using System;
using System.Collections;
using System.Collections.Generic;
using System.Linq;
using System.Linq.Expressions;
using System.Text;
using System.Data;
using System.Data.SqlTypes;
using System.Data.Common;

using Xunit;

namespace LinqStudy.Test.LinqToObject
{
    /// <summary>
    /// 转换运算符
    /// </summary>
    public class TypeConvertTest 
    {
        /// <summary>
        ///  AsEnumeralbe：
        /// System.Linq.Enumeralbe中，扩展方法
        /// AsEnumeralbe() 是延迟执行
        /// </summary>
        [Fact]
        public void AsEnumeralbe_Test()
        {
            DataTable dt=new DataTable();
            DataColumn col_id=new DataColumn("Id");
            col_id.AllowDBNull=false;
            col_id.AutoIncrementSeed=1;
            col_id.AutoIncrement=true;
            col_id.AutoIncrementStep=1;
            col_id.DataType=typeof(int);

            DataColumn col_name=new DataColumn("Name");
            col_name.AllowDBNull=true;
            col_name.AutoIncrement=false;
            col_name.DataType=typeof(string);
            col_name.DefaultValue=string.Empty;

            DataColumn col_age=new DataColumn("Age");
            col_age.AllowDBNull=false;
            col_age.AutoIncrement=false;
            col_age.DataType=typeof(int);
            col_age.DefaultValue=20;

            dt.Columns.Add(col_id);
            dt.Columns.Add(col_name);
            dt.Columns.Add(col_age);

            var row_one = dt.NewRow();
            row_one[1]="王高峰";
            row_one[2]=21;

            dt.Rows.Add(row_one);

            var cc = from row in dt.Select()
                     select row;
            var dd = cc.ToList();

        }

        /// <summary>
        /// 1.IEnumeralbe 转换为 IQueryable
        /// 2.IEnumeralbe<T> 转换为 IQueryable<T>
        /// </summary>
        [Fact]
        public void AsQueryable_Test()
        {
           IEnumerable bb= Enumerable.Range(1,100);

           var cc=bb.AsQueryable();

           int[] t=new int[]{1,2,3};

           t.AsEnumerable();
        }
    }
}