類的集合 - 數組屬性沒有正確填充

Question

我正在將vb6程序遷移到vb.net。基本上下面的函數是創建一個類的集合。我使用該鍵作爲test_id來訪問其他地方集合中的各個類。我遇到的唯一問題是該類的屬性Sieves將隨着集合中的每個類的添加而更新。換句話說 - 當我在第一個循環/第一個類上執行時 - 我將sngSieveArray分配給我的類的屬性（.sieves）。一切都很好，數據正是數據庫包含的內容。在第二個循環中 - 只要sngsievarray填充當前類的數據 - 第一類的篩數組就會更新爲相同的數據。

總共有3個類 - 所以每個.sieves屬性都被賦予最後一個類的篩選數組。

我完全喪失瞭如何出錯的問題 - 班級中的所有其他屬性都保留在每個相繼創建的類中。

Public Function GetSieveTestsInLot(mix_app_id As Long, mix_lot_id As Long, Optional,combinedMixLot As Long = 0, Optional combinedMixLot2 As Long = 0, Optional boolExclude As boolean = False) As Collection 
    On Error GoTo ErrorHandler 
    Dim strsql As String 
    Dim rsTests As SqlClient.SqlDataReader 
    Dim mycmd As SqlClient.SqlCommand 
    Dim mySieveTest As clsSieveTest 
    Dim sngSieveArray(0 To 12) As Single 

    Dim theConn As SqlClient.SqlConnection = New SqlClient.SqlConnection(My.Settings.AsphaltConnectionString) 
    If Not (theConn.State = ConnectionState.Open) Then 
     theConn.Open() 
    End If 

    strsql = "select mix_lot.MIX_LOT_ID,LOT_NUMBER, EXCLUDED,SAMPLE_TEST_ID, mix_lot.MIX_APPLICATION_ID, p.* from " _ 
     & "(select TEST_PERCENT_PASSING.PER_PASSING, TEST_PERCENT_PASSING.SIEVE_ID, TEST_PERCENT_PASSING.TEST_ID from TEST_PERCENT_PASSING) as t " _ 
     & "pivot (min(per_passing) for Sieve_id in ([1],[2],[3],[4],[5],[6],[7],[8],[9],[10],[11],[12],[13])) p inner join TEST_DATA_CALC on TEST_DATA_CALC.TEST_ID = p.TEST_ID " _ 
     & "inner join MIX_LOT on MIX_LOT.MIX_LOT_ID = TEST_DATA_CALC.MIX_LOT_ID where MIX_APPLICATION_ID = " & mix_app_id & " And (MIX_LOT.mix_lot_id = " & mix_lot_id & " or mix_lot.mix_lot_id = " & combinedMixLot _ 
    & " or mix_lot.mix_lot_id = " & combinedMixLot2 & ")" 



    mycmd = New SqlClient.SqlCommand 
    mycmd.CommandText = strsql 
    mycmd.CommandType = CommandType.Text 
    mycmd.Connection = theConn 

    rsTests = mycmd.ExecuteReader 

    GetSieveTestsInLot = New Collection 
    If rsTests.HasRows Then 
     Do While rsTests.Read 
      If Not (boolExclude = True And rsTests!excluded = True) Then 
       mySieveTest = New clsSieveTest 
       With mySieveTest 
        .test_id = rsTests!test_id 
        .mix_lot_id = rsTests!mix_lot_id 
        .lot_number = rsTests!lot_number 
        .mix_app_id = mix_app_id 
        .sample_test_id = rsTests!sample_test_id 
        .test_exlcuded = rsTests!excluded 

        For i = 0 To 12 
         For j = 0 To rsTests.FieldCount - 1 
          ' MsgBox(rsTests.GetName(j).ToString) 
          If rsTests.GetName(j).ToString = (i + 1).ToString Then 
           ' MsgBox(rsTests.Item(j).ToString) 
           sngSieveArray(i) = rsTests.Item(j) 
          End If 
         Next j 
        Next i 

        .sieves = sngSieveArray 
       End With 

       GetSieveTestsInLot.Add(mySieveTest, CStr(mySieveTest.test_id)) 
      End If 

     Loop 
     rsTests.Close() 
    End If 

    rsTests = Nothing 
    mycmd = Nothing 
    theConn.Close() 
    theConn = Nothing 
    Exit Function 

ErrorHandler: 
    MsgBox("An error has occured in GetSieveTestsInLot in clsSieveTest with Error number: " & Err.Number & " defined as" & vbCrLf _ 
    & Err.Description, vbCritical, "Program Failure") 
    rsTests = Nothing 
    mycmd = Nothing 
    theConn.Close() 
    theConn = Nothing 
End Function 

MIX_LOT_ID LOT_NUMBER排除SAMPLE_TEST_ID MIX_APPLICATION_ID爲test_id 1 2 3 4 5 6 7 8 9 10 11 12 13

---

141 1 0 1 36 430 5.15 100 100 100 90.7 76.3 49.6 35.3 24.8 17.7 13.1 8.5 5.5 141 1 0 2 36 431 5.35 100 100 100 91.2 78.5 48.6 35.4 25 18.6 13.4 8 4.9 141 1 0 3 36 432 5.16 100 100 98.8 84.8 74.1 53.8 38.4 26.8 19 13.7 9.1 5.2

（3 row（s）affected）

Answer 1

原因是因爲數組是引用類型。 clsSieveTest的每個實例的.sieves屬性都引用數組的相同實例。您需要將您的Do While循環內的內的sngSieveArray 的聲明移到內部，以便您的clsSieveTest的每個新實例都獲得它自己的數組。