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
)

var data = new LurchTableTest<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 var = New LurchTableTest(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))