Forum Discussion

mugheessiddiqui's avatar
mugheessiddiqui
Contributor
8 years ago

Read Blob object from DB and convert to System.Collection.Generic.List type of object.

I have scenario where database field stores a System.Collection.Generic.List of Double object. Now I want to read a BLOB object from database field and convert it to list of Array or any type collect...
  • tristaanogre's avatar
    tristaanogre
    8 years ago

    Rather than "Value", you might want to use the GetChunk method.  What you'll need to do is get the ActualSize of the field and then use GetChunk to retrieve it.  I've not tested this but it might look something like this:

     rs.MoveFirst();
var blobSize = rs.Fields("slices").ActualSize;
  var blob = rs.Fields("slices").GetChunk(blobSize);
HKosova's avatar
HKosova
SmartBear Alumni (Retired)
8 years ago

Can you ask the developers what code they are using to serialize the list into the DB? This should give you the best idea of how to do the opposite.

 

Maybe you need to use BinaryFormatter.Deserialize as shown here:
http://stackoverflow.com/questions/2949666/deserialize-stream-to-listt-or-any-other-type
http://stackoverflow.com/questions/26383711/serialize-deserialize-a-list-of-objects-using-binaryformatter
http://stackoverflow.com/questions/18876229/serializing-and-deserializing-a-listlistobject-with-binaryformatter
http://stackoverflow.com/questions/33724860/deserialize-list-of-objects-from-a-file-to-be-displayed

 

Maybe you need to read the DB using .NET classes and not ADO, so that the blob data type is compatible with .NET.

 

I'd suggest writing the deserialization code in C#/VB.NET in Visual Studio first. Once you have the code that works, you can port it to TestComplete, or you can compile the .NET code into an assembly/class library and call it from TestComplete via dotNET.