CollectionBase InnerList with Arrays

[adriaandavel]

Hi all,

I am trying to use a collection of String Arrays in an inherited
instance of CollectionBase, but the InnerList.IndexOf does not seem to
work, any ideas?

My code is:

public void Add(string str1, string str2, string str3)
{
string[] Detail = new string[3] { str1, str2, str3};
this.InnerList.Add(Detail);
}

public int ArrayPosition(string str1, string str2, string str3)
{
string[] Detail = new string[3] { str1, str2, str3};
return InnerList.IndexOf(Detail);
}

The Add() works fine, and in the debugger I can see all the Arrays I've
added, but the ArrayPosition() always returns -1...

 

[Marc Gravell]

That is because you are creating a new array, and the list is likely using
referential comparison on the array reference. You would need to use a
comparer that looked inside the array.

This is essentially ths same as the following, which prints "false" 3
times - because the arrays just are not connsidered "equal" by default:

string[] a = { "a", "b", "c" };
string[] b = { "a", "b", "c" };
Console.WriteLine(a == b);
Console.WriteLine(a.Equals(b));
Console.WriteLine(Array.Equals(a,b));

Marc

 

[Dustin Campbell]

I am trying to use a collection of String Arrays in an inherited

instance of CollectionBase, but the InnerList.IndexOf does not seem to
work, any ideas?

My code is:

public void Add(string str1, string str2, string str3)
{
string[] Detail = new string[3] { str1, str2, str3};
this.InnerList.Add(Detail);
}
public int ArrayPosition(string str1, string str2, string str3)
{
string[] Detail = new string[3] { str1, str2, str3};
return InnerList.IndexOf(Detail);
}
The Add() works fine, and in the debugger I can see all the Arrays
I've added, but the ArrayPosition() always returns -1...

BTW (this is a little OT), you should use the "List" property instead of
"InnerList" inside of a CollectionBase descendent. If you don't use List,
known of the protected methods that you can override will be called (e.g.
OnInsert, OnRemove, OnValidate).

Best Regards,
Dustin Campbell
Developer Express Inc.