My debugger is set up like this for my 64-bit Excel:

Launch: Executable

Executable: C:\Program Files\Microsoft Office\root\Office16\EXCEL.EXE\

Application arguments: FsDna-AddIn64.xll

(Where my project is called FsDna).

Then it works fine for me.

Let me know if you still have trouble.

-Govert

jant...@gmail.com

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May 7, 2021, 9:04:46 PM5/7/21

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Thanks Govert,

The 2) F# error was a typo on my part, which I fixed. But the rest did not seem to fix the issue. It always seems to come from .fsproject file (e.g. I realized the impact of the <IncludeAssets> tag, please see below).

So I recreated another similar project, Library11:

1) I changed .fs file back to our original program

namespace Library11

module MyFunctions =

open ExcelDna.Integration

[<ExcelFunction(Description="My first .NET function")>]

let HelloDna name =

"Hello " + name

2) the original, out-of-the-box, unaltered project .fsproject file is

</PropertyGroup>

</ItemGroup>

</Project>

3) Loading ExcelDna from NuGet

I now have the error message:

Error DNA1546 Excel-DNA is not compatible with projects that use NuGet `PackageReference`. Make sure you create a .NET Framework (Class Library) project and configure Visual Studio to use `packages.config` Library11 C:\Users\W1\.nuget\packages\exceldna.addin\1.1.1\build\ExcelDna.AddIn.targets

while the .fsproject was automatically updated to

</PropertyGroup>

</ItemGroup>

<ItemGroup>

<PackageReference Include="ExcelDna.AddIn" Version="1.1.1">

<PrivateAssets>all</PrivateAssets>

<IncludeAssets>runtime; build; native; contentfiles; analyzers; buildtransitive</IncludeAssets>

</PackageReference>

</ItemGroup>

</Project>

(added lines in bold-face)

4) I then manually edited the .fsproject file to allow Package references.

</PropertyGroup>

<PropertyGroup>

<ExcelDnaAllowPackageReferenceProjectStyle>true</ExcelDnaAllowPackageReferenceProjectStyle>

<RunExcelDnaSetDebuggerOptions>false</RunExcelDnaSetDebuggerOptions>

</PropertyGroup>

</ItemGroup>

<IncludeAssets>runtime; build; native; contentfiles; analyzers; buildtransitive</IncludeAssets>

</PackageReference>

</ItemGroup>

</Project>

That removed the original error.

But two new other errors appeared:

Error FS0039 The namespace or module 'ExcelDna' is not defined. Library11 C:\Users\W1\source\repos\Library11\Library1.fs

Error FS0039 The type 'ExcelFunction' is not defined. Library11 C:\Users\W1\source\repos\Library11\Library1.fs

5) In order to get rid of these other errors, I manually removed the <IncludeAssets> tags from the .fsproject (I got that trick from you on [2])

</PropertyGroup>

<RunExcelDnaSetDebuggerOptions>false</RunExcelDnaSetDebuggerOptions>

</PropertyGroup>

</ItemGroup>

</PackageReference>

</ItemGroup>

</Project>

6) At this stage the project does compile :

Build started...

1>------ Build started: Project: Library11, Configuration: Debug Any CPU ------

1>Library11 -> C:\Users\W1\source\repos\Library11\bin\Debug\net48\Library11.dll

1>---

1>ExcelDnaBuild: ---

1>---

========== Build: 1 succeeded, 0 failed, 0 up-to-date, 0 skipped ==========

7) However it does not seem to generate any .xll file.

(I am not even trying to start the debugger and open an Excel sheet to test the addin at this stage, it's just that there is apparently no ExcelDna .xll to be found in the project).

What else could it be? Thanks for your help.

Jan

Govert van Drimmelen

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May 8, 2021, 1:36:02 AM5/8/21

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Hi Jan,

The best instructions is at the GitHub issue you pointed to initially:

Document F# support with <PackageReference ...> · Issue #360 · Excel-DNA/ExcelDna (github.com)

You are now missing the .dna file, which is the cue for the Excel-DNA build targets.

My project file for the project FsDna.fsproj looks like this (I don't think net472 vs net48 matters):

</PropertyGroup>

<RunExcelDnaSetDebuggerOptions>false</RunExcelDnaSetDebuggerOptions>

</PropertyGroup>

</ItemGroup>

</ItemGroup>

</Project>

Where my FsDna-AddIn.dna file contains:

</DnaLibrary>

-Govert

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jant...@gmail.com

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May 8, 2021, 2:49:11 AM5/8/21

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Thanks a lot Govert!

Adding the line <None Include="Library11-Addin.dna" /> to the .fsproject file did it. (I could not find a reference to this line in the GitHub issue, but now all is good).