在另一个项目中引用枚举

Question

I have the following code in project1 that is calling a class from project2.

Project1 is calling: ConvertDocument.Convert(CommandLineFile, "d:\\testing\\test.pdf", WdSaveFormat.wdFormatPDF );

Project 2 contains ConvertDocument and WdSaveFormat is from Microsoft.Office.Interop.Word that is referenced in project2.

When I try to pass the enum value to project2 with the above code, it gives me:

Cannot resolve symbol "WdSaveFormat".

My question is, can I reference that enum in project2 that is referencing Microsoft.Office.Interop.Word from Project1 without having to add the reference?

I hope that makes sense...

Thanks again!

Answer 1

No, Project 1 will need a reference to Microsoft.Office.Interop.Word.

The only way around this is to have Project 2 accept an object (or in the case, an int would be better), rather than WdSaveFormat. (Edit: or as other commenters point out, Project 2 could define its own enum that maps back to WdSaveFormat). Project 2 can then cast the int to the WdSaveFormat enum.

For example:

void Convert(string in, string out, int saveFormat)
{
    WdSaveFormat wdSaveFormat = (WdSaveFormat) saveFormat;
}

However, when you try to run this piece of code in Project 1, the runtime will still need to be able to locate a copy of the Microsoft.Office.Interop.Word dll anyway.

Answer 2

The best solution is to create your own type to marshal parameters between libraries and projects.

Do NOT require communications between projects to know about 3rd party libraries (unless they will always be tightly coupled in this manner). It is much better to create your own types to marshal between project libraries. Then the receiving project (callee) will translate from your custom type to the 3rd party library type.

In this scenario, Project 1 will use a custom enum known by both project 1 and 2. Project 1 will use this enum to talk with project 2 who will translate it into the correct 3rd party type.

For instance (this is rough pseudocode):

public enum SaveFormat
{
    SaveFormat1 = 0,
    SaveFormat2 = 1
};

namespace MyProject1
...
    public void Save()
    {
        MyProject2.SaveDocument( SaveFormat.SaveFormat1 );        
    }

namespace MyProject2
...
    ...
    public void SaveDocument( SaveFormat format )
    {
        WdFormat localFormat = this.Translate( format );        
        ...
    }

    private WdFormat Translate( SaveFormat format )
    {
        switch( format )
        {
            case SaveFormat1:
                return WDFormat1;
            case SaveFormat2:
                return WDFormat2;
            default:
                return WDFormat3;
         }
    }

Answer 3

No, it's not possible. WsSaveFormat is defined in the Word.Interop so, without adding the reference you can't use in project1. However (and keep it clear that I don't recomend it) you could define in your project2 a similar enum and let project1 use that enum. Of course you need a mapping from your enum to Word.Interop enum.

Answer 4

The best rule of thumb I have found when dealing with office interop stuff is: don't export anything that exposes an interop type. The only exposed types should be your types which are wrapping the interop behaviour. As far as I know, this is a good rule of thumb for all third-party code.

Answer 5

No, you have to add reference to the Microsoft.Office.Interop.Word in Project1 one to use an enum defined in the assembly. It wouldn't cost you anything in terms of memory because your Project2 is using the reference anyways (and you are using Project2 in Project1)

Answer 6

No, you're using the enum WdSaveFormat in project 1 so you need a reference to Microsoft.Office.Interop.Word.

If you were consuming a function from project 2 that consumed another dll (eg foo.dll) but didn't explicitly use anything from foo.dll in project 1 then you wouldn't need to have a reference to foo.dll within project 1.