Question

我有一个excel导出器类，必须从第三方获取过滤信息并使用该信息过滤数据。过滤信息以“equals”，“greatherthan”等字符串形式出现。生成可重用代码的最佳方法是什么，可以将这些过滤类型转换为c＃代码。

我认为将它们转换为运算符并返回它可能会很好。但我不知道这是否可能，甚至不是一个好主意。你觉得怎么样？

Answer 1

试试这个：

  public class ExcelFiltersManager
{
    public static class ExcelFilters
    {
        public const string Equal = "equals";
        public const string GreaterThen = "greaterthan";

        // complete here the other operators.
    }

    static class Operators
    {
        // C# compiler converts overloaded operators to functions with name op_XXXX where XXXX is the opration

        public const string Equality = "op_Equality";
        public const string InEquality = "op_Inequality";
        public const string LessThan = "op_LessThan";
        public const string GreaterThan = "op_GreaterThan";
        public const string LessThanOrEqual = "op_LessThanOrEqual";
        public const string GreaterThanOrEqual = "op_GreaterThanOrEqual";
    }

    public bool GetOperatorBooleanResult<T>(string excelFilter, T value1, T value2)
    {
        MethodInfo mi = typeof(T).GetMethod(GetOperatorCompileName(excelFilter), BindingFlags.Static | BindingFlags.Public);
        return (bool)mi.Invoke(null, new object[] { value1, value2 });
    }

    private string GetOperatorCompileName(string excelFilter)
    {
        string operatorCompileName = string.Empty;

        switch (excelFilter)
        {
            case ExcelFilters.Equal:
                operatorCompileName = Operators.Equality;
                break;
            case ExcelFilters.GreaterThen:
                operatorCompileName = Operators.GreaterThan;
                break;

                // continue here the mapping with the rest of operators
        }

        return operatorCompileName;
    }
}

然后在您的代码中，您可以使用以下内容来获取过滤器的结果：

decimal value1 = 5;
decimal value2 = 10;

bool result = GetOperatorBooleanResult(ExcelFilters.GreaterThen, value1, value2);

在c＃中，可以传递或返回类型之类的运算符

1 个答案: