Linq to entities in asp.net and generic delete method - linq

Question

I am having trouble creating generic delete method, not even sure if this possible. I have a delete method which will delete record from db based on entity type and row id value (pk),
that works ok but it needs to know the type in advance. In some cases I can only get object
type using Object.GetType() at runtime (like from viewstate) and that is when trouble starts. Here is my method that works when type is known, is there a way to modify it so that it will use Object.GetType() instead of T ?
public void Delete<T>(long Id) where T : class,new()
{
#region PerformaneMonitor
IDbEntities Db=null;
T item=null;
try
{
Db = this.GetDatabase();
item = new T();
Type itemType = item.GetType();
EntityContainer entityContainer = Db.MetadataWorkspace.GetEntityContainer(Db.DefaultContainerName, DataSpace.CSpace);
var entity = entityContainer.BaseEntitySets.First(b => b.ElementType.Name == itemType.Name);
if (entity.ElementType.KeyMembers.Count == 0)
{
throw new Exception("Unable to delete a record witout unique id");
}
string PrimaryKeyName = entity.ElementType.KeyMembers[0].Name;
itemType.GetProperty(PrimaryKeyName).SetValue(item, Id, null);
}
catch (Exception ex)
{
Close(Db);
throw(ex);
}
this.Delete<T>(item, Db);
Close(Db);
#region PerformaneMonitor
}
so I am trying to convert it to Delete(object EntityType,long Id ) but no luck.
Here what it looks like :
public void Delete(object target,long Id)
{
#region PerformaneMonitor
IDbEntities Db = null;
try
{
Db = this.GetDatabase();
Type itemType = (Type)target;
EntityContainer entityContainer = Db.MetadataWorkspace.GetEntityContainer(Db.DefaultContainerName, DataSpace.CSpace);
var entity= entityContainer.BaseEntitySets.First(b => b.ElementType.Name == itemType.Name);
if (entity.ElementType.KeyMembers.Count == 0)
{
throw new Exception("Unable to delete a record witout unique id");
}
string PrimaryKeyName = entity.ElementType.KeyMembers[0].Name;
itemType.GetProperty(PrimaryKeyName).SetValue(target, Id, null);
}
catch (Exception ex)
{
Close(Db);
throw (ex);
}
this.Delete(target, Db);
Close(Db);
//_method_tag_end_
#region PerformaneMonitor
}
I am getting 'Object does not match target type' on
this line:
itemType.GetProperty(PrimaryKeyName).SetValue(target, pkey, null);
the object target is actaul instance of specific type which I do in the calling method from Type of object and using reflection and pass to this function but still I have no idea what type it is at run time.
If someone can help it will be greatly appreciated.

Answer 1

It sounds like you should do something along these lines: (Sorry, can't test to make sure it works as written.)
object o = itemType.GetProperty(PrimaryKeyName);
MethodInfo mi = o.GetType().GetMethod("SetValue");
mi.Invoke(o, new object [] { Id, null });