求如何将LINQ语句查询出的数据类型转换为DATATABLE类型
本帖最后由 baonan0811 于 2011-05-31 12:55:59 编辑
private DataTable MergeDataTable(DataTable dt1, DataTable dt2)
{
DataTable returnDt = new DataTable();
var merge = from main in dt1.AsEnumerable()
join station in dt2.AsEnumerable() on main.Field<string>("区站号") equals station.Field<string>("区站号")
select new
{
区站号 = main.Field<string>("区站号"),
日期时间 = main.Field<string>("日期时间"),
站名 = station.Field<string>("站名"),
市 = station.Field<string>("市"),
县 = station.Field<string>("县"),
经度 = station.Field<object>("经度"),
纬度 = station.Field<object>("纬度"),
三小时雨量 = main.Field<object>("三小时累积雨量"),
};
returnDt = merge.ConvertToDataTable();
return returnDt;
}
//使用：
merge.ToList().ConvertToDataTable();
using System;
using System.Reflection;
using System.Data;
/// <summary>
/// Convert Generic List Type to DataTable.
/// </summary>
public class List2DataTable
{
#region "Convert Generic List to DataTable"
/// <summary>
/// Convert a List{T} to a DataTable.
/// </summary>
/// <typeparam name="T"></typeparam>
/// <param name="items"></param>
/// <returns></returns>
public static DataTable ConvertToDataTable<T>(this List<T> items)
{
var tb = new DataTable(typeof(T).Name);
PropertyInfo[] props = typeof(T).GetProperties(BindingFlags.Public
[解决办法]
BindingFlags.Instance);
foreach (PropertyInfo prop in props)
{
Type t = GetCoreType(prop.PropertyType);
tb.Columns.Add(prop.Name, t);
}
foreach (T item in items)
{
var values = new object[props.Length];
for (int i = 0; i < props.Length; i++)
{
values[i] = props[i].GetValue(item, null);
}
tb.Rows.Add(values);
}
return tb;
}
/// <summary>
/// Determine of specified type is nullable
/// </summary>
/// <param name="t"></param>
/// <returns></returns>
public static bool IsNullable(Type t)
{
return !t.IsValueType
[解决办法]
(t.IsGenericType && t.GetGenericTypeDefinition() == typeof(Nullable<>));
}
/// <summary>
/// Return underlying type if type is Nullable otherwise return the type.
/// </summary>
/// <param name="t"></param>
/// <returns></returns>
public static Type GetCoreType(Type t)
{
if (t != null && IsNullable(t))
{
if (!t.IsValueType)
{
return t;
}
else
{
return Nullable.GetUnderlyingType(t);
}
}
else
{
return t;
}
}
#endregion
}
