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Get properties and values from unknown object


Question

From the world of PHP I have decided to give C# a go. I've had a search but can't seem to find the answer of how to do the equivalent to this.

$object = new Object();

$vars = get_class_vars(get_class($object));

foreach($vars as $var)
{
    doSomething($object->$var);
}

I basically have a List of an object. The object could be one of three different types and will have a set of public properties. I want to be able to get a list of the properties for the object, loop over them and then write them out to a file. I'm thinking this has something to do with c# reflection but it's all new to me.

Any help would be greatly appreciated.

2010/11/10
1
153
11/10/2010 1:11:02 PM

Accepted Answer

This should do it:

Type myType = myObject.GetType();
IList<PropertyInfo> props = new List<PropertyInfo>(myType.GetProperties());

foreach (PropertyInfo prop in props)
{
    object propValue = prop.GetValue(myObject, null);

    // Do something with propValue
}
2010/11/10
288
11/10/2010 1:15:04 PM

void Test(){
    var obj = new{a="aaa", b="bbb"};

    var val_a = obj.GetValObjDy("a"); //="aaa"
    var val_b = obj.GetValObjDy("b"); //="bbb"
}
//create in a static class
static public object GetValObjDy(this object obj, string propertyName)
{            
     return obj.GetType().GetProperty(propertyName).GetValue(obj, null);
}
2016/05/11

Yes, Reflection would be the way to go. First, you would get the Type that represents the type (at runtime) of the instance in the list. You can do this by calling the GetType method on Object. Because it is on the Object class, it's callable by every object in .NET, as all types derive from Object (well, technically, not everything, but that's not important here).

Once you have the Type instance, you can call the GetProperties method to get the PropertyInfo instances which represent the run-time informationa about the properties on the Type.

Note, you can use the overloads of GetProperties to help classify which properties you retrieve.

From there, you would just write the information out to a file.

Your code above, translated, would be:

// The instance, it can be of any type.
object o = <some object>;

// Get the type.
Type type = o.GetType();

// Get all public instance properties.
// Use the override if you want to classify
// which properties to return.
foreach (PropertyInfo info in type.GetProperties())
{
    // Do something with the property info.
    DoSomething(info);
}

Note that if you want method information or field information, you would have to call the one of the overloads of the GetMethods or GetFields methods respectively.

Also note, it's one thing to list out the members to a file, but you shouldn't use this information to drive logic based on property sets.

Assuming you have control over the implementations of the types, you should derive from a common base class or implement a common interface and make the calls on those (you can use the as or is operator to help determine which base class/interface you are working with at runtime).

However, if you don't control these type definitions and have to drive logic based on pattern matching, then that's fine.

2012/03/25

well, in C# it's similar. Here's one of the simplest examples (only for public properties):

var someObject = new { .../*properties*/... };
var propertyInfos = someObject.GetType().GetProperties();
foreach (PropertyInfo pInfo in PropertyInfos)
{
    string propertyName = pInfo.Name; //gets the name of the property
    doSomething(pInfo.GetValue(someObject,null));
}
2018/10/29

To get specific property value from property name

public class Bike{
public string Name {get;set;}
}

Bike b = new Bike {Name = "MyBike"};

to access property value of Name from string name of property

public object GetPropertyValue(string propertyName)
{
//returns value of property Name
return this.GetType().GetProperty(propertyName).GetValue(this, null);
} 
2013/08/14

You can use GetType - GetProperties - Linq Foreach:

obj.GetType().GetProperties().ToList().ForEach(p =>{
                                                        //p is each PropertyInfo
                                                        DoSomething(p);
                                                    });
2014/01/10

Source: https://stackoverflow.com/questions/4144778
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