protobuf网：抽象类的实例不能创建 [英] Protobuf-net: Instances of abstract classes cannot be created
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问题描述
根据代码在这里找到： http://stackoverflow.com/问题/ 923977 / protobuf的 - 和 - 的ListObject，如何对序列化，反序列化我创建了一个通用的ProtoDictionary有ProtoObject的值类型。
Based on the code found here: http://stackoverflow.com/questions/923977/protobuf-and-listobject-how-to-serialize-deserialize I've created a generic "ProtoDictionary" that has a value type of ProtoObject.
下面是我对ProtoDictionary代码：
Here is my code for the ProtoDictionary:
public class ProtoDictionary<TKey> : Dictionary<TKey, ProtoObject>
{
public void Add(TKey key, string value)
{
base.Add(key, new ProtoObject<<string>(value));
}
public void Add(TKey key, List<string> value)
{
base.Add(key, new ProtoObject<List<string>>(value));
}
public void Add(TKey key, List<UrlStatus> value)
{
base.Add(key, new ProtoObject<List<UrlStatus>>(value));
}
public void Add(TKey key, Dictionary<string, string> value)
{
base.Add(key, new ProtoObject<Dictionary<string, string>>(value));
}
public void Add(TKey key, Dictionary<string, int> value)
{
base.Add(key, new ProtoObject<Dictionary<string, int>>(value));
}
public void Add(TKey key, List<TrafficEntry> value)
{
base.Add(key, new ProtoObject<List<TrafficEntry>>(value));
}
public ProtoDictionary()
{
// Do nothing
}
// NOTE: For whatever reason, this class will not correctly deserialize without this method, even though
// the base class, Dictionary, has the SerializableAttribute. It's protected so only the framework can access it.
protected ProtoDictionary(SerializationInfo info, StreamingContext context) : base(info, context)
{
}
}
有关ProtoObject：
For ProtoObject:
[ProtoContract]
[ProtoInclude(1, typeof(ProtoObject<string>))]
[ProtoInclude(2, typeof(ProtoObject<int>))]
[ProtoInclude(3, typeof(ProtoObject<List<string>>))]
[ProtoInclude(4, typeof(ProtoObject<Dictionary<string, string>>))]
[ProtoInclude(5, typeof(ProtoObject<List<TrafficEntry>>))]
[ProtoInclude(6, typeof(ProtoObject<Dictionary<string, int>>))]
[ProtoInclude(7, typeof(ProtoObject<bool>))]
[ProtoInclude(8, typeof(ProtoObject<double>))]
[ProtoInclude(9, typeof(ProtoObject<decimal>))]
[ProtoInclude(10, typeof(ProtoObject<float>))]
[ProtoInclude(11, typeof(ProtoObject<long>))]
[ProtoInclude(12, typeof(ProtoObject<SerializableException>))]
[ProtoInclude(13, typeof(ProtoObject<List<UrlStatus>>))]
[Serializable]
public abstract class ProtoObject
{
public static ProtoObject<T> Create<T>(T value)
{
return new ProtoObject<T>(value);
}
public object Value
{
get { return ValueImpl; }
set { ValueImpl = value; }
}
protected abstract object ValueImpl { get; set; }
protected ProtoObject()
{
}
}
[ProtoContract]
[Serializable]
public sealed class ProtoObject<T> : ProtoObject
{
public ProtoObject()
{
}
public ProtoObject(T value)
{
Value = value;
}
[ProtoMember(1)]
public new T Value { get; set; }
protected override object ValueImpl
{
get { return Value; }
set { Value = (T)value; }
}
public override string ToString()
{
return Value.ToString();
}
}
现在的问题是，当我尝试反序列化ProtoDictionary从SQL使用下面的代码：
The problem is, when I attempt to deserialize a ProtoDictionary from SQL using the following code:
public T Deserialize<T>(IDataReader reader, string columnName)
{
MemoryStream stream = new MemoryStream();
byte[] buffer = new byte[256];
long startIndex = 0;
long bytesRead = reader.GetBytes(reader.GetOrdinal(columnName), startIndex, buffer, 0, buffer.Length);
while(bytesRead == buffer.Length)
{
stream.Write(buffer, 0, (int)bytesRead);
startIndex += bytesRead;
bytesRead = reader.GetBytes(reader.GetOrdinal(columnName), startIndex, buffer, 0, buffer.Length);
}
stream.Write(buffer, 0, (int)bytesRead);
stream.Seek(0, SeekOrigin.Begin);
return (T)Utilities.Deserialize<T>(stream);
}
我得到的错误出现InvalidOperationException：无法创建抽象类的实例。
I get the error "InvalidOperationException: Instances of abstract classes cannot be created."
我的堆栈跟踪如下：
at ctorWrapper()
at ProtoBuf.ObjectFactory`1.Create() in c:\protobuf-net_fixed\trunk\protobuf-net\ObjectFactory.cs:line 82
at ProtoBuf.Serializer`1.Deserialize[TCreation](T& instance, SerializationContext context) in c:\protobuf-net_fixed\trunk\protobuf-net\SerializerT.cs:line 568
at ProtoBuf.Property.PropertyMessageString`4.DeserializeImpl(TSource source, SerializationContext context) in c:\protobuf-net_fixed\trunk\protobuf-net\Property\PropertyMessageString.cs:line 53
at ProtoBuf.Property.PropertyPairString`3.DeserializeImpl(TSource source, SerializationContext context) in c:\protobuf-net_fixed\trunk\protobuf-net\Property\PropertyPairString.cs:line 53
at ProtoBuf.Property.PropertyList`3.DeserializeImpl(TSource source, SerializationContext context, Boolean canSetValue) in c:\protobuf-net_fixed\trunk\protobuf-net\Property\PropertyList.cs:line 64
at ProtoBuf.Property.PropertyList`3.Deserialize(TSource source, SerializationContext context) in c:\protobuf-net_fixed\trunk\protobuf-net\Property\PropertyList.cs:line 52
at ProtoBuf.Serializer`1.Deserialize[TCreation](T& instance, SerializationContext context) in c:\protobuf-net_fixed\trunk\protobuf-net\SerializerT.cs:line 568
at ProtoBuf.Serializer`1.DeserializeChecked[TCreation](T& instance, SerializationContext source) in c:\protobuf-net_fixed\trunk\protobuf-net\SerializerT.cs:line 400
at ProtoBuf.SerializerSimpleProxy`1.Deserialize(TValue& value, SerializationContext source) in c:\protobuf-net_fixed\trunk\protobuf-net\SerializerProxy.cs:line 100
at ProtoBuf.Serializer.Deserialize[T](SerializationContext source) in c:\protobuf-net_fixed\trunk\protobuf-net\Serializer.cs:line 302
at ProtoBuf.Serializer.Deserialize[T](Stream source) in c:\protobuf-net_fixed\trunk\protobuf-net\Serializer.cs:line 289
at Demand.TestFramework.Core.Utilities.Deserialize[T](MemoryStream stream) in C:\QA\trunk\TestFramework\Core\Utilities.cs:line 312
at Demand.TestFramework.Core.Reports.CrawlerReport.Deserialize[T](IDataReader reader, String columnName) in C:\QA\trunk\TestFramework\Core\Reports\CrawlerReport.cs:line 145
at Demand.TestFramework.Core.Reports.CrawlerReport.FormatSuite(Int32 parentSuiteId, Guid runId) in C:\QA\trunk\TestFramework\Core\Reports\CrawlerReport.cs:line 70
at Demand.TestFramework.Core.Reports.CrawlerReport.Format(Guid runId) in C:\QA\trunk\TestFramework\Core\Reports\CrawlerReport.cs:line 150
at ServiceLauncher.Form1.btnStart_Click(Object sender, EventArgs e) in C:\QA\trunk\TestFramework\ServiceLauncher\Form1.cs:line 24
at System.Windows.Forms.Control.OnClick(EventArgs e)
at System.Windows.Forms.Button.OnClick(EventArgs e)
at System.Windows.Forms.Button.OnMouseUp(MouseEventArgs mevent)
at System.Windows.Forms.Control.WmMouseUp(Message& m, MouseButtons button, Int32 clicks)
at System.Windows.Forms.Control.WndProc(Message& m)
at System.Windows.Forms.ButtonBase.WndProc(Message& m)
at System.Windows.Forms.Button.WndProc(Message& m)
at System.Windows.Forms.Control.ControlNativeWindow.OnMessage(Message& m)
at System.Windows.Forms.Control.ControlNativeWindow.WndProc(Message& m)
at System.Windows.Forms.NativeWindow.DebuggableCallback(IntPtr hWnd, Int32 msg, IntPtr wparam, IntPtr lparam)
at System.Windows.Forms.UnsafeNativeMethods.DispatchMessageW(MSG& msg)
at System.Windows.Forms.Application.ComponentManager.System.Windows.Forms.UnsafeNativeMethods.IMsoComponentManager.FPushMessageLoop(IntPtr dwComponentID, Int32 reason, Int32 pvLoopData)
at System.Windows.Forms.Application.ThreadContext.RunMessageLoopInner(Int32 reason, ApplicationContext context)
at System.Windows.Forms.Application.ThreadContext.RunMessageLoop(Int32 reason, ApplicationContext context)
at System.Windows.Forms.Application.Run(Form mainForm)
at ServiceLauncher.Program.Main() in C:\QA\trunk\TestFramework\ServiceLauncher\Program.cs:line 16
at System.AppDomain._nExecuteAssembly(RuntimeAssembly assembly, String[] args)
at System.AppDomain.ExecuteAssembly(String assemblyFile, Evidence assemblySecurity, String[] args)
at Microsoft.VisualStudio.HostingProcess.HostProc.RunUsersAssembly()
at System.Threading.ThreadHelper.ThreadStart_Context(Object state)
at System.Threading.ExecutionContext.Run(ExecutionContext executionContext, ContextCallback callback, Object state, Boolean ignoreSyncCtx)
at System.Threading.ExecutionContext.Run(ExecutionContext executionContext, ContextCallback callback, Object state)
at System.Threading.ThreadHelper.ThreadStart()
我不知道我做错了。任何帮助将不胜感激。
I'm not sure what I'm doing wrong. Any help would be GREATLY appreciated.
谢谢，
丹
推荐答案
这可以是简单地在V1的限制。我加入这个作为V2的测试，并通过了（我不得不发明 UrlStatus 和 TrafficEntry 来得到它来编译）：
This may be simply a limitation in "v1". I've added this as a test on "v2", and it passed (I had to invent UrlStatus and TrafficEntry to get it to compile):
public enum UrlStatus { A,B }
public enum TrafficEntry { A }
[ProtoContract]
public class SerializableException { }
[Test]
public void TestBasicRoundTrip()
{
var item = new ProtoDictionary<string>();
item.Add("abc", "def");
item.Add("ghi", new List<UrlStatus> {UrlStatus.A, UrlStatus.B});
var clone = Serializer.DeepClone(item);
Assert.AreEqual(2, clone.Keys.Count);
object o = clone["abc"];
Assert.AreEqual("def", clone["abc"].Value);
var list = (IList<UrlStatus>)clone["ghi"].Value;
Assert.AreEqual(2, list.Count);
Assert.AreEqual(UrlStatus.A, list[0]);
Assert.AreEqual(UrlStatus.B, list[1]);
}
通过V1，也许根本就没有让摘要？ （解决方法，而不是修复）
With "v1", maybe simply don't make it abstract? (workaround, not fix)
也;应该没有必要在的SerializationInfo 构造函数;未使用protobuf网（尽管你可以实施在的BinaryFormatter protobuf网提供此方法，并调用到合并）
Also; there should be no need for the SerializationInfo ctor; that is not used by protobuf-net (although you can implement protobuf-net inside BinaryFormatter by providing this method and calling into Merge)
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