Public Overloads Function TryUpdate( _
   ByVal key As TKey, _
   ByVal fnUpdate As CSharpTest.Net.Collections.KeyValueUpdate(Of TKey,TValue) _
) As Boolean

public bool TryUpdate( 
   TKey key,
   CSharpTest.Net.Collections.KeyValueUpdate<TKey,TValue> fnUpdate
)

SynchronizedDictionary<int, string> data =
    new SynchronizedDictionary<int, string>(new Dictionary<int, string>());

Assert.IsTrue(data.TryAdd(1, "a"));
Assert.IsFalse(data.TryAdd(1, "a"));

Assert.IsTrue(data.TryUpdate(1, "a"));
Assert.IsTrue(data.TryUpdate(1, "c"));
Assert.IsTrue(data.TryUpdate(1, "d", "c"));
Assert.IsFalse(data.TryUpdate(1, "f", "c"));
Assert.AreEqual("d", data[1]);
Assert.IsTrue(data.TryUpdate(1, "a", data[1]));
Assert.AreEqual("a", data[1]);
Assert.IsFalse(data.TryUpdate(2, "b"));

string val;
Assert.IsTrue(data.TryRemove(1, out val) && val == "a");
Assert.IsFalse(data.TryRemove(2, out val));
Assert.AreNotEqual(val, "a");

Assert.IsFalse(data.TryUpdate(1, (k, x) => x.ToUpper()));
data[1] = "a";
data[1] = "b";
Assert.IsTrue(data.TryUpdate(1, (k, x) => x.ToUpper()));
Assert.AreEqual("B", data[1]);

Dim data As New SynchronizedDictionary(Of Integer, String)(New Dictionary(Of Integer, String)())

Assert.IsTrue(data.TryAdd(1, "a"))
Assert.IsFalse(data.TryAdd(1, "a"))

Assert.IsTrue(data.TryUpdate(1, "a"))
Assert.IsTrue(data.TryUpdate(1, "c"))
Assert.IsTrue(data.TryUpdate(1, "d", "c"))
Assert.IsFalse(data.TryUpdate(1, "f", "c"))
Assert.AreEqual("d", data(1))
Assert.IsTrue(data.TryUpdate(1, "a", data(1)))
Assert.AreEqual("a", data(1))
Assert.IsFalse(data.TryUpdate(2, "b"))

Dim val As String
Assert.IsTrue(data.TryRemove(1, val) AndAlso val = "a")
Assert.IsFalse(data.TryRemove(2, val))
Assert.AreNotEqual(val, "a")

Assert.IsFalse(data.TryUpdate(1, Function(k, x) x.ToUpper()))
data(1) = "a"
data(1) = "b"
Assert.IsTrue(data.TryUpdate(1, Function(k, x) x.ToUpper()))
Assert.AreEqual("B", data(1))