C# 期权); } 其他的 { table.LoadDataRow(值,true); } } } table.EndLoadData(); //把桌子还给我。 返回表; } 公共对象[]ShredObject(数据表,T实例) { FieldInfo[]fi=\
期权); } 其他的 { table.LoadDataRow(值,true); } } } table.EndLoadData(); //把桌子还给我。 返回表; } 公共对象[]ShredObject(数据表,T实例) { FieldInfo[]fi=\u-fi; PropertyInfo[]pi=\u pi; if(instance.GetType()!=typeof(T)) { //如果实例是从T派生的,则扩展表架构 //并获取属性和字段。 可扩展(表,实例.GetType()); fi=instance.GetType().GetFields(); pi=instance.GetType().GetProperties(); } //将实例的属性和字段值添加到数组中。 Object[]value=新对象[table.Columns.Count]; foreach(fi中的字段信息f) { 值[_ordinalMap[f.Name]]=f.GetValue(实例); } foreach(以pi表示的p属性) { 值[_ordinalMap[p.Name]]=p.GetValue(实例,null); } //返回实例的属性和字段值。 返回值; } 公共数据表可扩展(数据表,类型) { //如果输入表为null或值为 //在序列中,由T型派生而来。 foreach(type.GetFields()中的FieldInfo f) { 如果(!_ordinalMap.ContainsKey(f.Name)) { //如果字段不存在,则将其作为列添加到表中 //已经。 DataColumn dc=table.Columns.Contains(f.Name)?table.Columns[f.Name] :table.Columns.Add(f.Name,f.FieldType); //将字段添加到序号映射。 _序号映射添加(f.名称,dc.序号); } } foreach(type.GetProperties()中的PropertyInfo p) { 如果(!_ordinalMap.ContainsKey(p.Name)) { //如果该属性不存在,请将其作为列添加到表中 //已经。 DataColumn dc=table.Columns.Contains(p.Name)?table.Columns[p.Name] :table.Columns.Add(p.Name,p.PropertyType); //将属性添加到序号映射。 _序号映射添加(p.Name,dc.Ordinal); } } //把桌子还给我。 返回表; } } /// ///直接从中复制的代码http://msdn.microsoft.com/en-us/library/bb669096.aspx /// 公共静态类CustomLINQtoDataSetMethods { 公共静态数据表CopyToDataTable(此IEnumerable源) { 返回新的ObjectShreder().Shred(source,null,null); } 公共静态数据表CopyToDataTable(此IEnumerable源, 数据表,加载选项?选项) { 返回新的ObjectShreder().Shred(源、表、选项); } }C# 期权); } 其他的 { table.LoadDataRow(值,true); } } } table.EndLoadData(); //把桌子还给我。 返回表; } 公共对象[]ShredObject(数据表,T实例) { FieldInfo[]fi=\,c#,linq,datatable,pivot,C#,Linq,Datatable,Pivot,期权); } 其他的 { table.LoadDataRow(值,true); } } } table.EndLoadData(); //把桌子还给我。 返回表; } 公共对象[]ShredObject(数据表,T实例) { FieldInfo[]fi=\u-fi; PropertyInfo[]pi=\u pi; if(instance.GetType()!=typeof(T)) { //如果实例是从T派生的,则扩展表架构 //并获取属性和字段。 可扩展(表,实例.GetType()); fi=
你能发布你得到的输出吗?所以我运行了这段代码,它执行并打印预期的结果。我已经修改了答案,使之成为一个完全可编译且可执行的程序。哇,谢谢,我希望我可以避免使用那个怪物方法的MSDN文章,因为我一点也不了解它,但这将暂时起作用,直到我能想出一个更好的方法为止。这是一个很棒的解决方案。我想处理的一个测试是,是否缺少一列。例如,下面的数据:
addRow(dt,“foo”,“bar”,“a”,“w”);addRow(dt,“foo”,“bar”,“c”,“y”);addRow(dt,“foo”,“bar”,“d”,“z”);addRow(dt,“foo”,“test”,“a”,“i”);addRow(dt,“foo”,“test”,“c”,“k”);addRow(dt,“foo”,“test”,“d”,“l”)代码>
ObjectName | ColumnName | Property | Value
----------------------------------------------
foo | bar | a | w
foo | bar | b | x
foo | bar | c | y
foo | bar | d | z
foo | test | a | i
foo | test | b | j
foo | test | c | k
foo | test | d | l
ObjectName | ColumnName | a | b | c | d
---------------------------------------------------
foo | bar | w | x | y | z
foo | test | i | j | k | l
var query = dt.AsEnumerable()
.GroupBy(row => row.Field<string>("ColumnName"))
.Select(g => new {
ColumnName = g.Key,
a = g.Where(row => row.Field<string>("Property") == "a").Select(c => c.Field<string>("Value")),
b = g.Where(row => row.Field<string>("Property") == "b").Select(c => c.Field<string>("Value")),
c = g.Where(row => row.Field<string>("Property") == "c").Select(c => c.Field<string>("Value")),
d = g.Where(row => row.Field<string>("Property") == "d").Select(c => c.Field<string>("Value"))
});
DataTable newDT = query.CopyToDataTable();
class Program
{
//Helper method to make the Select cleaner:
private static string GetProperty(IEnumerable<DataRow> rows, string propertyName)
{
return rows
.Where(row => row.Field<string>("Property") == propertyName)
.Select(c => c.Field<string>("Value"))
.FirstOrDefault();
}
//helper method for populating the datatable
private static void addRow(DataTable dt, string objectName, string columnName
, string property, string value)
{
var row = dt.NewRow();
row["ObjectName"] = objectName;
row["ColumnName"] = columnName;
row["Property"] = property;
row["Value"] = value;
dt.Rows.Add(row);
}
public static void Main(string[] args)
{
DataTable dt = new DataTable();
dt.Columns.Add("ObjectName");
dt.Columns.Add("ColumnName");
dt.Columns.Add("Property");
dt.Columns.Add("Value");
addRow(dt, "foo", "bar", "a", "w");
addRow(dt, "foo", "bar", "b", "x");
addRow(dt, "foo", "bar", "c", "y");
addRow(dt, "foo", "bar", "d", "z");
addRow(dt, "foo", "test", "a", "i");
addRow(dt, "foo", "test", "b", "j");
addRow(dt, "foo", "test", "c", "k");
addRow(dt, "foo", "test", "d", "l");
var query = dt.AsEnumerable()
.GroupBy(row => new
{
ObjectName = row.Field<string>("ObjectName"),
ColumnName = row.Field<string>("ColumnName")
})
.Select(g => new
{
ObjectName = g.Key.ObjectName,
ColumnName = g.Key.ColumnName,
a = GetProperty(g, "a"),
b = GetProperty(g, "b"),
c = GetProperty(g, "c"),
d = GetProperty(g, "d"),
})
.CopyToDataTable();
foreach (DataRow row in query.Rows)
{
foreach (DataColumn column in query.Columns)
{
System.Console.Write(row[column] + "\t");
}
System.Console.WriteLine();
}
Console.WriteLine("Press any key to exit. . .");
Console.ReadKey(true);
}
}
using System;
using System.Data;
using System.Collections.Generic;
using System.Reflection;
/// <summary>
/// Code copied directly from http://msdn.microsoft.com/en-us/library/bb669096.aspx
/// </summary>
/// <typeparam name="T"></typeparam>
public class ObjectShredder<T>
{
private System.Reflection.FieldInfo[] _fi;
private System.Reflection.PropertyInfo[] _pi;
private System.Collections.Generic.Dictionary<string, int> _ordinalMap;
private System.Type _type;
// ObjectShredder constructor.
public ObjectShredder()
{
_type = typeof(T);
_fi = _type.GetFields();
_pi = _type.GetProperties();
_ordinalMap = new Dictionary<string, int>();
}
/// <summary>
/// Loads a DataTable from a sequence of objects.
/// </summary>
/// <param name="source">The sequence of objects to load into the DataTable.</param>
/// <param name="table">The input table. The schema of the table must match that
/// the type T. If the table is null, a new table is created with a schema
/// created from the public properties and fields of the type T.</param>
/// <param name="options">Specifies how values from the source sequence will be applied to
/// existing rows in the table.</param>
/// <returns>A DataTable created from the source sequence.</returns>
public DataTable Shred(IEnumerable<T> source, DataTable table, LoadOption? options)
{
// Load the table from the scalar sequence if T is a primitive type.
if (typeof(T).IsPrimitive)
{
return ShredPrimitive(source, table, options);
}
// Create a new table if the input table is null.
if (table == null)
{
table = new DataTable(typeof(T).Name);
}
// Initialize the ordinal map and extend the table schema based on type T.
table = ExtendTable(table, typeof(T));
// Enumerate the source sequence and load the object values into rows.
table.BeginLoadData();
using (IEnumerator<T> e = source.GetEnumerator())
{
while (e.MoveNext())
{
if (options != null)
{
table.LoadDataRow(ShredObject(table, e.Current), (LoadOption)options);
}
else
{
table.LoadDataRow(ShredObject(table, e.Current), true);
}
}
}
table.EndLoadData();
// Return the table.
return table;
}
public DataTable ShredPrimitive(IEnumerable<T> source, DataTable table, LoadOption? options)
{
// Create a new table if the input table is null.
if (table == null)
{
table = new DataTable(typeof(T).Name);
}
if (!table.Columns.Contains("Value"))
{
table.Columns.Add("Value", typeof(T));
}
// Enumerate the source sequence and load the scalar values into rows.
table.BeginLoadData();
using (IEnumerator<T> e = source.GetEnumerator())
{
Object[] values = new object[table.Columns.Count];
while (e.MoveNext())
{
values[table.Columns["Value"].Ordinal] = e.Current;
if (options != null)
{
table.LoadDataRow(values, (LoadOption)options);
}
else
{
table.LoadDataRow(values, true);
}
}
}
table.EndLoadData();
// Return the table.
return table;
}
public object[] ShredObject(DataTable table, T instance)
{
FieldInfo[] fi = _fi;
PropertyInfo[] pi = _pi;
if (instance.GetType() != typeof(T))
{
// If the instance is derived from T, extend the table schema
// and get the properties and fields.
ExtendTable(table, instance.GetType());
fi = instance.GetType().GetFields();
pi = instance.GetType().GetProperties();
}
// Add the property and field values of the instance to an array.
Object[] values = new object[table.Columns.Count];
foreach (FieldInfo f in fi)
{
values[_ordinalMap[f.Name]] = f.GetValue(instance);
}
foreach (PropertyInfo p in pi)
{
values[_ordinalMap[p.Name]] = p.GetValue(instance, null);
}
// Return the property and field values of the instance.
return values;
}
public DataTable ExtendTable(DataTable table, Type type)
{
// Extend the table schema if the input table was null or if the value
// in the sequence is derived from type T.
foreach (FieldInfo f in type.GetFields())
{
if (!_ordinalMap.ContainsKey(f.Name))
{
// Add the field as a column in the table if it doesn't exist
// already.
DataColumn dc = table.Columns.Contains(f.Name) ? table.Columns[f.Name]
: table.Columns.Add(f.Name, f.FieldType);
// Add the field to the ordinal map.
_ordinalMap.Add(f.Name, dc.Ordinal);
}
}
foreach (PropertyInfo p in type.GetProperties())
{
if (!_ordinalMap.ContainsKey(p.Name))
{
// Add the property as a column in the table if it doesn't exist
// already.
DataColumn dc = table.Columns.Contains(p.Name) ? table.Columns[p.Name]
: table.Columns.Add(p.Name, p.PropertyType);
// Add the property to the ordinal map.
_ordinalMap.Add(p.Name, dc.Ordinal);
}
}
// Return the table.
return table;
}
}
/// <summary>
/// Code copied directly from http://msdn.microsoft.com/en-us/library/bb669096.aspx
/// </summary>
public static class CustomLINQtoDataSetMethods
{
public static DataTable CopyToDataTable<T>(this IEnumerable<T> source)
{
return new ObjectShredder<T>().Shred(source, null, null);
}
public static DataTable CopyToDataTable<T>(this IEnumerable<T> source,
DataTable table, LoadOption? options)
{
return new ObjectShredder<T>().Shred(source, table, options);
}
}