Cannot cast from source type to destination type

Question

I am new to C# so I was doing some tutorials. I get this error when I try to run a tutorial Android project from Xamarin Studio:

A System.InvalidCastException was thrown. Cannot cast from source type to destination type.

This is the code that gives the error:

public Java.Lang.Object [] GetSections ()
{ 
    var intPtr = JNIEnv.NewArray (sections.ToArray ());
    var array = new JavaArray<Java.Lang.Object> (intPtr, JniHandleOwnership.TransferLocalRef);
    return (Java.Lang.Object []) array;
}

How can I fix this?

Answer 1

You're casting JavaArray<Java.Lang.Object> to Java.Lang.Object [] .

Change the return type of GetSessions() to JavaArray<Java.Lang.Object>

public JavaArray<Java.Lang.Object> GetSections ()
{ 
    var intPtr = JNIEnv.NewArray (sections.ToArray ());
    return new JavaArray<Java.Lang.Object> (intPtr, JniHandleOwnership.TransferLocalRef);
}

Answer 2

Your second problem probably means that you have implemented a interfacit wich GetSections method needs a return type of Java.Lang.Object.

If you made your interface yourself you probably made the same mistake there as what you did in this method.

So:

public JavaArray<Java.Lang.Object> GetSections ()
{ 
    var intPtr = JNIEnv.NewArray (sections.ToArray ());
    return new JavaArray<Java.Lang.Object> (intPtr, JniHandleOwnership.TransferLocalRef);
} 

and your interface should look like this:

public JavaArray<Java.Lang.Object> GetSections ();

i think you made the same mistake twice