LINQ - 向datacontext添加函数

Question

I have a linq table "KUND" who is read only to me. It has some special characters in it to which i have writter a function to switch them out to the ones i want.

public static string changeSpecialCharacters(string kund)
    {
        StringBuilder b = new StringBuilder(kund);

        b = b.Replace("Õ", "å");
        b = b.Replace("┼", "Å");
        b = b.Replace("õ", "ä");
        b = b.Replace("─", "Ä");
        b = b.Replace("÷", "ö");
        b = b.Replace("Í", "Ö");
        b = b.Replace("'", " ");
        b = b.Replace("¦", "´");
        b = b.Replace("Ï", "Ø");

        return b.ToString();
    }

I now have two questions:

1 Can i add this function to the GET in the autogenerated datacontext so i dont have to call it all over my code? Ive added it but it seems to be deleted whenever i change how my datacontext is (add/remove table). 2 Any suggestions how to make that function better in regards to speed perhaps?

Answer 1

Never edit the .designer.cs; instead, add a second file, and use partial class to add the method, for example:

namespace Your.Namespace
{
    partial class YourDataContext
    {
        // your methods here
    }
}

No; you can't add this to the get. Another alternative, though, is an extension method:

namespace Some.Utility.Namespace
{
    public static class SomeUtilityClass
    {
        public static string ChangeSpecialCharacters(this string kund)
        { ... } // note the "this" in the above line
    }
}

Now you can use:

string name = obj.Name.ChangeSpecialCharacters();

personally I would rename this to clarify the direction of the change, and have two methods - one to encode, one to decode.

---

Re doing this for a set of data; perhaps:

public static IEnumerable<SomeType> ChangeSpecialCharacters(
    this IEnumerable<SomeType> items)
{
    foreach(var item in items)
    {
        item.Name = item.Name.ChangeSpecialCharacters();
        item.Foo = item.Foo.ChangeSpecialCharacters();
        ...
        item.Bar = item.Bar.ChangeSpecialCharacters();
        yield return item;
    }
}

Answer 2

probably you could initialize your variable as:

private string kund;
public string Kund
{
    get
    {
        return changeSpecialCharacters(string kund);
    }
    set
    {
        kund = value;
    }
}