如何解决如何使用多个主键表动态创建 DevExpress XPO？
但它只适用于单个主键表。所以我搜索了更多发现这个： https://github.com/DevExpress-Examples/XPO_how-to-create-persistent-classes-mapped-to-tables-with-a-composite-primary-key-at-runtime-e4606
但是有很大的不同，我认为它不满足，因为它谈到了复合键（一个键有很多列） 所以我只需要一个从 SQL -Server 表动态创建 XPO 的例子： 我的表架构如下
XPOCollectionSource 然后在服务器模式下绑定到网格……这就是我所需要的。
我使用的代码
XPServerCollectionSource GetServerModeSourceForTable(IDbConnection connection,string tableName) {
XPDictionary dict = new ReflectionDictionary();
XPClassInfo classInfo = dict.CreateClass(dict.QueryClassInfo(typeof(LiteDataObject)),tableName);
DBTable[] tables = ((ConnectionProviderSql)XpoDefault.GetConnectionProvider(connection,AutoCreateOption.None)).GetStorageTables(tableName);
foreach (DBColumn col in tables[0].Columns) {
XPMemberInfo member = classInfo.CreateMember(col.Name,DBColumn.GetType(
col.ColumnType));
if (tables[0].PrimaryKey.Columns.Contains(col.Name))
member.AddAttribute(new KeyAttribute());
}
return new XPServerCollectionSource(new Session(XpoDefault.GetDataLayer(
connection,dict,AutoCreateOption.None)),classInfo);
}
一目了然。如何将 XPServerCollectionSource 与动态创建的 XPO 对象一起使用。有两个主键。
解决方法
这是一个必须使用的类。谁需要更多细节。我可以免费帮助他。
实现可以是这样的：
[NonPersistent]
public class XPDynamicObject : XPLiteObject
{
public XPDynamicObject(Session session) : base(session) {}
public XPDynamicObject(Session session,XPClassInfo classInfo) : base(session,classInfo) { }
}
Button_Click or any event :
XPDynamicObject.AutoSaveOnEndEdit = false;
ReflectionDictionary dic = new ReflectionDictionary();
var classInfo = dic.CreateClass(dic.GetClassInfo(typeof(XPDynamicObject)),"general.users");
// WE MUST get schema from database .... via ConnectionProviderSql this is only way
var provider = XpoDefault.GetConnectionProvider(MSSqlConnectionProvider.GetConnectionString("(local)","testdb"),AutoCreateOption.None) as ConnectionProviderSql;
// Composite Key - this is only way to add composite key dynamically
XPComplexCustomMemberInfo user_key = new
XPComplexCustomMemberInfo(classInfo,"user_key",typeof(object),new KeyAttribute(),new PersistentAttribute(),new BrowsableAttribute(false));
user_key.AddSubMember("user_brn",typeof(int),new PersistentAttribute("user_brn"));
user_key.AddSubMember("user_num",new PersistentAttribute("user_num"));
var user_name = classInfo.CreateMember("user_name",typeof(string));
user_name.AddAttribute(new PersistentAttribute("user_name"));
dal = new SimpleDataLayer(dic,provider);
XPServerCollectionSource xpServerCollectionSource = new XPServerCollectionSource(session,classInfo); // XPServerCollectionSource Only Editable server-mode datasource via ALlowNew,AllowEdit,AllowRemove properties
GridControl.DataSource = xpServerCollectionSource ;
完整备忘单（设计时和运行时 XPO）
要按键或条件搜索对象，请使用以下内容：
编辑：2021-05-24
对于那些询问具有复合键的关联的人。它真的是噩梦。默认情况下，Xpo 不提供。相反，您可以在子类中使用 Session.GetObjectByKey() 并在父类中使用新的 XPCollection。但实际上它有点慢，使用人工密钥的本地方式。
一目了然：使用人工/单键列来改善任何 ORM 兼容性。否则以后在数据库中将是噩梦。如果 例如，您支持另一个或替换当前的 ORM。
这是与复合键关联的代码。 （请注意，您需要像上图一样动态转换它。您可能需要创建自定义 XPMemberInfo 并覆盖 GetValue() 以返回 Session.GetObjectByKey() 并创建新的 XPCollection。曾经是 Xpo。所以从技术上讲，复合键是不好的方式，除非您需要创建单表将其绑定到网格。例如：- SalesOrderDetail 表没有更多子表）
[Persistent("users")]
public class user : XPLiteObject
{
public user(Session session) : base(session) { }
public user(Session session,classInfo) { }
[Key,Persistent]
public user_key user_key { get; set; }
[Persistent("user_name")]
public string user_name { get; set; }
private XPCollection<Trans> _trans;
public XPCollection<Trans> trans
{
get
{
if (_trans == null)
_trans = new XPCollection<Trans>(Session,CriteriaOperator.Parse($"user_brn = {user_key.user_brn} AND user_num = {user_key.user_num}"));
return _trans;
}
}
}
public class Trans : XPLiteObject
{
public Trans(Session session) : base(session) { }
public Trans(Session session,Persistent("TransID")]
public int TransID { get; set; }
public int user_brn { get; set; }
public int user_num { get; set; }
public user user
{
get
{
var key = new user_key();
key.user_brn = 1;
key.user_num = 3;
var obj = Session.GetObjectByKey<user>(key,true);
return obj;
}
}
}
// Composite-Key
public struct user_key
{
[Persistent("user_brn")]
public int user_brn { get; set; }
[Persistent("user_num")]
public int user_num { get; set; }
}
来自上述模型的动态运行时版本：
class XPCompositeAssociationMemberInfo : XPCustomMemberInfo
{
public XPCompositeAssociationMemberInfo(XPClassInfo owner,string propertyName,Type propertyType,XPClassInfo referenceType,bool nonPersistent,bool nonPublic) : base(owner,propertyName,propertyType,referenceType,nonPersistent,nonPublic)
{
}
public override object GetValue(object theObject)
{
XPDynamicObject val = theObject as XPDynamicObject;
if(val != null)
{
var user_num = val.GetMemberValue("user_num");
IdList vals = new IdList();
vals.Add(1);
vals.Add(user_num);
return val.Session.GetObjectByKey(ReferenceType,vals);
}
return val;
}
}
XPDynamicObject.AutoSaveOnEndEdit = false;
ReflectionDictionary dic = new ReflectionDictionary();
var userClassInfo = dic.CreateClass(dic.GetClassInfo(typeof(XPDynamicObject)),"users");
// WE MUST get schema from database .... via ConnectionProviderSql this is only way
var provider = XpoDefault.GetConnectionProvider(MSSqlConnectionProvider.GetConnectionString("(local)",AutoCreateOption.None) as ConnectionProviderSql;
//DBTable Table = provider.GetStorageTables("users")[0];
// Composite Key - this is only way to add composite key dynamically
XPComplexCustomMemberInfo user_key = new XPComplexCustomMemberInfo(userClassInfo,new PersistentAttribute("user_num"));
var user_name = userClassInfo.CreateMember("user_name",typeof(string));
user_name.AddAttribute(new PersistentAttribute("user_name"));
var transClassInfo = dic.CreateClass(dic.GetClassInfo(typeof(XPDynamicObject)),"Trans");
var TransID = transClassInfo.CreateMember("TransID",new KeyAttribute());
var user_brn = transClassInfo.CreateMember("user_brn",typeof(int));
var user_num = transClassInfo.CreateMember("user_num",typeof(int));
XPCompositeAssociationMemberInfo userMI = new XPCompositeAssociationMemberInfo(transClassInfo,"user",userClassInfo,true,false);
dal = new SimpleDataLayer(dic,provider);
Session session = new Session(dal);
XPServerCollectionSource xpServerCollectionSource = new XPServerCollectionSource(session,transClassInfo); // XPServerCollectionSource Only Editable server-mode datasource via ALlowNew,AllowRemove properties
xpServerCollectionSource.DisplayableProperties = "TransID;user.user_key.user_num;user.user_name";
最后，重要的！
在运行时实现复合键的情况真的非常非常困难 在任何 Xpo 中。而是替换为 Single Column Key(Identity or 人造的。 GUID 一等）
,我不知道这是否是您想要的，但我会使用 XPInstantFeedbackSource 分享我的代码。
您可以在 How To Implement The Instant Feedback Mode Xpo
获得更多信息
XPLiteObject LogXPOModel
[Persistent("log.t_log")]
public class LogXPOModel : XPLiteObject
{
[Key,DevExpress.Xpo.DisplayName("id")]
public long id { get; set; }
[Key,DevExpress.Xpo.DisplayName("recv_time")]
public long recv_time
...
}
Window 主窗口
public class MainWindow : Window
{
public XPInstantFeedbackSource SqliteXPInstantFeedbackSource
public MainWindow() {
...
SqliteXPInstantFeedbackSource = new XPInstantFeedbackSource();
SqliteXPInstantFeedbackSource.ObjectType = typeof(LogXPOModel);
SqliteXPInstantFeedbackSource.ResolveSession += SqliteXPInstantFeedbackSource_ResolveSession;
SqliteXPInstantFeedbackSource.DismissSession += SqliteXPInstantFeedbackSource_DismissSession;
View.Grid.ItemsSource = SqliteXPInstantFeedbackSource;
}
...
}
就像那样——我的桌子有两把钥匙；而且，它不会产生任何问题。
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