我有几个方法返回不同的泛型列表。

在。net中存在任何类静态方法或将任何列表转换为数据表?我唯一能想到的是使用反射来做到这一点。

如果我有这个:

List<Whatever> whatever = new List<Whatever>();

(这下代码当然不工作,但我想有这样的可能性:

DataTable dt = (DataTable) whatever;

当前回答

我认为它更方便和容易使用。

   List<Whatever> _lobj= new List<Whatever>(); 
    var json = JsonConvert.SerializeObject(_lobj);
                DataTable dt = (DataTable)JsonConvert.DeserializeObject(json, (typeof(DataTable)));

其他回答

我还必须想出一个替代解决方案,因为这里列出的选项都不适合我。我使用了一个IEnumerable,返回一个IEnumerable,属性不能被枚举。这招奏效了:

// remove "this" if not on C# 3.0 / .NET 3.5
public static DataTable ConvertToDataTable<T>(this IEnumerable<T> data)
{
    List<IDataRecord> list = data.Cast<IDataRecord>().ToList();

    PropertyDescriptorCollection props = null;
    DataTable table = new DataTable();
    if (list != null && list.Count > 0)
    {
        props = TypeDescriptor.GetProperties(list[0]);
        for (int i = 0; i < props.Count; i++)
        {
            PropertyDescriptor prop = props[i];
            table.Columns.Add(prop.Name, Nullable.GetUnderlyingType(prop.PropertyType) ?? prop.PropertyType);
        }
    }
    if (props != null)
    {
        object[] values = new object[props.Count];
        foreach (T item in data)
        {
            for (int i = 0; i < values.Length; i++)
            {
                values[i] = props[i].GetValue(item) ?? DBNull.Value;
            }
            table.Rows.Add(values);
        }
    }
    return table;
}

Marc Gravell的回答,但是用VB。网

Public Shared Function ToDataTable(Of T)(data As IList(Of T)) As DataTable
    Dim props As PropertyDescriptorCollection = TypeDescriptor.GetProperties(GetType(T))
    Dim table As New DataTable()
    For i As Integer = 0 To props.Count - 1
            Dim prop As PropertyDescriptor = props(i)
            table.Columns.Add(prop.Name, prop.PropertyType)
    Next
    Dim values As Object() = New Object(props.Count - 1) {}
    For Each item As T In data
            For i As Integer = 0 To values.Length - 1
                    values(i) = props(i).GetValue(item)
            Next
            table.Rows.Add(values)
    Next
    Return table
End Function
List<object> Basket;

string json = JsonConvert.SerializeObject(Basket, Formatting.Indented);
DataTable dtUsingMethod = Business.GetJSONToDataTableUsingNewtonSoftDll(json);



public static DataTable GetJSONToDataTableUsingNewtonSoftDll(string JSONData)
{
    DataTable dt = (DataTable)JsonConvert.DeserializeObject(JSONData, (typeof(DataTable)));
    return dt;
}

将通用列表转换为数据表

使用Newtonsoft.Json;

public DataTable GenericToDataTable(IList<T> list)
{
    var json = JsonConvert.SerializeObject(list);
    DataTable dt = (DataTable)JsonConvert.DeserializeObject(json, (typeof(DataTable)));
    return dt;
}
  using System;
using System.Collections.Generic;
using System.Linq;
using System.Web;
using System.Web.UI;
using System.Web.UI.WebControls;
using System.Data;
using System.ComponentModel;

public partial class Default3 : System.Web.UI.Page
{
    protected void Page_Load(object sender, EventArgs e)
    {
        DataTable dt = new DataTable();
        dt = lstEmployee.ConvertToDataTable();
    }
    public static DataTable ConvertToDataTable<T>(IList<T> list) where T : class
    {
        try
        {
            DataTable table = CreateDataTable<T>();
            Type objType = typeof(T);
            PropertyDescriptorCollection properties = TypeDescriptor.GetProperties(objType);
            foreach (T item in list)
            {
                DataRow row = table.NewRow();
                foreach (PropertyDescriptor property in properties)
                {
                    if (!CanUseType(property.PropertyType)) continue;
                    row[property.Name] = property.GetValue(item) ?? DBNull.Value;
                }

                table.Rows.Add(row);
            }
            return table;
        }
        catch (DataException ex)
        {
            return null;
        }
        catch (Exception ex)
        {
            return null;
        }

    }
    private static DataTable CreateDataTable<T>() where T : class
    {
        Type objType = typeof(T);
        DataTable table = new DataTable(objType.Name);
        PropertyDescriptorCollection properties = TypeDescriptor.GetProperties(objType);
        foreach (PropertyDescriptor property in properties)
        {
            Type propertyType = property.PropertyType;
            if (!CanUseType(propertyType)) continue;

            //nullables must use underlying types
            if (propertyType.IsGenericType && propertyType.GetGenericTypeDefinition() == typeof(Nullable<>))
                propertyType = Nullable.GetUnderlyingType(propertyType);
            //enums also need special treatment
            if (propertyType.IsEnum)
                propertyType = Enum.GetUnderlyingType(propertyType);
            table.Columns.Add(property.Name, propertyType);
        }
        return table;
    }


    private static bool CanUseType(Type propertyType)
    {
        //only strings and value types
        if (propertyType.IsArray) return false;
        if (!propertyType.IsValueType && propertyType != typeof(string)) return false;
        return true;
    }
}