Why I have already added a .dll to unity, but still can't use it/

I added System.Data.DataSetExtensions.dll to unity’s plugins folder.

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And I found it appear in the reference of ‘assembly-csharp’.

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But I still can’t "using" it.

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How do I use it?

Thanks.

>Solution :

There is no namespace named System.Data.DataSetExtensions, the assembly contains extenion methods, you just need call them with data objects.

An example:

DataTable dt;
foreach(var row in dt.AsEnumerable())
    ....