I am using a legacy DLL and need to marshal some structures for use in
the DLL. For the most part, I have figured out my needs except for one
small item.
I have a structure that contain, among other items, an array of bools
(not BOOL). The array is a fixed size and is contained in the
structure.
Should be simple ie:
[StructLayout(La youtKind.Sequen tial)]
public struct MyArrayStruct2
{
[MarshalAs(Unman agedType.I1)]
public bool flag;
[MarshalAs(Unman agedType.I1)]
public bool flag2;
public int val1;
public int val2;
[MarshalAs(Unman agedType.ByValA rray, ArraySubType =
UnmanagedType.I 1, SizeConst = 9)]
public bool[] bArray;
public BoolArray bArray;
[MarshalAs(Unman agedType.ByValA rray, SizeConst = 3)]
public int[] vals;
}
except when the structure is passed to the DLL, the data after the bool
array is broken and the data. I have found this same issue when the
data alignment in the passed structure is incorrect (ie single bool
type passed without the MarshalAs).
I have found a solution, which involves creating another strucure of
only bool (marshalled) and using the reference to this structure in my
main structure.
[StructLayout(La youtKind.Sequen tial)]
public struct MyArrayStruct2
{
[MarshalAs(Unman agedType.I1)]
public bool flag;
[MarshalAs(Unman agedType.I1)]
public bool flag2;
public int val1;
public int val2;
public BoolArray bArray;
[MarshalAs(Unman agedType.ByValA rray, SizeConst = 3)]
public int[] vals;
}
[StructLayout(La youtKind.Sequen tial)]
public struct BoolArray
{
[MarshalAs(Unman agedType.I1)]
public bool b1;
[MarshalAs(Unman agedType.I1)]
public bool b2;
// more of the same
[MarshalAs(Unman agedType.I1)]
public bool b9;
}
This works fine but is ugly and a bit unwieldy. I have tried different
size and packing attributes for the StructLayout to no avail.
Any ideas? It seems that the ByValArray with the subtype of I1 should
work fine.
Thanks!
GPG
4  6470 
gpg,
Can you show the original structure declaration in C?
--
- Nicholas Paldino [.NET/C# MVP]
- mv*@spam.guard. caspershouse.co m
"gpg" <gp****@hotmail .com> wrote in message
news:11******** *************@i 39g2000cwa.goog legroups.com... I am using a legacy DLL and need to marshal some structures for use in
the DLL. For the most part, I have figured out my needs except for one
small item.
I have a structure that contain, among other items, an array of bools
(not BOOL). The array is a fixed size and is contained in the
structure.
Should be simple ie:
[StructLayout(La youtKind.Sequen tial)]
public struct MyArrayStruct2
{
[MarshalAs(Unman agedType.I1)]
public bool flag;
[MarshalAs(Unman agedType.I1)]
public bool flag2;
public int val1;
public int val2;
[MarshalAs(Unman agedType.ByValA rray, ArraySubType =
UnmanagedType.I 1, SizeConst = 9)]
public bool[] bArray;
public BoolArray bArray;
[MarshalAs(Unman agedType.ByValA rray, SizeConst = 3)]
public int[] vals;
}
except when the structure is passed to the DLL, the data after the bool
array is broken and the data. I have found this same issue when the
data alignment in the passed structure is incorrect (ie single bool
type passed without the MarshalAs).
I have found a solution, which involves creating another strucure of
only bool (marshalled) and using the reference to this structure in my
main structure.
[StructLayout(La youtKind.Sequen tial)]
public struct MyArrayStruct2
{
[MarshalAs(Unman agedType.I1)]
public bool flag;
[MarshalAs(Unman agedType.I1)]
public bool flag2;
public int val1;
public int val2;
public BoolArray bArray;
[MarshalAs(Unman agedType.ByValA rray, SizeConst = 3)]
public int[] vals;
}
[StructLayout(La youtKind.Sequen tial)]
public struct BoolArray
{
[MarshalAs(Unman agedType.I1)]
public bool b1;
[MarshalAs(Unman agedType.I1)]
public bool b2;
// more of the same
[MarshalAs(Unman agedType.I1)]
public bool b9;
}
This works fine but is ugly and a bit unwieldy. I have tried different
size and packing attributes for the StructLayout to no avail.
Any ideas? It seems that the ByValArray with the subtype of I1 should
work fine.
Thanks!
GPG
Here it is along with the function call.
typedef struct _MYARRAYSTRUCT2
{
bool flag;
bool flag2;
long val1;
long val2;
bool bFrequencies[9];
int vals[ 3 ];
} MYARRAYSTRUCT2;
extern "C" PINVOKELIB_API void TestArrayInStru ct2( MYARRAYSTRUCT2*
pStruct );
>Any ideas? It seems that the ByValArray with the subtype of I1 should work fine.
Indeed, but if you can't get it to work, you can try using a byte[]
instead.
Mattias
--
Mattias Sjögren [C# MVP] mattias @ mvps.org http://www.msjogren.net/dotnet/ | http://www.dotnetinterop.com
Please reply only to the newsgroup.
Well ... I have come up with a "sort of" solution to this issue
although I am of the general consesus that this issue is reflective of
a bug of some sort.
On the C# side I have done the following:
public struct MyArrayStruct2
{
[MarshalAs(Unman agedType.I1)]
public bool flag;
[MarshalAs(Unman agedType.I1)]
public bool flag2;
public int val1;
public int val2;
[MarshalAs(Unman agedType.ByValA rray, ArraySubType = UnmanagedType.I 1,
SizeConst = 9)]
public byte[] bArray;
[MarshalAs(Unman agedType.ByValA rray, SizeConst = 3)]
public int[] vals;
}
Notice the change from bool[] to byte[]. Now the consumer initializes
the "bool" array as
myStruct2.bArra y = new byte[9];
for (int i = 0; i < 9; i++)
{
myStruct2.bArra y[i] = Convert.ToByte( false);
}
and we can conversely read the values from the array as
bool bFlag = Convert.ToBoole an(myStruct2.bA rray[i]);
This works with the legacy DLL and everything is happy --- but this is
certainly an awkward and hacky way to perform this.
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