集合List与DataTable互转

/// <summary>
/// 将泛类型集合List类转换成DataTable
/// </summary>
/// <param name="list">泛类型集合</param>
/// <returns></returns>
public static DataTable ListToDataTable<T>(List<T> entitys)
{
//检查实体集合不能为空
if (entitys == null || entitys.Count < 1)
{
throw new Exception("需转换的集合为空");
}
//取出第一个实体的所有Propertie
Type entityType = entitys[0].GetType();
PropertyInfo[] entityProperties = entityType.GetProperties();

//生成DataTable的structure
//生产代码中，应将生成的DataTable结构Cache起来，此处略
DataTable dt = new DataTable();
for (int i = 0; i < entityProperties.Length; i++)
{
//dt.Columns.Add(entityProperties[i].Name, entityProperties[i].PropertyType);
dt.Columns.Add(entityProperties[i].Name);
}
//将所有entity添加到DataTable中
foreach (object entity in entitys)
{
//检查所有的的实体都为同一类型
if (entity.GetType() != entityType)
{
throw new Exception("要转换的集合元素类型不一致");
}
object[] entityValues = new object[entityProperties.Length];
for (int i = 0; i < entityProperties.Length; i++)
{
entityValues[i] = entityProperties[i].GetValue(entity, null);
}
dt.Rows.Add(entityValues);
}
return dt;
}

 

将DataTable 转为 List

IEnumerable<MySysData> newdata = from item in data.Tables[0].AsEnumerable()
                                         where item["UserState"].ToString() == "启用"
                                         orderby item["UserRealName"].ToString()
                                         select new MySysData { UserName = item["UserName"].ToString(), UserQQ = item["UserQQ"].ToString() };