使用多个排序条件对 System.Data.DataTable 进行排序
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【中文标题】使用多个排序条件对 System.Data.DataTable 进行排序【英文标题】：Sort System.Data.DataTable with multiple sort criteria 【发布时间】：2020-08-02 18:20:59 【问题描述】：我有这个System.Data.DataTable：
DataTable dt = new DataTable();
dt.Columns.Add("Sector", typeof(string));
dt.Columns.Add("BBG IPC", typeof(double));
dt.Columns.Add("Analyst", typeof(string));
dt.Columns.Add("Issuer Group", typeof(string));
dt.Columns.Add("Seniority", typeof(string));
dt.Columns.Add("Mkt Value", typeof(double));
dt.Columns.Add("Nom Value", typeof(double));
dt.Columns.Add("Issue Group Rating", typeof(string));
dt.Columns.Add("Current SBR", typeof(string));
dt.Columns.Add("Notches", typeof(int));
dt.Columns.Add("Forward SBR", typeof(string));
dt.Columns.Add("Probability of Downgrade", typeof(string));
dt.Columns.Add("Risk Category", typeof(string));
dt.Columns.Add("Comment", typeof(string));
dt.Columns.Add("Restricted Message", typeof(string));
dt.Rows.Add(new object[] "Agencies", 180969, "MUSTO", "Caisse des Depots", "Senior", 10114481, 1000000, "AA", "BB",-1, "YY", "Hight", "R1", "Comment", "gvbhjnnijnibj" );
dt.Rows.Add(new object[] "Agencies", 180969, "MUSTO", "Caisse des Depots", "Senior", 10114481, 1000000, "AA", "CC",2, "II", "Low", "R2", "Bergtrgrt", "Other" );
dt.Rows.Add(new object[] "Agencies", 180969, "MUSTO", "Caisse des Depots", "Senior", 10114481, 1000000, "AA", "EE",3, "LL", "Mid", "R1", "vggvbhjjnnjoioion", "ggvbhibniujbuhvg uvvugvghV" );
dt.Rows.Add(new object[] "Consumer", 180969, "MUSTO", "Caisse des Depots", "Senior", 10114481, 1000000, "AA", "OO",-1, "SS", "Higth", "R3", "vgvgyhvgvjhbkj", "bibhjbhjbjhb ubuyhbuyhb hbuhbuhbhb" );
dt.Rows.Add(new object[] "Energy", 180969, "MUSTO", "Caisse des Depots", "Senior", 10114481, 1000000, "AA", "PP",-2, "QQ","Higth", "R1", "ertyuiop", "tfcgvhb Uvugvugvuhvh" );
dt.Rows.Add(new object[] "Energy", 180969, "MUSTO", "Caisse des Depots", "Senior", 10114481, 1000000, "AA", "GG",-3, "FF", "Low", "R2", "gvgvgvvgfccfdxdxrtf xrtfvgh tdctfgv trcfygvh tcfyghv b ygvhb ", "ygvgubiujb" );
我需要根据这些规则对表格进行排序：
第一级：按字母顺序排列的扇区。
第二级：降级概率按以下顺序：高、中、低
第 3 级：按字母顺序排列的发行人组
我尝试过类似这样的dt.DefaultView.Sort("Sector", "Probability of Downgrade", "Issuer Group");，但不起作用。我该怎么做？谢谢！
【问题讨论】：
使用DataTable 是否有特定原因，而不是某种列表？通常它带来的痛苦多于收获，但当然也可能有原因:-)
您尝试过版本：DataView dv = dt.DefaultView; dv.Sort = "[Sector], [Probability of Downgrade], [Issuer Group]";，然后检查dv 变量吗？
为了解决第二个排序要求（高、中、低），您能否根据此列分配一个额外的数值？
【参考方案1】：
DataView.Sort 属性的语法与 SQL Server 中使用的语法非常相似。
对于您的示例，您可以使用以下字符串：
dt.DefaultView.Sort = "Sector ASC, [Probability of Downgrade] ASC, [Issuer Group] ASC";
.. 然后只需在您的代码中访问 dt.DefaultView。
但您可能会遇到问题，因为（“High”、“Mid”、“Low”）的升序排序会将它们返回为“High”、“Low”、“Mid”。因为它们是字符串，所以它会按字母顺序进行。
如果源数据库中有概率，最简单的解决方案是使用概率的数字表示，并显示高/中/低但不按它们排序。
这是一个 LINQ 解决方法，如果您拥有的唯一数据选项是概率字符串：
// Make a dictionary to map your probability strings to integers.
var probLookup = new Dictionary<string, int>();
probLookup["High"] = 3;
probLookup["Mid"] = 2;
probLookup["Low"] = 1;
// Convert your DataTable into an array of a new type, that has the DataRow
// plus the three things you need to sort by, as separate properties.
var temp = dt.Select().Select(row => new()
Row = row,
Sector = row["Sector"],
// Map the downgrade prob. to an integer.
DowngradeProb = probLookup[(string) row["Probability of Downgrade"]],
IssuerGroup = row["Issuer Group"]
);
// Now, sort it by the 3 properties we created.
var temp2 = temp
.OrderBy(a => a.Sector)
.ThenByDesc(a => a.DowngradeProb)
.ThenBy(a => a.IssuerGroup);
// Now, fish out the Row again.
var temp3 = temp2.Select(a => a.Row).ToArray();
重要免责声明： LINQ 是凭记忆完成的：我不保证！
【讨论】：
谢谢你，安！但我不太了解如何解决“高、低、中”问题。 我的 LINQ 代码应该会处理它，但我同意这有点难以理解！我会重写一下。 好的，已更新。我将其更改为使用 Probability of Downgrade 字符串作为字典的键，该字典具有所需顺序的数值。然后我按 Sector、数值 和 IssuerGroup 对结果进行排序。最后，我创建了一个DataRow 对象数组，并将其分配给变量temp3，您可以对它做任何您需要做的事情。【参考方案2】：
尝试以下与您上次请求类似的方法：
using System;
using System.Collections.Generic;
using System.Linq;
using System.Text;
using System.Data;
namespace ConsoleApplication11
class Program
static void Main(string[] args)
List<string> probabilityStr = new List<string>() "Hight", "Mid", "Low" ;
DataTable dt = new DataTable();
dt.Columns.Add("Sector", typeof(string)); //1
dt.Columns.Add("BBG IPC", typeof(double));
dt.Columns.Add("Analyst", typeof(string));
dt.Columns.Add("Issuer Group", typeof(string)); //3
dt.Columns.Add("Seniority", typeof(string));
dt.Columns.Add("Mkt Value", typeof(double));
dt.Columns.Add("Nom Value", typeof(double));
dt.Columns.Add("Issue Group Rating", typeof(string));
dt.Columns.Add("Current SBR", typeof(string));
dt.Columns.Add("Notches", typeof(int));
dt.Columns.Add("Forward SBR", typeof(string));
dt.Columns.Add("Probability of Downgrade", typeof(string)); //2
dt.Columns.Add("Risk Category", typeof(string));
dt.Columns.Add("Comment", typeof(string));
dt.Columns.Add("Restricted Message", typeof(string));
dt.Rows.Add(new object[] "Agencies", 180969, "MUSTO", "Caisse des Depots", "Senior", 10114481, 1000000, "AA", "BB", -1, "YY", "Hight", "R1", "Comment", "gvbhjnnijnibj" );
dt.Rows.Add(new object[] "Agencies", 180969, "MUSTO", "Caisse des Depots", "Senior", 10114481, 1000000, "AA", "CC", 2, "II", "Low", "R2", "Bergtrgrt", "Other" );
dt.Rows.Add(new object[] "Agencies", 180969, "MUSTO", "Caisse des Depots", "Senior", 10114481, 1000000, "AA", "EE", 3, "LL", "Mid", "R1", "vggvbhjjnnjoioion", "ggvbhibniujbuhvg uvvugvghV" );
dt.Rows.Add(new object[] "Consumer", 180969, "MUSTO", "Caisse des Depots", "Senior", 10114481, 1000000, "AA", "OO", -1, "SS", "Higth", "R3", "vgvgyhvgvjhbkj", "bibhjbhjbjhb ubuyhbuyhb hbuhbuhbhb" );
dt.Rows.Add(new object[] "Energy", 180969, "MUSTO", "Caisse des Depots", "Senior", 10114481, 1000000, "AA", "PP", -2, "QQ", "Higth", "R1", "ertyuiop", "tfcgvhb Uvugvugvuhvh" );
dt.Rows.Add(new object[] "Energy", 180969, "MUSTO", "Caisse des Depots", "Senior", 10114481, 1000000, "AA", "GG", -3, "FF", "Low", "R2", "gvgvgvvgfccfdxdxrtf xrtfvgh tdctfgv trcfygvh tcfyghv b ygvhb ", "ygvgubiujb" );
DataTable dt2 = dt.Clone();
var sectors = dt.AsEnumerable()
.OrderBy(x => x.Field<string>("Sector"))
.ThenBy(x => probabilityStr.IndexOf(x.Field<string>("Probability of Downgrade")))
.ThenBy(x => x.Field<string>("Issuer Group"))
.GroupBy(x => x.Field<string>("Sector"))
.ToList();
for (int si = 0; si < sectors.Count(); si++)
var probabilities = sectors[si].GroupBy(x => x.Field<string>("Probability of Downgrade")).ToList();
for (int pi = 0; pi < probabilities.Count(); pi++)
var groups = probabilities[pi].GroupBy(x => x.Field<string>("Issuer Group")).ToList();
for (int gr = 0; gr < groups.Count(); gr++)
for (int r = 0; r < groups[gr].Count(); r++)
DataRow row = dt2.Rows.Add();
for (int i = 0; i < dt2.Columns.Count; i++)
switch (dt2.Columns[i].ColumnName)
case "Sector" :
if (pi == 0)
row["Sector"] = sectors[si].Key;
else
row["Sector"] = DBNull.Value;
break;
case "Probability of Downgrade" :
if (gr == 0)
row["Probability of Downgrade"] = probabilities[pi].Key;
else
row["Probability of Downgrade"] = DBNull.Value;
break;
case "Issuer Group" :
if (r == 0)
row["Issuer Group"] = groups[gr].Key;
else
row["Issuer Group"] = DBNull.Value;
break;
default :
row[i] = groups[r].First()[dt2.Columns[i].ColumnName];
break;
【讨论】：
有必要像你在“dt2”中那样改变列的顺序吗？因为在这种情况下，我需要保持与“dt”中完全相同的列顺序和结构。谢谢 我假设您首先想要分组列，就像您的屏幕截图一样。 但是在这段代码之后，扇区只在第一次出现时出现。我需要它出现在所有行中，因为稍后我需要按扇区进行其他提取。我试图删除 row["Sector"] = DBNull.Value;但它是一样的。我该怎么办？ 去掉 If 语句，只剩下 row["Sector"] = sector[si].Key;以上是关于使用多个排序条件对 System.Data.DataTable 进行排序的主要内容，如果未能解决你的问题，请参考以下文章