C# simple reflection

Question

I have a class that contains another poco class with simple get set properties:

public class PersonalInformation { public string FirstName { get; set; } public string FirstSomethingElse { get; set; } }

I would like to find out if the current instance's PersonalInformation.FirstName has a value. I can't figure out how to obtain it via reflection:

foreach (PropertyInfo property in this.PersonalInformation.GetType().GetProperties()) { if (property.Name.Contains("First")) { if (property.GetValue(XXX, null) != null) do something... } }

The instance I have is "this", which does not work, neither does this.PersonalInformation. What am I doing wrong?

Thank you for your response,

Aldo

Addendum: I'm using ASP.NET MVC3. In my razor view I can do the following very easily:

foreach (var property in Model.PersonalInformation.GetType().GetProperties()) { <div class="editor-line"> @if (property.Name != null) { <label>@(property.Name)</label> @Html.Editor(property.Name) } </div> }

there is a property.Value member that returns the current value of the field. This field comes from a poco class, as you see above. What would be the equivalent code in the code-behind?

What have you tried? Do you get an exception? Should you be using reflection? — lesderid
– lesderid, Commented Dec 12, 2012 at 20:48
>> What do you mean by "doesn't work?" - means I'm getting an object exception — aldosa
– aldosa, Commented Dec 12, 2012 at 20:59
>> Why are you using reflection? : this is an ultrasimplified example. Let's pretend I have hundreds of properties in my form. — aldosa
– aldosa, Commented Dec 12, 2012 at 21:00

Jon Skeet · Accepted Answer · 2012-12-12 20:43:47Z

this.PersonalInformation certainly should work. After all, that's the target you're talking about.

Sample code:

using System; using System.Reflection; public class PersonalInformation { public string FirstName { get; set; } public string FirstSomethingElse { get; set; } } public class Foo { public PersonalInformation PersonalInformation { get; set; } public void ShowProperties() { foreach (var property in this.PersonalInformation .GetType() .GetProperties()) { var value = property.GetValue(this.PersonalInformation, null); Console.WriteLine("{0}: {1}", property.Name, value); } } } class Test { static void Main() { Foo foo = new Foo { PersonalInformation = new PersonalInformation { FirstName = "Fred", FirstSomethingElse = "XYZ" } }; foo.ShowProperties(); } }

Although if you just "want to find out if the current instance's PersonalInformation.FirstName has a value" then I don't see why you're using reflection...

Kevin · Accepted Answer · 2012-12-12 20:46:22Z

-3

GetProperties returns a PropertyInfo[], not a single PropertyInfo.

answered Dec 12, 2012 at 20:46

Kevin

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Jon Skeet Over a year ago

... which is why he's iterating over them.

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