C # how to pass C + + dll in the char (& content) [500] reference type parameter

content as char [500] array
C # output parameters when calling a DLL how to write ?
I am now writing is (ref Content), in which content is defined as char [] content = new char [500].

now invalid parameter error saying mean
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StringBuilder
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this syntax I do not understand how the latest ?
int getpower (byte (& beam) [10])
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online experts hope to answer
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artificial Sticky
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to hwenycocodq520: Well
Would you elaborate ?
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call dll written in c + +
his header file write extern "c" _declspec (dllimport) int getpower (byte (& beam) [10])
should be how to pass parameters to write ?
parameter write (ref beam) beam as a byte array
reported method type signature is not compatible with the interop error

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problem has been resolved.