How to implement a generic method(pattern)?

Hi,

I have the following method

public void ReadXmlFromFile(string path, string fileName)
{
string filePath = Path.Combine(path, fileName);

XmlSerializer deserializer = new XmlSerializer(TipsProvider.TipsList.GetType());
TextReader textReader = null;

            try
            {
               textReader = new StreamReader(filePath);
               TipsProvider.TipsList = (List)deserializer.Deserialize(textReader);
            }
            catch(Exception e)
            { }
            finally
            {
               if (textReader != null)
                    textReader.Close();
            }
        }

But now I want to use this method to also read xml from anothe typeof object.
The 3 bold lines is the objects that is "hard coded" in this method and should be generic.

How do i implement this?
Should i implement some kind of pattern?

Br Morten

The first thing that strikes me with that method is that you're accessing an external field TipsProvider.TipsList which appears to be of type List.

If you want to genericize this method, then you'll need to make it self-contained by passing TipsProvider.TipsList as a ref parameter.

So, if the type parameter will always be a List of some type, then you could do:

public void ReadXmlFromFile(string path, string fileName, ref List list)

{

string filePath = Path.Combine(path, fileName);

XmlSerializer deserializer = new XmlSerializer(typeof(List));

TextReader textReader = null;

try

{

textReader = new StreamReader(filePath);

list = (List)deserializer.Deserialize(textReader);

}

catch(Exception e)

{ }

finally

{

if (textReader != null)

textReader.Close();

}

or, if it could be any arbitrary type, you could do:

public void ReadXmlFromFile(string path, string fileName, ref T obj)

{

string filePath = Path.Combine(path, fileName);

XmlSerializer deserializer = new XmlSerializer(typeof(T));

TextReader textReader = null;

try

{

textReader = new StreamReader(filePath);

obj = (T)deserializer.Deserialize(textReader);

}

catch(Exception e)

{ }

finally

{

if (textReader != null)

textReader.Close();

}

In either case, you'd call it with:

ReadXmlFromFile(path, fileName, ref TipsProvider.TipsList);

The compiler would infer 'T' from that.

1 Reply

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Vulpes13y ago
Accepted answer
The first thing that strikes me with that method is that you're accessing an external field TipsProvider.TipsList which appears to be of type List.

If you want to genericize this method, then you'll need to make it self-contained by passing TipsProvider.TipsList as a ref parameter.

So, if the type parameter will always be a List of some type, then you could do:

public void ReadXmlFromFile(string path, string fileName, ref List list)
{
string filePath = Path.Combine(path, fileName);

XmlSerializer deserializer = new XmlSerializer(typeof(List));
TextReader textReader = null;

try
{
textReader = new StreamReader(filePath);
list = (List)deserializer.Deserialize(textReader);
}
catch(Exception e)
{ }
finally
{
if (textReader != null)
textReader.Close();
}
}

or, if it could be any arbitrary type, you could do:

public void ReadXmlFromFile(string path, string fileName, ref T obj)
{
string filePath = Path.Combine(path, fileName);

XmlSerializer deserializer = new XmlSerializer(typeof(T));
TextReader textReader = null;

try
{
textReader = new StreamReader(filePath);
obj = (T)deserializer.Deserialize(textReader);
}
catch(Exception e)
{ }
finally
{
if (textReader != null)
textReader.Close();
}
}

In either case, you'd call it with:

ReadXmlFromFile(path, fileName, ref TipsProvider.TipsList);

The compiler would infer 'T' from that.