将List转化成 DataTable--调整可空类型的转化错误

加载表结构并保持成XML

string cmdText = @"select   * from kb_lable_temp where 1=2";
using (SqlConnection conn = new SqlConnection(DBCtx.ConnStr))
{
DataTable dt = new DataTable();
SqlCommand cmd = new SqlCommand(cmdText,conn);
conn.Open();
using (var dr = cmd.ExecuteReader(CommandBehavior.SchemaOnly))
{
dt.Load(dr);
dt.WriteXmlSchema("C:\\xxx.xml");
} }
DataTable dt3 = new DataTable();
dt3.ReadXmlSchema("C:\\xxx.xml");

List<T>到DataTable

using System.Data;
using System.Collections.Generic;
using System.Reflection;
using System;
using System.Collections;
namespace F.Studio.Util
{
public static class DataTableExtensions
{
/// <summary>
/// 转化一个DataTable
/// </summary>
/// <typeparam name="T"></typeparam>
/// <param name="list"></param>
/// <returns></returns>
public static DataTable ToDataTable<T>(this IEnumerable<T> list,params string[] tableName)
{
//创建属性的集合
List<PropertyInfo> pList = new List<PropertyInfo>();
//获得反射的入口
Type type = typeof(T);
string tname = "Table1";
if (tableName.Length >= )
{
tname = tableName[];
}
DataTable dt = new DataTable(tname);
//把所有的public属性加入到集合 并添加DataTable的列
Array.ForEach<PropertyInfo>(type.GetProperties(), p =>
{
pList.Add(p);
var theType=p.PropertyType;
//处理可空类型
if (theType.IsGenericType && theType.GetGenericTypeDefinition().Equals(typeof(Nullable<>)))
{
dt.Columns.Add(p.Name,Nullable.GetUnderlyingType(theType));
}
else
{
dt.Columns.Add(p.Name, theType);
}
});
foreach (var item in list)
{
//创建一个DataRow实例
DataRow row = dt.NewRow();
//给row 赋值
pList.ForEach(p =>
{
var v=p.GetValue(item, null);
row[p.Name] = v==null ? DBNull.Value : v; });
//加入到DataTable
dt.Rows.Add(row);
}
return dt;
}
}
}
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