Needs help to understand delegate and GetGetMethod to Get property value-CodePudding

I am trying to undersand how to use delegate and GetGetMethod/GetSetMethod to get and set property. Say I have a class PerformanceCumulativePeriodEnd and I am only interested in getting and setting the decimal properties.

Setter is easy to do, but how do I create a getter delegation?

PerformanceCumulativePeriodEnd myObject = new PerformanceCumulativePeriodEnd();
myObject.Cumulative10Y = 2344;

foreach (var propertyInfo in typeof(PerformanceCumulativePeriodEnd).GetProperties())
{
  if (propertyInfo.PropertyType.IsAssignableFrom(typeof(decimal)))
    {
       var setter = (Action<PerformanceCumulativePeriodEnd, decimal? 
                 >)Delegate.CreateDelegate(
                    typeof(Action<PerformanceCumulativePeriodEnd, decimal?>), 
                  propertyInfo.GetSetMethod());
       setter.Invoke(myObject, 111);

       var getter =??? //How do I create a Action for Getter?
    }
 }

CodePudding user response：

The immediate equivalent would be:

var myObject = new PerformanceCumulativePeriodEnd();
myObject.Cumulative10Y = 2344;

foreach (var propertyInfo in typeof(PerformanceCumulativePeriodEnd).GetProperties())
{
    if (propertyInfo.PropertyType == typeof(decimal?))
    {
        var setter = (Action<PerformanceCumulativePeriodEnd, decimal? 
            >)Delegate.CreateDelegate(
            typeof(Action<PerformanceCumulativePeriodEnd, decimal?>), 
            propertyInfo.GetSetMethod());
        setter(myObject, 111);
        
        var getter = (Func<PerformanceCumulativePeriodEnd, decimal? 
            >)Delegate.CreateDelegate(
            typeof(Func<PerformanceCumulativePeriodEnd, decimal?>), 
            propertyInfo.GetGetMethod());
        var val = getter(myObject);
        
    }
}

I changed the criterion to == typeof(decimal?) to include only properties whose exact type is nullable decimal.

Bonus: Here is another version:

var myObject = new PerformanceCumulativePeriodEnd();
myObject.Cumulative10Y = 2344;

foreach (var propertyInfo in typeof(PerformanceCumulativePeriodEnd).GetProperties())
{
    if (propertyInfo.PropertyType == typeof(decimal?))
    {
        Action<PerformanceCumulativePeriodEnd, decimal?> setter =
            (obj, v) => propertyInfo.GetSetMethod().Invoke(obj, new object[] { v });
        setter(myObject, 111);
        
        Func<PerformanceCumulativePeriodEnd, decimal?> getter = 
            obj => (decimal?)propertyInfo.GetGetMethod().Invoke(obj, null);
        var val = getter(myObject);
        
    }
}

In case you do not really need them as delegates:

var myObject = new PerformanceCumulativePeriodEnd();
myObject.Cumulative10Y = 2344;

foreach (var propertyInfo in typeof(PerformanceCumulativePeriodEnd).GetProperties())
{
    if (propertyInfo.PropertyType == typeof(decimal?))
    {
        // set
        propertyInfo.GetSetMethod().Invoke(myObject, new object[] { 111m });

        // get
        var val = (decimal?)propertyInfo.GetGetMethod().Invoke(myObject, null);
        
    }
}

CodePudding user response：

You could try to define your delegate which returns a decimal and use the GetMethod property to create your delegate.

Something like:

public delegate Result ActionResult<in T, Result>(T obj);

and then in your main function:

var getter = (ActionResult<PerformanceCumulativePeriodEnd, decimal?>)Delegate.CreateDelegate(
               typeof(ActionResult<PerformanceCumulativePeriodEnd, decimal?>), propertyInfo.GetMethod);
                
var i = getter.Invoke(myObject);