Question

Consider this:

var propertyinfo = typeof(Customer).GetProperty(sortExpressionStr);
Type orderType = propertyinfo.PropertyType;

now I want to declare

Func<int,orderType>

I know its not possible directly since ordertype is at runtime but is there is any workaround ?

this is exactly what I want to do :

var propertyinfo = typeof(T).GetProperty(sortExpressionStr);
Type orderType = propertyinfo.PropertyType;

var param = Expression.Parameter(typeof(T), "x");
var sortExpression = (Expression.Lambda<Func<T, orderType>>
   (Expression.Convert(Expression.Property(param, sortExpressionStr), typeof(orderType)), param));

all this because I want to convert:

Expression<Func<T,object>> to Expression<Func<T,orderType>>

or if its not possible then I want to create it from the first place with the right type , the case is as following:

I’m inside a method which have a type(Customer) and a property name of that type I want to order by it , I want to create a sort expression tree to pass it to Orderby (here).

Answer 1

linqClass.OrderBy(GetSortExpression(sortstr));


public static Expression<Func<T,object>> GetSortExpression<T>(string sortExpressionStr)
    {
        var param = Expression.Parameter(typeof(T), "x");
        var sortExpression = Expression.Lambda<Func<T, object>>(Expression.Property(param, sortExpressionStr), param);
        return sortExpression;
    }

this worked my problem was i used to pass extra parameter Typeof(Object) and orderby used to tell me it cant sort by Object type. thanks all

thanks dtb i will check if your answer work too and i will accept it if it works if not i will accept thsi one.