c#的世界里有遇到了问题，大家帮忙看看！

using System;
using System.Collections.Generic;
using System.Linq;
using System.Text; namespace TrapezoidalShape
{
public class Trapezoidal
{
private int Long1;
private int Long2;
private int High;
public Trapezoidal(int Long1, int Long2, int High)
{
this.Long1 = Long1;
this.Long2 = Long2;
this.High = High;
}
public override int getArea()
{
return (Long1 + Long2) * High / 2;
}
}
public class testshape
{
static void Main()
{
TrapezoidalShape = new Trapezoidal(6, 8, 10);
System.Console.WriteLine("它的面积是");
}
}
}
错误提示是这个，我不知道怎么改了，大家看看