4

Based on the code found here: protobuf and List<object> - how to serialize / deserialize? I've created a generic "ProtoDictionary" that has a value type of ProtoObject.

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) 
    {

    }
}

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();
    }
}

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);
}

I get the error "InvalidOperationException: Instances of abstract classes cannot be created."

My StackTrace is as follows:

   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()

I'm not sure what I'm doing wrong. Any help would be GREATLY appreciated.

Thanks, Dan

Community
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Dan at Demand
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2 Answers2

1

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]);
    }

With "v1", maybe simply don't make it abstract? (workaround, not fix)

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)

Marc Gravell
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  • So, if I don't make ProtoObject abstract, I get this error instead "ProtoException: Unterminated group(s) in a message or sub-message". How close is v2 to being usable or how hard would it be to fix this in v1? – Dan at Demand Jul 16 '10 at 18:11
  • @Dan "Unterminated group" sounds like you didn't get the whole data, or you accidentally packed some garbage. Do you have a reproducible example I can work with? – Marc Gravell Jul 16 '10 at 21:20
  • Well...I feel like an idiot. The data that was being used for the deserialization was bad. Once that was fixed, everything worked. No need to remove the abstract declaration even. Sorry to have wasted your time! Thank you so much for the help!!!! Again, sorry for wasting your time. – Dan at Demand Jul 16 '10 at 21:43
0

Is there a reason you need to separate ProtoObject and ProtoObject<T>? protobuf-net seems to create an object of type T (in a roundabout way) in ObjectFactory, and I'm assuming that T is going to be ProtoObject, which is abstract.

Sorry I'm not more helpful - I don't have too much time to dig further right at the moment.

TheEvilPenguin
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