Comment convertir un DataTable en objet dynamique?
Comment puis-je convertir une DataTable en IEnumerable<dynamicObject>?
Par exemple, je veux convertir any DataTable
ID | Name DI | emaN
--------- or ---------
1 | x 2 | x
2 | y 1 | y
Dans une liste d'objets
// list 1 (ex 1) // list 2 (ex 2)
{ {
{ ID = 1, Name = "x" } { DI = 2, emaN = "x" }
{ ID = 2, Name = "y" } { DI = 1, emaN = "y" }
} }
Alors
list1.First().ID // 1
list2.First().emaN // "x"
Comment puis-je le faire?
Que diriez-vous de DynamicObject :
public static class DataTableX
{
public static IEnumerable<dynamic> AsDynamicEnumerable(this DataTable table)
{
// Validate argument here..
return table.AsEnumerable().Select(row => new DynamicRow(row));
}
private sealed class DynamicRow : DynamicObject
{
private readonly DataRow _row;
internal DynamicRow(DataRow row) { _row = row; }
// Interprets a member-access as an indexer-access on the
// contained DataRow.
public override bool TryGetMember(GetMemberBinder binder, out object result)
{
var retVal = _row.Table.Columns.Contains(binder.Name);
result = retVal ? _row[binder.Name] : null;
return retVal;
}
}
}
Vous pouvez également essayer de remplacer TrySetMember si vous souhaitez rendre la ligne dynamique accessible en écriture.
Utilisation :
DataTable table = ...
var dynamicTable = table.AsDynamicEnumerable();
var firstRowsNameField = dynamicTable.First().Name;
class Program
{
static void Main()
{
var dt = new DataTable();
dt.Columns.Add("ID", typeof(int));
dt.Columns.Add("Name", typeof(string));
dt.Rows.Add(1, "x");
dt.Rows.Add(2, "y");
List<dynamic> dynamicDt = dt.ToDynamic();
Console.WriteLine(dynamicDt.First().ID);
Console.WriteLine(dynamicDt.First().Name);
}
}
public static class DataTableExtensions
{
public static List<dynamic> ToDynamic(this DataTable dt)
{
var dynamicDt = new List<dynamic>();
foreach (DataRow row in dt.Rows)
{
dynamic dyn = new ExpandoObject();
dynamicDt.Add(dyn);
foreach (DataColumn column in dt.Columns)
{
var dic = (IDictionary<string, object>)dyn;
dic[column.ColumnName] = row[column];
}
}
return dynamicDt;
}
}
Les codes suneelsarraf précédents ne généraient que des objets dynamiques à l'exécution avec une propriété en tant que chaîne. Après la mise à jour générera chaque propriété en fonction du type de données de la colonne DataTable.
public static class DataTableExtension
{
/// <summary>
/// Convert a database data table to a runtime dynamic definied type collection (dynamic class' name as table name).
/// </summary>
/// <param name="dt"></param>
/// <param name="className"></param>
/// <returns></returns>
public static List<dynamic> ToDynamicList(DataTable dt, string className)
{
return ToDynamicList(ToDictionary(dt), getNewObject(dt.Columns, className));
}
private static List<Dictionary<string, object>> ToDictionary(DataTable dt)
{
var columns = dt.Columns.Cast<DataColumn>();
var Temp = dt.AsEnumerable().Select(dataRow => columns.Select(column =>
new { Column = column.ColumnName, Value = dataRow[column] })
.ToDictionary(data => data.Column, data => data.Value)).ToList();
return Temp.ToList();
}
private static List<dynamic> ToDynamicList(List<Dictionary<string, object>> list, Type TypeObj)
{
dynamic temp = new List<dynamic>();
foreach (Dictionary<string, object> step in list)
{
object Obj = Activator.CreateInstance(TypeObj);
PropertyInfo[] properties = Obj.GetType().GetProperties();
Dictionary<string, object> DictList = (Dictionary<string, object>)step;
foreach (KeyValuePair<string, object> keyValuePair in DictList)
{
foreach (PropertyInfo property in properties)
{
if (property.Name == keyValuePair.Key)
{
if (keyValuePair.Value != null && keyValuePair.Value.GetType() != typeof(System.DBNull))
{
if (keyValuePair.Value.GetType() == typeof(System.Guid))
{
property.SetValue(Obj, keyValuePair.Value, null);
}
else
{
property.SetValue(Obj, keyValuePair.Value, null);
}
}
break;
}
}
}
temp.Add(Obj);
}
return temp;
}
private static Type getNewObject(DataColumnCollection columns, string className)
{
AssemblyName assemblyName = new AssemblyName();
assemblyName.Name = "YourAssembly";
System.Reflection.Emit.AssemblyBuilder assemblyBuilder = Thread.GetDomain().DefineDynamicAssembly(assemblyName, AssemblyBuilderAccess.Run);
ModuleBuilder module = assemblyBuilder.DefineDynamicModule("YourDynamicModule");
TypeBuilder typeBuilder = module.DefineType(className, TypeAttributes.Public);
foreach (DataColumn column in columns)
{
string propertyName = column.ColumnName;
FieldBuilder field = typeBuilder.DefineField(propertyName, column.DataType, FieldAttributes.Public);
PropertyBuilder property = typeBuilder.DefineProperty(propertyName, System.Reflection.PropertyAttributes.None, column.DataType, new Type[] { column.DataType });
MethodAttributes GetSetAttr = MethodAttributes.Public | MethodAttributes.HideBySig;
MethodBuilder currGetPropMthdBldr = typeBuilder.DefineMethod("get_value", GetSetAttr, column.DataType, new Type[] { column.DataType }); // Type.EmptyTypes);
ILGenerator currGetIL = currGetPropMthdBldr.GetILGenerator();
currGetIL.Emit(OpCodes.Ldarg_0);
currGetIL.Emit(OpCodes.Ldfld, field);
currGetIL.Emit(OpCodes.Ret);
MethodBuilder currSetPropMthdBldr = typeBuilder.DefineMethod("set_value", GetSetAttr, null, new Type[] { column.DataType });
ILGenerator currSetIL = currSetPropMthdBldr.GetILGenerator();
currSetIL.Emit(OpCodes.Ldarg_0);
currSetIL.Emit(OpCodes.Ldarg_1);
currSetIL.Emit(OpCodes.Stfld, field);
currSetIL.Emit(OpCodes.Ret);
property.SetGetMethod(currGetPropMthdBldr);
property.SetSetMethod(currSetPropMthdBldr);
}
Type obj = typeBuilder.CreateType();
return obj;
}
}
Certains ORM peuvent lire directement de la base de données vers dynamic ExpandoObject. Par exemple petapoco (et lisez ici le exemple )
Ou vous pouvez essayer quelque chose de similaire:
var dt = new DataTable();
var dns = new List<dynamic>();
foreach (var item in dt.AsEnumerable())
{
// Expando objects are IDictionary<string, object>
IDictionary<string, object> dn = new ExpandoObject();
foreach (var column in dt.Columns.Cast<DataColumn>())
{
dn[column.ColumnName] = item[column];
}
dns.Add(dn);
}
// Now you can do something like dns[0].MyColumnName
// or recast to IDictionary<string, object> and do
// something like casted["MyColumnName"]
essayer
var MyResult = from x in MyDataTable select new { ID = x["ID"], Name = x["Name"] }.ToList ();
Vous pouvez utiliser une extension comme ceci:
using System;
using System.Collections.Generic;
using System.Data;
using System.Dynamic;
public static class DataTableExtensions
{
public static IEnumerable<dynamic> AsDynamicEnumerable(this DataTable table)
{
if (table == null)
{
yield break;
}
foreach (DataRow row in table.Rows)
{
IDictionary<string, object> dRow = new ExpandoObject();
foreach (DataColumn column in table.Columns)
{
var value = row[column.ColumnName];
dRow[column.ColumnName] = Convert.IsDBNull(value) ? null : value;
}
yield return dRow;
}
}
}
Utilisation:
var dataTable = GetDataTableFromSomewhere();
var dynamicTable = dataTable.AsDynamicEnumerable();
var firstRowIDColumn = dynamicTable.First().ID;
var lastRowIDColumn = dynamicTable.Last()["ID"];
Mais j'ai préféré une approche IDataReader si possible.
Convertir Datatable À la liste
#region "Convert DataTable to List<dynamic>"
public List<dynamic> ToDynamicList(DataTable dt)
{
List<string> cols = (dt.Columns.Cast<DataColumn>()).Select(column => column.ColumnName).ToList();
return ToDynamicList(ToDictionary(dt), getNewObject(cols));
}
public List<Dictionary<string, object>> ToDictionary(DataTable dt)
{
var columns = dt.Columns.Cast<DataColumn>();
var Temp = dt.AsEnumerable().Select(dataRow => columns.Select(column =>
new { Column = column.ColumnName, Value = dataRow[column] })
.ToDictionary(data => data.Column, data => data.Value)).ToList();
return Temp.ToList();
}
public List<dynamic> ToDynamicList(List<Dictionary<string, object>> list, Type TypeObj)
{
dynamic temp = new List<dynamic>();
foreach (Dictionary<string, object> step in list)
{
object Obj = Activator.CreateInstance(TypeObj);
PropertyInfo[] properties = Obj.GetType().GetProperties();
Dictionary<string, object> DictList = (Dictionary<string, object>)step;
foreach (KeyValuePair<string, object> keyValuePair in DictList)
{
foreach (PropertyInfo property in properties)
{
if (property.Name == keyValuePair.Key)
{
property.SetValue(Obj, keyValuePair.Value.ToString(), null);
break;
}
}
}
temp.Add(Obj);
}
return temp;
}
private Type getNewObject(List<string> list)
{
AssemblyName assemblyName = new AssemblyName();
assemblyName.Name = "tmpAssembly";
AssemblyBuilder assemblyBuilder = Thread.GetDomain().DefineDynamicAssembly(assemblyName, AssemblyBuilderAccess.Run);
ModuleBuilder module = assemblyBuilder.DefineDynamicModule("tmpModule");
TypeBuilder typeBuilder = module.DefineType("WebgridRowCellCollection", TypeAttributes.Public);
foreach (string step in list)
{
string propertyName = step;
FieldBuilder field = typeBuilder.DefineField(propertyName, typeof(string), FieldAttributes.Public);
PropertyBuilder property = typeBuilder.DefineProperty(propertyName, System.Reflection.PropertyAttributes.None, typeof(string), new Type[] { typeof(string) });
MethodAttributes GetSetAttr = MethodAttributes.Public | MethodAttributes.HideBySig;
MethodBuilder currGetPropMthdBldr = typeBuilder.DefineMethod("get_value", GetSetAttr, typeof(string), Type.EmptyTypes);
ILGenerator currGetIL = currGetPropMthdBldr.GetILGenerator();
currGetIL.Emit(OpCodes.Ldarg_0);
currGetIL.Emit(OpCodes.Ldfld, field);
currGetIL.Emit(OpCodes.Ret);
MethodBuilder currSetPropMthdBldr = typeBuilder.DefineMethod("set_value", GetSetAttr, null, new Type[] { typeof(string) });
ILGenerator currSetIL = currSetPropMthdBldr.GetILGenerator();
currSetIL.Emit(OpCodes.Ldarg_0);
currSetIL.Emit(OpCodes.Ldarg_1);
currSetIL.Emit(OpCodes.Stfld, field);
currSetIL.Emit(OpCodes.Ret);
property.SetGetMethod(currGetPropMthdBldr);
property.SetSetMethod(currSetPropMthdBldr);
}
Type obj = typeBuilder.CreateType();
return obj;
}
#endregion