Edit an Object Property Value Dynamically at Run Time

no need to write a huge switch statement to make a run time decision

Imagine you have an Object with 50 properties, and at runtime, you only need to change the value of one of them. You could write a switch statement to run through all of them, but there is a better way. This is how it would be done with a switch:
switch(propertyName)
{
    case "Name": obj.Name = newVal; break;
    case "Phone": obj.Phone = newVal; break;
    ///and so on...

That sounds like a terrible idea. With Reflection, it was easy to build an extension to update any object with a new value at runtime (provided it can be written to) with the following code:
public static void SetPropertyValue(this object o, 
    string propertyName, object newValue)
{
    PropertyInfo pi;
    pi = o.GetType().GetProperty(propertyName);
    if (pi == null)
        throw new Exception("No Property [" + 
            propertyName + "] in Object [" + 
            o.GetType().ToString() + "]");
    if (!pi.CanWrite)
        throw new Exception("Property [" + 
            propertyName + "] in Object [" + 
            o.GetType().ToString() + 
            "] does not allow writes");
    pi.SetValue(o, newValue, null);
}

Now, instead of that 50+ line mess above, all you need to do to change the "Phone" property to 'newVal' is:
obj.SetPropertyValue("Phone", newVal);

I added this to my Naspinski.Utilities Set on CodePlex as well.

Comments (2) -

  • Instead of 'public static void ChangePropertyValue' you meant 'public static void SetPropertyValue' ?

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