VB.NET和linQ：如何使用值從字典中刪除條目

Question

我有一個字典收藏如下：

mydic.addvalue(key1, val1)
mydic.addvalue(key2, val1)
mydic.addvalue(key3, val1)
mydic.addvalue(key4, val2)
mydic.addvalue(key5, val2)

從上面的字典中，我想刪除value ==“ val1”的所有條目，以便結果僅包含以下條目：

mydic.addvalue(key4, val2)
mydic.addvalue(key5, val2)

我的VB源代碼在VS2008上，目標版本為3.5

Answer 1

Sub RemoveByValue(Of TKey, TValue)(ByVal dictionary As Dictionary(Of TKey, TValue), ByVal someValue As TValue)

    Dim itemsToRemove = (From pair In dictionary _
                        Where pair.Value.Equals(someValue) _
                        Select pair.Key).ToArray()

    For Each item As TKey In itemsToRemove
        dictionary.Remove(item)
    Next

End Sub

用法：

Dim dictionary As New Dictionary(Of Int32, String)
dictionary.Add(1, "foo")
dictionary.Add(2, "foo")
dictionary.Add(3, "bar")

RemoveByValue(dictionary, "foo")