c# - 如何透视 IEnumerable

Question

我需要“转动”或“旋转”一组对象。该示例将清除我需要做的事情:

var people = new List<Person>(new[] {
                new Person{ Name="Ronnie",Age=25, HairColor="Brown",EyeColor="Blue"},
                new Person{ Name="Tina",Age=25, HairColor="Brown",EyeColor="Green"},
                new Person{ Name="Lukus",Age=4, HairColor="Blonde",EyeColor="Blue"}    
            });

DataTable rotatedData = people.Pivot("Name", "Property");                

/* Results In:
* ___________________________________________
* Property  |  Ronnie  |   Tina    |   Lukus
* ___________________________________________
* Age       |  25      |   25      |   4
* HairColor |  Brown   |   Brown   |   Blonde
* EyeColor  |  Blue    |   Green   |   Blue
* ____________________________________________
*/

这是我编写的实现此目的的代码:

/// <summary>Converts an IEnumerable into a pivoted DataTable object.</summary>
/// <param name="collection">The IEnumerable object to pivot and convert.</param>
/// <param name="headingMember">The name of a public field or property member of type T to be used as column name's in the pivoted DataTable object.</param>
/// <param name="membersHeading">The name of the column that lists the public fields and properties of type T.</param>        
static DataTable Pivot<T>(this IEnumerable<T> collection, string headingMember, string membersHeading)
{
    // get object information
    var type = typeof(T);
    var members = new List<MemberInfo>();
    members.AddRange(type.GetProperties(BindingFlags.Public | BindingFlags.Instance));
    members.AddRange(type.GetFields(BindingFlags.Public | BindingFlags.Instance));

    // create dataTable and establish schema
    var dt = new DataTable();
    dt.Columns.Add(membersHeading);
    foreach (var item in collection)
    {
        var member = members.Single(x => x.Name == headingMember);
        if (member is FieldInfo)                        
        {
            FieldInfo fieldInfo = (FieldInfo)member;
            dt.Columns.Add(fieldInfo.GetValue(item).ToString(), fieldInfo.FieldType);
        }

        if (member is PropertyInfo)
        {
            PropertyInfo propInfo = (PropertyInfo)member;
            dt.Columns.Add(propInfo.GetValue(item, null).ToString(), propInfo.PropertyType);
        }
    }

    // add rows to table
    foreach (MemberInfo member in members.Where(x => x.Name != headingMember))
    {
        var row = dt.NewRow();
        row[0] = member.Name;
        int i = 1;

        foreach (var item in collection)
        {
            if (member is FieldInfo)
                row[i++] = ((FieldInfo)member).GetValue(item);

            if (member is PropertyInfo)
                row[i++] = ((PropertyInfo)member).GetValue(item, null);
        }

        dt.Rows.Add(row);
    }

    return dt;
}

有没有 什么是更好的方法？

Answer 1

您可以简单地通过在名称上使用 Group 来对 IEnumerable 进行透视。假设名称是不同的。旋转数据后，您可以 Convert IEnumerable to DataTable .