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using System;
using System.Collections;
using System.Collections.Generic;
using System.Data;
using System.IO;
using NewLife.Reflection;
using NewLife.Serialization;
namespace NewLife.Data
{
/// <summary>数据表</summary>
public class DbTable : IEnumerable<DbRow>, ICloneable
{
#region 属性
/// <summary>数据列</summary>
public String[] Columns { get; set; }
/// <summary>数据列类型</summary>
public Type[] Types { get; set; }
/// <summary>数据行</summary>
public IList<Object[]> Rows { get; set; }
/// <summary>总函数</summary>
public Int32 Total { get; set; }
#endregion
#region 构造
#endregion
#region 从数据库读取
/// <summary>读取数据</summary>
/// <param name="dr"></param>
public void Read(IDataReader dr)
{
var count = dr.FieldCount;
// 字段
var cs = new String[count];
var ts = new Type[count];
for (var i = 0; i < count; i++)
{
if (cs[i] == null) cs[i] = dr.GetName(i);
if (ts[i] == null) ts[i] = dr.GetFieldType(i);
}
Columns = cs;
Types = ts;
// 数据
var rs = new List<Object[]>();
while (dr.Read())
{
var row = new Object[count];
for (var i = 0; i < count; i++)
{
var val = dr[i];
if (val == DBNull.Value) val = GetDefault(ts[i].GetTypeCode());
row[i] = val;
}
rs.Add(row);
}
Rows = rs;
Total = rs.Count;
}
#endregion
#region 二进制读取
private const Byte _Ver = 1;
/// <summary>从数据流读取</summary>
/// <param name="stream"></param>
public Int64 Read(Stream stream)
{
var p = stream.Position;
var bn = new Binary
{
EncodeInt = true,
Stream = stream,
};
// 读取头部
ReadHeader(bn);
// 读取全部数据
ReadData(bn, Total);
return stream.Position - p;
}
/// <summary>读取头部</summary>
/// <param name="bn"></param>
public void ReadHeader(Binary bn)
{
// 头部,幻数、版本和压缩标记
var magic = bn.ReadBytes(14).ToStr();
if (magic.Trim() != "NewLifeDbTable") throw new InvalidDataException();
var ver = bn.Read<Byte>();
var flag = bn.Read<Byte>();
// 写入头部
var count = bn.Read<Int32>();
var cs = new String[count];
var ts = new Type[count];
for (var i = 0; i < count; i++)
{
cs[i] = bn.Read<String>();
var tc = (TypeCode)bn.Read<Byte>();
ts[i] = tc.ToString().GetTypeEx(false);
}
Columns = cs;
Types = ts;
Total = bn.ReadBytes(4).ToInt();
}
/// <summary>读取数据</summary>
/// <param name="bn"></param>
/// <param name="rows"></param>
/// <returns></returns>
public Int32 ReadData(Binary bn, Int32 rows)
{
if (rows <= 0) return 0;
var ts = Types;
var count = ts.Length;
var total = 0;
var length = bn.Stream.Length;
var rs = new List<Object[]>(rows);
for (var k = 0; k < rows; k++)
{
if (bn.Stream.Position >= length) break;
var row = new Object[count];
for (var i = 0; i < count; i++)
{
row[i] = bn.Read(ts[i]);
}
rs.Add(row);
total++;
}
Rows = rs;
return total;
}
/// <summary>读取</summary>
/// <param name="pk"></param>
/// <returns></returns>
public Boolean Read(Packet pk)
{
if (pk == null || pk.Total == 0) return false;
Read(pk.GetStream());
return true;
}
/// <summary>从文件加载</summary>
/// <param name="file"></param>
/// <returns></returns>
public Int64 LoadFile(String file) => file.AsFile().OpenRead(s => Read(s));
#endregion
#region 二进制写入
/// <summary>写入数据流</summary>
/// <param name="stream"></param>
public Int64 Write(Stream stream)
{
var p = stream.Position;
var bn = new Binary
{
EncodeInt = true,
Stream = stream,
};
// 写入数据体
var rs = Rows;
Total = rs == null ? 0 : rs.Count;
// 写入头部
WriteHeader(bn);
// 写入数据行
WriteData(bn);
return stream.Position - p;
}
/// <summary>写入头部到数据流</summary>
/// <param name="bn"></param>
public void WriteHeader(Binary bn)
{
var cs = Columns;
var ts = Types;
// 头部,幻数、版本和压缩标记
bn.Write("NewLifeDbTable".GetBytes(), 0, 14);
bn.Write(_Ver);
bn.Write(0);
// 写入头部
var count = cs.Length;
bn.Write(count);
for (var i = 0; i < count; i++)
{
bn.Write(cs[i]);
bn.Write((Byte)ts[i].GetTypeCode());
}
// 数据行数
bn.Write(Total.GetBytes(), 0, 4);
}
/// <summary>写入数据部分到数据流</summary>
/// <param name="bn"></param>
public void WriteData(Binary bn)
{
var ts = Types;
var rs = Rows;
// 写入数据
foreach (var row in rs)
{
for (var i = 0; i < row.Length; i++)
{
bn.Write(row[i], ts[i]);
}
}
}
/// <summary>转数据包</summary>
/// <returns></returns>
public Packet ToPacket()
{
var ms = new MemoryStream
{
Position = 8
};
Write(ms);
ms.Position = 8;
return new Packet(ms);
}
/// <summary>保存到文件</summary>
/// <param name="file"></param>
/// <returns></returns>
public Int64 SaveFile(String file) => file.AsFile().OpenWrite(s => Write(s));
#endregion
#region 获取
/// <summary>读取指定行的字段值</summary>
/// <typeparam name="T"></typeparam>
/// <param name="row"></param>
/// <param name="name"></param>
/// <returns></returns>
public T Get<T>(Int32 row, String name)
{
if (!TryGet<T>(row, name, out var value)) return default(T);
return value;
}
/// <summary>尝试读取指定行的字段值</summary>
/// <typeparam name="T"></typeparam>
/// <param name="row"></param>
/// <param name="name"></param>
/// <param name="value"></param>
/// <returns></returns>
public Boolean TryGet<T>(Int32 row, String name, out T value)
{
value = default(T);
var rs = Rows;
if (row < 0 || row >= rs.Count || name.IsNullOrEmpty()) return false;
var col = GetColumn(name);
if (col < 0) return false;
value = rs[row][col].ChangeType<T>();
return true;
}
/// <summary>根据名称找字段序号</summary>
/// <param name="name"></param>
/// <returns></returns>
public Int32 GetColumn(String name)
{
var cs = Columns;
if (cs == null) return -1;
for (var i = 0; i < cs.Length; i++)
{
if (cs[i].EqualIgnoreCase(name)) return i;
}
return -1;
}
#endregion
#region 辅助
/// <summary>数据集</summary>
/// <returns></returns>
public override String ToString() => "DbTable[{0}][{1}]".F(Columns == null ? 0 : Columns.Length, Rows == null ? 0 : Rows.Count);
private static IDictionary<TypeCode, Object> _Defs;
private static Object GetDefault(TypeCode tc)
{
if (_Defs == null)
{
var dic = new Dictionary<TypeCode, Object>();
foreach (TypeCode item in Enum.GetValues(typeof(TypeCode)))
{
Object val = null;
switch (item)
{
case TypeCode.Boolean:
val = false;
break;
case TypeCode.Char:
val = (Char)0;
break;
case TypeCode.SByte:
val = (SByte)0;
break;
case TypeCode.Byte:
val = (Byte)0;
break;
case TypeCode.Int16:
val = (Int16)0;
break;
case TypeCode.UInt16:
val = (UInt16)0;
break;
case TypeCode.Int32:
val = 0;
break;
case TypeCode.UInt32:
val = (UInt32)0;
break;
case TypeCode.Int64:
val = (Int64)0;
break;
case TypeCode.UInt64:
val = (UInt64)0;
break;
case TypeCode.Single:
val = (Single)0;
break;
case TypeCode.Double:
val = (Double)0;
break;
case TypeCode.Decimal:
val = (Decimal)0;
break;
case TypeCode.DateTime:
val = DateTime.MinValue;
break;
case TypeCode.Empty:
case TypeCode.Object:
case TypeCode.DBNull:
case TypeCode.String:
default:
val = null;
break;
}
dic[item] = val;
}
_Defs = dic;
}
return _Defs[tc];
}
Object ICloneable.Clone() => Clone();
/// <summary>克隆</summary>
/// <returns></returns>
public DbTable Clone()
{
var dt = new DbTable
{
Columns = Columns,
Types = Types,
Rows = Rows,
Total = Total
};
return dt;
}
#endregion
#region 枚举
/// <summary>获取枚举</summary>
/// <returns></returns>
public IEnumerator<DbRow> GetEnumerator() => new DbEnumerator { Table = this };
IEnumerator IEnumerable.GetEnumerator() => GetEnumerator();
struct DbEnumerator : IEnumerator<DbRow>
{
public DbTable Table { get; set; }
private Int32 _row;
private DbRow _Current;
public DbRow Current => _Current;
Object IEnumerator.Current => _Current;
public Boolean MoveNext()
{
var rs = Table?.Rows;
if (rs == null || rs.Count == 0) return false;
if (_row < 0 || _row >= rs.Count)
{
_Current = default(DbRow);
return false;
}
_Current = new DbRow(Table, _row);
_row++;
return true;
}
public void Reset()
{
_Current = default(DbRow);
_row = -1;
}
public void Dispose() { }
}
#endregion
}
}
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