How to decide a Type is a custom struct?

Question

For a Type, there is a property IsClass in C#, but how to decide a Type is a struct?

Although IsValueType is a ne

Answer 1

You're going to have a tough time with this. The base Framework doesn't know what all the predefined types in other parts of the Framework are. It's unreasonable to expect the core Framework to know about System.Drawing.Point, for example.

OregonGhost has probably the best answer: get the type info and check the FullName property to see if it starts with "System.". But you'll also need to check for "Microsoft." and "FSharp", and possibly others. Just click on "Add a reference" in Visual Studio, and see what names come up.

And then you might risk blocking too much. Microsoft distributes some assemblies via NuGet packages, and the types in those assemblies often have names that start with "System." or "Microsoft." Do you consider those "Built in" types even though they're not distributed with the Framework?

Answer 2

http://msdn.microsoft.com/en-us/library/bfft1t3c.aspx says: IsValueType is true if Type is in {bool, byte, char, decimal, double, enum, float, int, long, sbyte, short, struct, uint, ulong, ushort}.

http://msdn.microsoft.com/en-us/library/system.type.isprimitive%28v=vs.110%29.aspx says: IsPrimitive is true if Type is in {Boolean, Byte, SByte, Int16, UInt16, Int32, UInt32, Int64, UInt64, IntPtr, UIntPtr, Char, Double, and Single}.

Than for IsStruct you can use method like this:

public static bool IsStruct(this Type type)
{
    return type.IsValueType 
            && !type.IsPrimitive 
            && !type.IsEnum 
            && type != typeof(decimal);
}

Answer 3

Should be at least

bool isStruct = type.IsValueType && !type.IsEnum &&
               !type.IsPrimitive && type != typeof(decimal);

Answer 4

It worked for me !x.PropertyType.IsSecurityTransparent && x.PropertyType.IsClass

Answer 5

Technically, an int is also a struct. IsPrimitive just checks if the type is one of the primitive types the CLR handles a little differently. You should be fine with the suggestion IsValueType && !IsEnum && !IsPrimitive.

If you want only custom structs (i.e. those not supplied by the BCL), you may have luck excluding types with a FullName that starts with "System.", or only including the ones you're interested in by filtering by assembly or namespace, or use a custom attribute.

Answer 6

Not a perfect solution, but you can always consider narrowing the search by known types within the assemblies you wish to search:

System.Reflection.Assembly.GetAssembly(tyepof(OneOfMyTypes))
    .GetExportedTypes()
    .Where(t => t.IsValueType);

The helps eliminate false positives (safer?), but it's less portable.