Lambda 表达式比较字符串

Question

我有一个可行的代码StartsWith，但我需要使用Compare而不是StartsWith：

LambdaExpression startsWithLambda = (Expression<Func<string, string, bool>>)((x, s) => x.StartsWith(s)); // works
//  LambdaExpression startsWithLambda = (Expression<Func<string, string, bool>>)((x, s) => string.Compare(x,s) > 0); -  doesn't work
MethodInfo startsWithMI = (startsWithLambda.Body as MethodCallExpression).Method;
ParameterExpression param = Expression.Parameter(typeof(T));
Expression nameProp = Expression.Property(param, _propertyName);
Expression filteredOk = Expression.Constant(true);
Expression startsWithStringExpr = Expression.Constant(_filter);
Expression startsWithCondition = Expression.Call(nameProp, startsWithMI, startsWithStringExpr);
filteredOk = Expression.AndAlso(filteredOk, startsWithCondition);
Expression<Func<T, bool>> where = Expression.Lambda<Func<T, bool>>(filteredOk, new ParameterExpression[] { param });
var result = orderedQuery.Where(where).Take(_linesCount);

如何使用 lambda 表达式实现string.Compare？

Answer 1

找到了解决方案： 表达式 startsWithCondition = Expression.Call（startsWithMI， nameProp， startsWithStringExpr）;

如果在调用方法中使用静态方法参数，则应切换。