C# Error
CS1063 – The best overloaded Add method ‘{0}’ for the collection initializer element is obsolete. {1}
Reason for the Error & Solution
The best overloaded Add method for the collection initializer element is obsolete.
This error occurs when a type that implements IEnumerable implements one or more Add methods but the best matching overload is attributed with ObsoleteAttribute and the ObsoleteAttribute.IsError property is initialized to true.
Example
The following sample generates CS1063:
// CS1063.cs (9,38)
using System;
using System.Collections;
class Test
{
public static void Main()
{
B coll = new B { "a" };
}
}
public class B : IEnumerable
{
[Obsolete("Don't use this overload", true)]
public void Add(string s)
{
//...
}
public void Add(int i)
{
//...
}
IEnumerator IEnumerable.GetEnumerator()
{
return null;
}
}
To correct this error
If you own the enumerable type code and want to utilize a collection initializer, remove the ObsoleteAttribute.
public class B : IEnumerable
{
public void Add(string s)
{
//...
}
public void Add(int i)
{
//...
}
IEnumerator IEnumerable.GetEnumerator()
{
return null;
}
}
If you do not own the enumerable type code, you will have to choose another means to initialize the collection.
