/// <summary>
/// Dynamic construc delegate using expressions
/// </summary>
/// <param name="delegateType"></param>
/// <param name="func"></param>
/// <param name="control_name"></param>
/// <param name="event_name"></param>
/// <param name="program"></param>
/// <returns></returns>
public static Delegate BuildDynamicHandle(Type delegateType, Func <object[], object> func, String view_guid, String view_name, String control_name, String event_name, String program)
{
var invokeMethod = delegateType.GetMethod("Invoke");
ParameterExpression[] parms = invokeMethod.GetParameters().Select(parm => Expression.Parameter(parm.ParameterType, parm.Name)).ToArray();
CctrlEventDesc eDesc = new CctrlEventDesc(view_guid, view_name, control_name, event_name, program);
UnaryExpression[] typeAsExpression = new UnaryExpression[] { Expression.TypeAs(System.Linq.Expressions.Expression.Constant(eDesc, typeof(CctrlEventDesc)), typeof(CctrlEventDesc)) };
var instance = func.Target == null ? null : Expression.Constant(func.Target);
//var converted = parms.Select(parm => Expression.Convert(parm, typeof(object))).Concat(typeAsExpression);
var converted = typeAsExpression.Concat(parms.Select(parm => Expression.Convert(parm, typeof(object))));
NewArrayExpression paramArray = Expression.NewArrayInit(typeof(object), converted);
var call = Expression.Call(instance, func.Method, paramArray);
var body =
invokeMethod.ReturnType == typeof(void) ? (Expression)call : Expression.Convert(call, invokeMethod.ReturnType);
var expr = Expression.Lambda(delegateType, body, new ParameterExpression[] { parms[0], parms[1] }); // parms
return(expr.Compile());
}