DataTableHelp.cs
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using System;
using System.Collections;
using System.Collections.Generic;
using System.ComponentModel.DataAnnotations;
using System.ComponentModel;
using System.Data;
using System.IO;
using System.Linq;
using System.Reflection;
using System.Web;
using System.Xml.Serialization;
namespace Hh.Mes.Common.DataTableTo
{
/// <summary>
/// DataTableHelp 的摘要说明
/// </summary>
public static class DataTableHelp
{
/// <summary>
/// 获取某一列的所有值 (字符串拼接手动 string.Join(",", x))
/// </summary>
/// <typeparam name="T">列数据类型</typeparam>
/// <param name="dtSource">数据表</param>
/// <param name="filedName">列名</param>
/// <returns></returns>
public static List<T> GetColumnValues<T>(this DataTable dtSource, string filedName)
{
return (from r in dtSource.AsEnumerable() select r.Field<T>(filedName)).ToList();
}
/// <summary>
/// 去重复数据方法
/// </summary>
public static DataTable Distinct(this DataTable dtSource, params string[] filedNames)
{
return dtSource.DefaultView.ToTable(true, filedNames);
}
/// <summary>
/// dt判断是否为null 或者 行数是否为0,true是为空，false存在数据
/// </summary>
public static bool IsEmpty(this DataTable dt)
{
return dt == null || dt.Rows.Count <= 0;
}
/// <summary>
/// string 空返回0，
/// </summary>
public static string IsEmpty(this object val, string retVal = "")
{
if (val == null) return "";
var temp = val.ToString();
return string.IsNullOrEmpty(temp) ? retVal : temp;
}
/// <summary>
/// list转datatable DataTableHelp.ListToDt(list)
/// </summary>
/// <typeparam name="T"></typeparam>
/// <param name="collection"></param>
/// <returns></returns>
public static DataTable ListToDt<T>(IEnumerable<T> collection)
{
var props = typeof(T).GetProperties().Where(t => t.GetCustomAttribute(typeof(EditableAttribute)) == null);
var dt = new DataTable();
foreach (var item in props)
{
DataColumn dataColumn;
Type colType = item.PropertyType;
if (colType.IsGenericType && colType.GetGenericTypeDefinition() == typeof(Nullable<>))
{
colType = colType.GetGenericArguments()[0];
}
var attr = (DescriptionAttribute)item.GetCustomAttribute(typeof(DescriptionAttribute));
if (attr != null)
{
dataColumn = new DataColumn(attr.Description, colType);
}
else
{
dataColumn = new DataColumn(item.Name, colType);
}
dt.Columns.Add(dataColumn);
}
if (collection.Count() > 0)
{
for (int i = 0; i < collection.Count(); i++)
{
ArrayList tempList = new ArrayList();
foreach (PropertyInfo pi in props)
{
object obj = pi.GetValue(collection.ElementAt(i), null);
tempList.Add(obj);
}
object[] array = tempList.ToArray();
dt.LoadDataRow(array, true);
}
}
return dt;
}
public static dynamic CalculateSumTime(this DataTable dtSource, string filterColumn, string sumColumn, dynamic filterValue)
{
// 使用 Select 方法查询指定列等于指定值的所有行
var rows = dtSource.AsEnumerable().Where(row => row.Field<dynamic>(filterColumn) == filterValue);
// 汇总指定列的值
dynamic totalSumTime = 0;
foreach (DataRow row in rows)
{
totalSumTime += row.Field<dynamic>(sumColumn);
}
return totalSumTime;
}
/// <summary>
/// 将DataTable的指定列转换为结构化字符串
/// </summary>
/// <param name="dataTable">数据源</param>
/// <param name="columnName">目标列名</param>
/// <param name="separator">分隔符（默认逗号）</param>
/// <param name="distinct">是否去重（默认否）</param>
public static string ConvertColumnToString(this DataTable dataTable, string columnName,
string separator = ",", bool distinct = true)
{
// 列存在性检查
if (!dataTable.Columns.Contains(columnName))
throw new ArgumentException($"列[{columnName}]不存在");
// 提取列值并处理空值
var query = dataTable.AsEnumerable()
.Select(row => row[columnName]?.ToString() ?? "")
.Cast<string>(); // 显式类型转换
// 去重逻辑
if (distinct)
query = (EnumerableRowCollection<string>)query.Distinct();
// 拼接为结构化字符串
return string.Join(separator, query);
}
}
}