VB .NET Access a class property by string value

Question

I have a function that updates a Client in the database. A client object is passed in, along with a string array of fields/properties that should be updated. I need a way of accessing each property in the client object, based on what is in the array. Basically, I am looking for the VB .NET equivalent to this javascript:

var fields = ["Firstname","Lastname","DOB"];
for(field in fields)
{
    var thisField = fields[field];
    client[thisField] = obj[thisField];
}

Any help will be greatly appreciated! Thanks Stack.

Adam Maras · Accepted Answer · 2010-11-16 04:29:36Z

8

You can use Reflection to do this. Without knowing more about how your data objects are set up, I can't give you a perfect example, but here's the general idea:

Dim myPerson As New Person
myPerson.FirstName = "John"
myPerson.LastName  = "Doe"
myPerson.DOB       = #1/1/2000#

Dim myUpdates As New Dictionary(Of String, Object)
myUpdates.Add("FirstName", "Adam")
myUpdates.Add("LastName" , "Maras")
myUpdates.Add("DOB"      , #1/1/1990#)

Dim personType As Type = GetType(Person)

For Each kvp As KeyValuePair(Of String, Object) In myUpdates
    Dim propInfo As PropertyInfo = personType.GetProperty(kvp.Key)

    If propInfo IsNot Nothing Then
        propInfo.SetValue(myPerson, kvp.Value)
    End If
Next

answered Nov 16, 2010 at 4:29

Adam Maras

26.9k9 gold badges69 silver badges91 bronze badges

Sign up to request clarification or add additional context in comments.

2 Comments

Brett Over a year ago

Thanks for the great example. Apparently Reflection is really expensive. Is this true? If so (and there is no other method of doing this), I might write custom web services for each form. Thanks!

Adam Maras Over a year ago

Reflection can be expensive when abused. I don't know enough about your projects to say whether or not the overhead of Reflection is acceptable, but there are steps you can take (like caching the PropertyInfo objects you look up in a Dictionary(Of String, PropertyInfo) for faster retrieval) that can reduce that overhead. I'd say, try it and see if it's fast enough. If you find the speed to be unacceptable, then go the route of optimization/caching or your custom web services.

Collectives™ on Stack Overflow

VB .NET Access a class property by string value

1 Answer 1

2 Comments

Your Answer

Linked

Hot Network Questions

Collectives™ on Stack Overflow

1 Answer 1

2 Comments

Your Answer

Sign up or log in

Post as a guest

Linked

Related