Refer to a property name by variable

Question

Is there a way to refer to a property name with a variable?

Scenario: Object A have public integer property X an Z, so...

public void setProperty(int index, int value)
{
    string property = "";

    if (index == 1)
    {
        // set the property X with 'value'
        property = "X";
    }
    else 
    {
        // set the property Z with 'value'
        property = "Z";
    }

    A.{property} = value;
}

This is a silly example so please believe, I have an use for this.

Answer 1

Easy:

a.GetType().GetProperty("X").SetValue(a, value);

Note that GetProperty("X") returns null if type of a has no property named "X".

To set property in the syntax you have provided just write an extension method:

public static class Extensions
{
    public static void SetProperty(this object obj, string propertyName, object value)
    {
        var propertyInfo = obj.GetType().GetProperty(propertyName);
        if (propertyInfo == null) return;
        propertyInfo.SetValue(obj, value);
    }
}

And use it like this:

a.SetProperty(propertyName, value);

UPD

Note that this reflection-based method is relatively slow. For better performance use dynamic code generation or expression trees. There are good libraries that can do this complex stuff for you. For example, FastMember.