I am looking for example code that provides a unit test to serialize and deserialize an object from a memory stream. I have found examples using C# 2.0, however my current project uses VB.NET 1.1 (don't ask me why...), so the solution can not use generics. I am also using the NUnit framework for the unit tests.
Thanks!
This is the pattern I've settled upon:
<Test()> _
Public Sub SerializationTest()
Dim obj As New MySerializableObject()
'Perform additional construction as necessary
Dim obj2 As MySerializableObject
Dim formatter As New BinaryFormatter
Dim memoryStream As New MemoryStream()
'Run through serialization process
formatter.Serialize(memoryStream, obj)
memoryStream.Seek(0, SeekOrigin.Begin)
obj2 = DirectCast(formatter.Deserialize(memoryStream), MySerializableObject)
'Test for equality using Assert methods
Assert.AreEqual(obj.Property1, obj.Property1)
'etc...
End Sub
NUnit has built in support for this which makes it quite a bit easier:
Dim obj As New MySerializableObject()
Assert.That(obj, Is.BinarySerializable)
Or for xml:
Dim obj As New MySerializableObject()
Assert.That(obj, Is.XmlSerializable)
If all you want to do is to ensure that they are serializable then all you should have to do it to do a serialization of an object and make sure no XmlSerializationException was thrown
[Test]
public void ClassIsXmlSerializable()
{
bool exceptionWasThrown = false;
try
{
// .. serialize object
}
catch(XmlSerializationException ex)
{
exceptionWasThrown = true;
}
Asset.IsFalse(exceptionWasThrown, "An XmlSerializationException was thrown. The type xx is not xml serializable!");
}
Hmm...so you are trying to write a unit test for serialization? Or for streams? This is hopefully done by MS already...but if you don't trust or implement something on your own...you could just fill object with some data, save it, restore it, and check if the fields values are in place?
Related
I would like to deserialize the returned JSON from a service call in VB.NET to an anonymous type but I was having error. It works in C# using dynamic type but i dont know how to do it in VB.
Here is my JSON returned from a web service call:
{"format":"png","height":564,"width":864}
Here is my VB code json above assigned to param text:
Dim testObj = Newtonsoft.Json.JsonConvert.DeserializeObject(text)
But when i tried to access testObj.format, an exception was thrown with message
{"Public member 'format' on type 'JObject' not found."}
I already have added Option Strict Off. I dont want to use an Object/Class to deserialize the JSON. If its in C# assigning this to dynamic type will be working fine.
Can anyone please help? I am not expert in VB but I need to have this running on VB. TIA
Dim js As New System.Web.Script.Serialization.JavaScriptSerializer
Dim testObj = js.Deserialize(source, New Object().GetType())
Then you can access the key(attribute name)/values via:
value=testobj(key)
One more thing, you can access your Newtonsoft key(attribute name)/values through:
value=testObj.item(key)
Dim js As New System.Web.Script.Serialization.JavaScriptSerializer
Dim DeSerialObjEventData = New With {.Prop1 = String.Empty, .Prop2 = String.Empty, .Prop3 = String.Empty}...
Dim testObj = js.DeserializeAnnonomusType(source, DeSerialObjEventData)
I am producing an XML file in my unit test using
Public Sub rssParserTest
Dim Const rssUri as String = "rssTestFile.xml"
Dim xmlFile = <rss version="2.0">
...
</rss>
xmlFile.save(rssUri)
rssParser(rssUri)
End Sub
and consuming the uri with an XMLTextReader
Public Sub rssParser(ByVal rssUri as string)
Dim rssXml = New XmlTextReader(rssUri)
rssXml.read
...
End Sub
I want to remove the unit test dependency on a physical file and use a stream instead but my efforts so far have come to nought. (Is this best practise?)
I am using NMock2 for mocking if I should be doing something with that.
Rather than force an XmlTextReader via a stream, if you just nead an XmlReader you can just use XNode.CreateReader. That's a much simpler approach than saving to a stream, unless your API forces you to use a stream or an XmlTextReader.
xmlFile is an XDocument, which can be saved into a MemoryStream, see the following SO question for details:
Convert XDocument to Stream (The code samples are in C#, but the .NET API methods used are the same.)
You can then make your method accept a generic Stream, which can then be a MemoryStream (in the unit test) or a FileStream.
Which is the most performant way to read a large csv file in .NET?
Using FileStream? or another class?
Thanks!
You can use the StreamReader returned by FileInfo.OpenText:
Dim file As New FileInfo("path\to\file")
Using reader As StreamReader = file.OpenText()
While Not reader.EndOfStream
Dim nextLine As String = reader.ReadLine()
ProcessCsvLine(nextLine)
End While
End Using
If you want to read it all into memory, a simple File.ReadAllText() will do just fine.
EDIT: If your file is indeed very large, then you can use the StreamReader class, see here for details. This approach is sometimes inevitable but should mostly be avoided for style reasons. See here for a more in-depth discussion.
The most efficient way of doing this is by taking advantage of deffered execution in LINQ. You can create a simple Linq-To-Text function that read one line at a time, work on it and then continue. This is really helpful since the file is really large.
I would desist from using the ReadBlock or ReadBlock or ReadToEnd methods of StreamReader class since they tend to read a number of lines at once or even the entire lines in the file. This ends up consuming more memory than if a line was read one at a time.
public static IEnumerable<string> Lines(this StreamReader source)
{
String line;
if (source == null)
throw new ArgumentNullException("source");
while ((line = source.ReadLine()) != null)
{
yield return line;
}
}
Note that the function is an extension method of the StreamReader class. This means it can be used as follows:
class Program
{
static void Main(string[] args)
{
using(StreamReader streamReader = new StreamReader("TextFile.txt"))
{
var tokens = from line in streamReader.Lines()
let items = line.Split(',')
select String.Format("{0}{1}{2}",
items[1].PadRight(16),
items[2].PadRight(16),
items[3].PadRight(16));
}
}
}
I had very good experience with this library:
http://www.codeproject.com/KB/database/CsvReader.aspx
I am using this library for Csv reading. This is really nice to use
http://www.codeproject.com/Articles/11698/A-Portable-and-Efficient-Generic-Parser-for-Flat-F
I wonder if anyone can help me - I've not done much with reflection but understand the basic principles.
What I'm trying to do:
I'm in the process of developing a class that gathers a lot of information about the local system, network, etc... to be used for automated bug reporting. Instead of having to change my test harness every time I add a new property, I'd (ideally) like to be able to serialise the lot as an XML string and just display that in a textbox.
Unfortunately, the Framework won't use the default XML serializer on read-only properties (which almost all of mine are) as they wouldn't deserialize properly
[Not sure I agree with the assumption that anything serialized must be de-serializable - MS says this is a feature "by design" which I suppose I can understand - Perhaps a tag to indicate that it should be serialized anyway would be advantageous?]
The initial approach was to make properties gettable and settable (with a throw exception on the setter) but the amount of work tidying this up afterwards seems a little excessive and I would want the properties to be read-only in the final version.
What I need help with:
My current plan is to use reflection to recursively iterate through each (public) property of my topmost gathering class. The problem is, the samples I've seen don't handle things recursively. Additionally, I only want to inspect an object's properties if it's in one of my assemblies - Otherwise just call .ToString on it.
If I don't have the inspection limited to my assembly, I assume I'll get (say) a string which then contains a Length which in turn will have .Tostring method...
For the purposes of this project, I can almost guarantee no circular references within my code and as this will only be used as a development tool so I'm not too concerned about it running amok now and then.
I'd appreciate some examples/advice.
Many thanks in advance.
This will hopefully get you started. It prints a tree directly to the console so you'll need to adjust to output XML. Then change the IsMyOwnType method to filter out the assemblies you're interested in, right now it only cares about types in the same assembly as itself.
Shared Sub RecurseProperties(o As Object, level As Integer)
For Each pi As PropertyInfo In o.GetType().GetProperties()
If pi.GetIndexParameters().Length > 0 Then Continue For
Console.Write(New String(" "c, 2 * level))
Console.Write(pi.Name)
Console.Write(" = ")
Dim propValue As Object = pi.GetValue(o, Nothing)
If propValue Is Nothing Then
Console.WriteLine("<null>")
Else
If IsMyOwnType(pi.PropertyType) Then
Console.WriteLine("<object>")
RecurseProperties(propValue, level+1)
Else
Console.WriteLine(propValue.ToString())
End If
End If
Next
End Sub
Shared Function IsMyOwnType(t As Type) As Boolean
Return t.Assembly Is Assembly.GetExecutingAssembly()
End Function
you extension version on c# to use on any object
using System;
using System.Collections.Generic;
using System.Linq;
using System.Text;
using System.Reflection;
namespace Extensions
{
public static class ObjectExtension
{
public static string ToStringProperties(this object o)
{
return o.ToStringProperties(0);
}
public static string ToStringProperties(this object o, int level)
{
StringBuilder sb = new StringBuilder();
string spacer = new String(' ', 2 * level);
if (level == 0) sb.Append(o.ToString());
sb.Append(spacer);
sb.Append("{\r\n");
foreach (PropertyInfo pi in o.GetType().GetProperties())
{
if (pi.GetIndexParameters().Length == 0)
{
sb.Append(spacer);
sb.Append(" ");
sb.Append(pi.Name);
sb.Append(" = ");
object propValue = pi.GetValue(o, null);
if (propValue == null)
{
sb.Append(" <null>");
} else {
if (IsMyOwnType(pi.PropertyType))
{
sb.Append("\r\n");
sb.Append(((object)propValue).ToStringProperties(level + 1));
} else{
sb.Append(propValue.ToString());
}
}
sb.Append("\r\n");
}
}
sb.Append(spacer);
sb.Append("}\r\n");
return sb.ToString();
}
private static bool IsMyOwnType(Type t)
{
return (t.Assembly == Assembly.GetExecutingAssembly());
}
}
}
I have to return a lot of values back to my windows application from my webService. But how would I return more than just a single string/int/boolean from my WebService to my Application. How would I return a collection, keyValuePair, or even better, a DataSet? Or is this just imposible?
thank you :)
any serializable class can be returned from a web service
If your webservice is written in ASP.NET it's as simple as setting the return type from your webservice to be the more complex type. Most serializable types are supported.
The best method I've used with webservices is to return XML as a string. This way there are no compatability issues and parsing the XML is easy enough.
Along the same lines as returning XML, if you're returning to javascript code, you may want to consider returning your complex type as serialized in JSON.
Here is an extension method which makes this really easy...
<Extension()> Public Function ToJSON(Of T As Class)(ByVal target As T) As String
Dim serializer = New System.Runtime.Serialization.Json.DataContractJsonSerializer(GetType(T))
Using ms As MemoryStream = New MemoryStream()
serializer.WriteObject(ms, target)
ms.Flush()
Dim bytes As Byte() = ms.GetBuffer()
Dim json As String = Encoding.UTF8.GetString(bytes, 0, bytes.Length).Trim(Chr(0))
Return json
End Using
End Function
Then in your data service, you can simply call
Return MyObject.ToJSON