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mugheessiddiqui's avatar
mugheessiddiqui
Contributor
8 years ago
Solved

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);
mugheessiddiqui's avatar
mugheessiddiqui
Contributor

Thanks Now I have gotten Blob object.

 

Second Issue is to Cast the Blob object in some list/dictionary type object of JavaScript for traversing. As I told you we have stored blob object type of System.Collection.Generic.List of Double.

 

I have found the following description of System.Collection.Generic.List that takes the "<CLRType> collection" object. I don't know how to define <CLRType> collection object.

 

Description: System.Collection.Generic.List`1 zctor_3(<CLRType> collection);

 

So far code looks like and I get type Mismatch error.

 

rs.MoveFirst();

var blobSize = rs.Fields("slices").ActualSize;
var blob = rs.Fields("slices").GetChunk(blobSize);


var objList = Aliases.appName.AppDomain("appUI.exe").dotNET.System_Collections_Generic.List_1.zctor_3(blob); // Gives "Type Mismatch Error"

 

 

AlexKaras's avatar
AlexKaras
Champion Level 3
8 years ago

Hi,

 

I am not absolutely sure, but I think that you should:

-- Register relevant (system.dll?) .Net assembly in dotNet Bridge in TestComplete and

-- Use something like

var objList = dotNET.System_Collections_Generic.List_1.zctor_3(blob);

in your code.

As a result, objList variable should contain deserialized list of doubles that cannot be used 'as is' in your test code and must be converted to array or delimited string or something like that that can be iterated and used in JScript.

 

  • mugheessiddiqui's avatar
    mugheessiddiqui
    Contributor
    8 years ago

    System.Collection.Generic.List included in mscorlib.dll and it is already available in Test Complete.

    I think I have to deserialize the object but not sure how to do it.

    • AlexKaras's avatar
      AlexKaras
      Champion Level 3
      8 years ago

      Hi,

       

      As it was suggested by HKosova, you should figure-out what is returned from Blob - this may be some string/base64 encoded string/xml/etc. Then you should find corresponding List constructor and use it to deserialize the returning value.

      However, as it was also suggested by Helen, it may be easier/more convenient to create a simple .Net assembly with one function that will receive Blob ID and database connection string as input parameters, get Blob from the database, deserialize it and return the list as, say, CrLf-delimited string. I believe that you can easily get the above code from your developers.