如何导入/解析集合数据？

Question

我有一个创建 Excel 文件的项目，我想添加一些导入功能。简而言之，我想让用户能够编写以下代码：

worksheet.Cell(1, 1).Value = collectionObject;

（其中collectionObject实现了IEnumerable）

如何解析任何类型的 IEnumerable 并提取每个项目的属性和字段的值？

这是我失败的尝试：

class Program
{
    static void Main(string[] args)
    {
        // It fails with a list of strings
        var listOfStrings = new List<String>();
        listOfStrings.Add("House");
        listOfStrings.Add("Car");
        new ParseCollections().ParseCollection(listOfStrings, 1, 1);
        // Get error "Parameter count mismatch." when calling info.GetValue(m, null).ToString()
        // The property is an array "Chars". 
        // I tried filtering the property with "info as IEnumerable == null" but it doesn't catch it.
        // How can I filter collection properties here?


        // It works with a list of POCO
        var listOfPOCO = new List<Person>();
        listOfPOCO.Add(new Person() { Name = "John", Age = 30 });
        listOfPOCO.Add(new Person() { Name = "Jane", Age = 25 });
        new ParseCollections().ParseCollection(listOfPOCO, 1, 1);
    }

    class Person
    {
        public String Name { get; set; }
        public Int32 Age { get; set; }
    }
}
class ParseCollections
{
    public void ParseCollection(Object collectionObject, Int32 initialRow, Int32 initialColumn)
    {
        var asEnumerable = collectionObject as IEnumerable;
        if (asEnumerable != null)
        {
            var ro = initialRow;
            foreach (var m in asEnumerable)
            {
                var co = initialColumn;
                var fieldInfo = m.GetType().GetFields();
                foreach (var info in fieldInfo)
                {
                    Console.WriteLine("Cell({0}, {1}) = {2}", ro, co, info.GetValue(m).ToString());
                    co++;
                }
                var propertyInfo = m.GetType().GetProperties();
                foreach (var info in propertyInfo)
                {
                    Console.WriteLine("Cell({0}, {1}) = {2}", ro, co, info.GetValue(m, null).ToString());
                    co++;
                }
                ro++;
            }
        } 
    }
}

Answer 1

以下解析一个 IEnumerable 对象，但它似乎是做作的方式，只是乞求用户传递一个会破坏函数的 IEnumerable :(

        public void ParseCollection(Object collectionObject, Int32 initialRow, Int32 initialColumn)
    {
        var asEnumerable = collectionObject as IEnumerable;
        if (asEnumerable != null)
        {
            var ro = initialRow;
            foreach (var m in asEnumerable)
            {
                var co = initialColumn;

                if (m.GetType().IsPrimitive || m.GetType() == typeof(String) || m.GetType() == typeof(DateTime))
                {
                    SetValue(m, ro, co);
                }
                else if (m.GetType().IsArray )
                {
                    dynamic arr = m;
                    foreach(var item in arr)
                    {
                        SetValue(item, ro, co);
                        co++;
                    }
                }
                else if ((m as DataRow) != null)
                {
                    foreach (var item in (m as DataRow).ItemArray)
                    {
                        SetValue(item, ro, co);
                        co++;
                    }
                }
                else
                {
                    var fieldInfo = m.GetType().GetFields();
                    foreach (var info in fieldInfo)
                    {
                        SetValue(info.GetValue(m), ro, co);
                        co++;
                    }
                    var propertyInfo = m.GetType().GetProperties();
                    foreach (var info in propertyInfo)
                    {
                        if ((info as IEnumerable) == null)
                            SetValue(info.GetValue(m, null), ro, co);
                        co++;
                    }
                }
                ro++;
            }
        } 
    }
    private static void SetValue(object objWithValue, int ro, int co)
    {
        String str = String.Empty;
        if (objWithValue != null)
            str = objWithValue.ToString();

        Console.WriteLine("Cell({0}, {1}) = {2}", ro, co, str);
    }