如何從Dictionary.Where（）在vb.net

Question

第一次嘗試倉庫模式投字典，但卡住如何返回字典出的Dictionary.Where（條款）

Public Function GetWhere(ByVal clause As System.Func(Of myObject, Boolean)) As IRepositoryRead(Of String, myObject) Implements IRepositoryRead(Of String, myObject).GetWhere 
    Return _myDict.Values.Where(clause).ToDictionary(??) 
End Function 

Public Shared Function Filter_OnlyPublic(ByVal SomeMyObject, As myObject) As Boolean 
    Return SomeMyObject.isPublic 
End Function 

_myDict.Values.Where（子句）工作正常。但是如何將結果（內存中查詢）作爲字典返回？

Answer 1

Return _myDict.Values.Where(clause).ToDictionary(Function (x) x.key) 

{x.key}中的鍵將是myObject中變量的名稱，您希望成爲詞典的鍵。

Answer 2

您可以使用類似下面的內容來過濾字典。

Dim dic As New Dictionary(Of String, String) 'Creating new Dictionary object 
dic.Add("Stackoverflow", "somevalue1") 'Adding some items 
dic.Add("Youssef1", "somevalue2") 
dic.Add("Stackoverflow2", "somevalue3") 
dic.Add("Youssef2", "somevalue4") 
Dim newDic = dic.Where(Function(pair) pair.Key.Contains("Stackoverflow")).ToDictionary(Function(pair) pair.Key, Function(pair) pair.Value) 'Filtering the dictionary and assigning it to newDic 
For i = 0 To newDic.Count - 1 'Loop through newDic 
    MessageBox.Show("Key: " & newDic.Keys(i) & Environment.NewLine & "Value: " & newDic.Values(i)) 'Shows the filtered dictionary (newDic) keys & values 
Next