Public Overloads Function TryAdd( _
   ByVal key As TKey, _
   ByVal value As TValue _
) As Boolean

public bool TryAdd( 
   TKey key,
   TValue value
)

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))