你可以构建自己的
CopyToDataTable,它可以处理任何类型的IEnumerable(不仅仅是
DataRow
),并返回一个新的
DataTable
:
// following would not compile by default
// because input is not an IEnumerable<DataRow> but an anonymous type
var tblResult = bmwCars.CopyToDataTable();
以下是实现代码(借助MSDN):
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;
public ObjectShredder() {
_type = typeof(T);
_fi = _type.GetFields();
_pi = _type.GetProperties();
_ordinalMap = new Dictionary<string, int>();
}
public DataTable Shred(IEnumerable<T> source, DataTable table, LoadOption? options) {
if (typeof(T).IsPrimitive) {
return ShredPrimitive(source, table, options);
}
if (table == null) {
table = new DataTable(typeof(T).Name);
}
table = ExtendTable(table, typeof(T));
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 table;
}
public DataTable ShredPrimitive(IEnumerable<T> source, DataTable table, LoadOption? options) {
if (table == null) {
table = new DataTable(typeof(T).Name);
}
if (!table.Columns.Contains("Value")) {
table.Columns.Add("Value", typeof(T));
}
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 table;
}
public object[] ShredObject(DataTable table, T instance) {
FieldInfo[] fi = _fi;
PropertyInfo[] pi = _pi;
if (instance.GetType() != typeof(T)) {
ExtendTable(table, instance.GetType());
fi = instance.GetType().GetFields();
pi = instance.GetType().GetProperties();
}
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 values;
}
public DataTable ExtendTable(DataTable table, Type type) {
foreach (FieldInfo f in type.GetFields()) {
if (!_ordinalMap.ContainsKey(f.Name)) {
DataColumn dc = table.Columns.Contains(f.Name) ? table.Columns[f.Name]
: table.Columns.Add(f.Name, f.FieldType);
_ordinalMap.Add(f.Name, dc.Ordinal);
}
}
foreach (PropertyInfo p in type.GetProperties()) {
if (!_ordinalMap.ContainsKey(p.Name)) {
DataColumn dc = table.Columns.Contains(p.Name) ? table.Columns[p.Name]
: table.Columns.Add(p.Name, p.PropertyType);
_ordinalMap.Add(p.Name, dc.Ordinal);
}
}
return table;
}
}
现在您可以添加这些扩展:
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);
}
}
现在 CopyToDataTable
可以与任何类型的 IEnumerable<T>
一起使用了 :)