How to iterate through each property of a custom vb.net object?

Question

How can I go through each of the properties in my custom object? It is not a collection object, but is there something like this for non-collection objects?

For Each entry as String in myObject
    ' Do stuff here...
Next

There are string, integer and boolean properties in my object.

score 68 · Accepted Answer · edited Nov 24 '08 at 15:18

68

By using reflection you can do that. In C# it looks like that;

PropertyInfo[] propertyInfo = myobject.GetType().GetProperties();

Added a VB.Net translation:

Dim info() As PropertyInfo = myobject.GetType().GetProperties()

edited Nov 24 '08 at 15:18

Joel Coehoorn

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answered Nov 24 '08 at 15:15

Ali Ersöz

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Where is the value inside each entry? – Anders Nov 24 '08 at 16:10
There is a method named propertyInfo.GetValue(). – Ali Ersöz Nov 25 '08 at 10:43
How does this work in the context of a `For Each` loop? – tmsimont Jan 27 '14 at 20:25
1

@tmsimont You would loop through the array propertyInfo ie. `For Each i in propertyInfo //Do stuff Next` – dherrin79 Jan 30 '14 at 22:36

Mehrdad Afshari · Answer 2 · 2008-11-24T15:27:20.620

45

You can use System.Reflection namespace to query information about the object type.

For Each p As System.Reflection.PropertyInfo In obj.GetType().GetProperties()
   If p.CanRead Then
       Console.WriteLine("{0}: {1}", p.Name, p.GetValue(obj, Nothing))
   End If
Next

Please note that it is not suggested to use this approach instead of collections in your code. Reflection is a performance intensive thing and should be used wisely.

edited Nov 24 '08 at 15:27

answered Nov 24 '08 at 15:22

Mehrdad Afshari

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I had a problem. it's error : Object reference not set to an instance of an object. – Fame th Jun 17 '16 at 05:13

score 7 · Answer 3 · answered Nov 17 '11 at 12:35

System.Reflection is "heavy-weight", i always implement a lighter method first..

//C#

if (item is IEnumerable) {
    foreach (object o in item as IEnumerable) {
            //do function
    }
} else {
    foreach (System.Reflection.PropertyInfo p in obj.GetType().GetProperties())      {
        if (p.CanRead) {
            Console.WriteLine("{0}: {1}", p.Name, p.GetValue(obj,  null)); //possible function
        }
    }
}

'VB.Net

  If TypeOf item Is IEnumerable Then

    For Each o As Object In TryCast(item, IEnumerable)
               'Do Function
     Next
  Else
    For Each p As System.Reflection.PropertyInfo In obj.GetType().GetProperties()
         If p.CanRead Then
               Console.WriteLine("{0}: {1}", p.Name, p.GetValue(obj, Nothing))  'possible function
          End If
      Next
  End If

score 1 · Answer 4 · answered Nov 24 '08 at 15:16

You can use reflection... With Reflection you can examine every member of a class (a Type), proeprties, methods, contructors, fields, etc..

using System.Reflection;

Type type = job.GetType();
    foreach ( MemberInfo memInfo in type.GetMembers() )
       if (memInfo is PropertyInfo)
       {
            // Do Something
       }

How to iterate through each property of a custom vb.net object?

4 Answers4

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