如何动态生成ToUpper()表达式

[yxx7348]

新手请教：
如何动态生成以下表达式：u => u.公司.ToUpper().Contains("四川")
现在不会的是ToUpper()部分, 除此之外用以下代码已实现：

ParameterExpression parameter = Expression.Parameter(typeof(业务记录), "t");
MemberExpression member = Expression.PropertyOrField(parameter, field);
ConstantExpression constant = Expression.Constant(keyword);
System.Reflection.MethodInfo method = typeof(string).GetMethod("Contains", new[] { typeof(string) });
var containsMethodExp = Expression.Call(ToUpperMethodExp, method, constant);
var lambda = Expression.Lambda<Func<业务记录, Boolean>>(containsMethodExp, parameter);

[stherix]

            ParameterExpression parameter = Expression.Parameter(typeof(业务记录), "t");
            MemberExpression member = Expression.PropertyOrField(parameter, field);
            ConstantExpression constant = Expression.Constant(keyword);
            System.Reflection.MethodInfo methodToUpper = typeof(string).GetMethod("ToUpper", new Type[] { });
            var ToUpperMethodExp = Expression.Call(member, methodToUpper);
            System.Reflection.MethodInfo method = typeof(string).GetMethod("Contains", new[] { typeof(string) });            
            var containsMethodExp = Expression.Call(ToUpperMethodExp, method, constant);
            var lambda = Expression.Lambda<Func<业务记录, Boolean>>(containsMethodExp, parameter);

[yxx7348]

感谢stherix的热心解答，非常感谢！！！