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Reflection in C# -- want a list of the data types of a class' fields

Answer 1

A:

mi.Name is bringing back want you want, you jsut need to change your COnsole.WriteLine to print it again

ck 2009-07-09 14:14:32

I suspect you might have misunderstood me. I'm wanting a list of the *datatypes*, not the field names. For example, I'm wanting a list [ char[], ushort, char, byte, uint, ulong ], a list that I can use programmatically, and not just display on the screeen.

JaysonFix 2009-07-09 14:22:34

So, in your loop where you're writing them to the console, add the types to a List<Type> using Type.GetType(mi.Name)

ck 2009-07-09 14:49:41

Sorry, instead of mi.Name you want mi.GetType()

ck 2009-07-09 14:50:54

mi.GetType() returns System.Reflection.RtFieldInfo not the actual Type of the field.

Stan R. 2009-07-09 14:55:47

Answer 2

+3 A:

this is how I did it, you want the FieldType which actually returns a Type instance.

var members = typeof(TestMe).GetFields().Select(m => new 
                                         { 
                                             Name = m.Name, 
                                             MemType = m.MemberType, 
                                             RtField = m.GetType(), 
                                             Type = m.FieldType 
                                         });

foreach (var item in members)
    Console.WriteLine("<{0}> <{1}> <{2}> <{3}> {3} {2}", item.MemType, item.RtField, item.Name, item.Type, item.Type, item.Name);

public class TestMe
{
    public string A;
    public int B;
    public byte C;
    public decimal D;
}

This is the output:

<Field> <System.Reflection.RtFieldInfo> <A> <System.String> System.String A 
<Field> <System.Reflection.RtFieldInfo> <B> <System.Int32> System.Int32 B
<Field> <System.Reflection.RtFieldInfo> <C> <System.Byte> System.Byte C
<Field> <System.Reflection.RtFieldInfo> <D> <System.Decimal> System.Decimal D

Stan R. 2009-07-09 14:25:37

Thank you for this idea. I had to modify it a bit to get it to work for me, but the idea came from you -- thanks again. FieldInfo [ ] fieldInfoArray = typeof(MyClass).GetFields() ; List <System.Type> fieldTypeList = new List <System.Type> ( ) ; foreach ( FieldInfo fieldInfo in fieldInfoArray ) fieldTypeList.Add ( fieldInfo.FieldType ) ; foreach ( System.Type type in fieldTypeList ) Console.WriteLine ( type ) ;

JaysonFix 2009-07-09 14:49:54

no problem. btw if you just want a list. you could use the .ToList() method in Linq like so: List<Type> list = typeof(TestMe).GetFields().Select(m => m.FieldType).ToList();

Stan R. 2009-07-09 14:53:33

Answer 3

+1 A:

I'm not sure that MemberInfo has the information you want. You might want to look at GetFields() and the FieldInfo class, or GetProperties() and the PropertyInfo class.

GetMembers() returns all fields, properties and methods, so if your class contained these they would be enumerated as well.

GalacticCowboy 2009-07-09 14:27:49

This is also a good idea ... thank you.

JaysonFix 2009-07-09 14:54:15

Answer 4

A:

You're looking for the Name property off of FieldType, which is available via FieldInfo. You'll need to cast MemberInfo to a FieldInfo first:

foreach (MemberInfo mi in theMemberInfoArray)
{
    if (mi.MemberType == MemberTypes.Field)
    {
        FieldInfo fi = mi as FieldInfo;
        Console.WriteLine(fi.FieldType.Name);
    }
}

Output:

Char[]
UInt16
Char
Byte
UInt32
UInt64

Jeremy Frey 2009-07-09 14:29:24

Thanks! I wish I could accept multiple answers, since your idea is also a good one.

JaysonFix 2009-07-09 14:53:32

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Reflection in C# -- want a list of the data types of a class' fields

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