Problem with inserting a picture into Excel sheet in NETLink way

Question

I'm using the NETLink to work with Excel object, there be differences to write code according to the NETLink user manual in Mathematica from C#, but it's hard to do more in fact.

I wanted to put a picture in Excel ActiveSheet, the MSDN gvies notation like this in C#:

public Microsoft.Office.Interop.Excel.Picture Insert (string Filename, object Converter);

first time I trans it as

activesheet@Cells[20, 1]@Select[]
activesheet@Pictures@Insert["E:\\birds.png"]

error ocurred. ... at last, the code was changed to

activesheet@Cells[20, 1]@Select[]    
activesheet@Pictures[]@Insert["E:\\birds.png"]

and it worked. I donot know why paired brackets is necessary for the Pictures? so I hope there be particular Classes browser for NETLink more than the NETTypeInfo function to help understand these objects exactly. If there be Classes browser designed for Assembly when using NETLink would be better?

Answer 1

The crux of the issue is that the symbol WorksheetClass.Pictures is a method, not a property. When using NETLink, methods must always be followed by an argument list, even when no arguments are being specified.

We can distinguish between methods and properties by inspecting the NETTypeInfo:

NETTypeInfo["Microsoft.Office.Interop.Excel.WorksheetClass"]

Here we see that Pictures is a method that takes a single optional index argument.