C# - GetValue - Object Does Not Match Target Type

Question

I am trying to write a generic method to compare two objects (I purposefully have two different types coming in. The second one has the same properties as the first one. The first just has more.).

I want to make sure the properties have the same values. The following code works for most of the properties that I have in the objects, but occasionally it throws the:

"Object Does Not Match Target Type"

...error at

var valFirst = prop.GetValue(manuallyCreated, null) as IComparable;

public static bool SameCompare<T, T2>(T manuallyCreated, T2 generated){
var propertiesForGenerated = generated.GetType().GetProperties();
int compareValue = 0;

foreach (var prop in propertiesForGenerated) {

    var valFirst = prop.GetValue(manuallyCreated, null) as IComparable;
    var valSecond = prop.GetValue(generated, null) as IComparable;
    if (valFirst == null && valSecond == null)
        continue;
    else if (valFirst == null) {
        System.Diagnostics.Debug.WriteLine(prop + "s are not equal");
        return false;
    }
    else if (valSecond == null) {
        System.Diagnostics.Debug.WriteLine(prop + "s are not equal");
        return false;
    }
    else if (prop.PropertyType == typeof(System.DateTime)) {
        TimeSpan timeDiff = (DateTime)valFirst - (DateTime)valSecond;
        if (timeDiff.Seconds != 0) {
            System.Diagnostics.Debug.WriteLine(prop + "s are not equal");
            return false;
        }
    }
    else
        compareValue = valFirst.CompareTo(valSecond);
    if (compareValue != 0) {
        System.Diagnostics.Debug.WriteLine(prop + "s are not equal");
        return false;
    }
}

System.Diagnostics.Debug.WriteLine("All values are equal");
return true;
}

Answer 1

Each property defined on a type in .NET is different, even if they have the same name. You'd have to do this:

foreach (var prop in propertiesForGenerated) 
{
    var otherProp = typeof(T).GetProperty(prop.Name);
    var valFirst = otherProp.GetValue(manuallyCreated, null) as IComparable;
    var valSecond = prop.GetValue(generated, null) as IComparable;

    ...

Of course this doesn't take into account that some properties defined on T may not exist on T2, and vice versa.