SqlDataReader在vb.net 2008中導致SqlException

我遇到的問題是我不斷捕獲SQL異常。它發生在我的'FlexList'類中，我運行了調試器，它是一行代碼「Dim mySqlDataReader As SqlDataReader = myCommand.ExecuteReader」，它正在破壞它並拋出錯誤，我做錯了什麼？提供的幫助將是非常有益的SqlDataReader在vb.net 2008中導致SqlException

查詢語句進入該類遇到錯誤：

Public Class MainView 
    Private _thatList As New GetClass 
    Private _AddEditTerms As New Add_EditWindow 
    Private _listManager As New listManager 
    Private myQuery As String = _thatList.getAvaliableStatuses 
    Private _flexList As New FlexList(myQuery) 
'cut out the rest of the code 
End Class

類遇到錯誤：進口System.Data.SqlClient的進口System.Collections.Specialized

Public Class FlexList 
    Public ReadOnly rows As New List(Of Dictionary(Of String, String)) 
    Public ReadOnly fields() As String 

    Public Sub New(ByRef myQuery As String) 
    Dim myConnection As SqlConnection = DataConnection.getProperityDBConnection() 
    Dim row As Dictionary(Of String, String) 

    Try 
     myConnection.Open() 
     Dim myCommand As New SqlCommand() 
     myCommand.Connection = myConnection 
     myCommand.CommandText = myQuery 
     Dim mySqlDataReader As SqlDataReader = myCommand.ExecuteReader 

     If mySqlDataReader.HasRows Then 
      Dim fieldCount = mySqlDataReader.FieldCount 
      ReDim fields(fieldCount - 1) 

      mySqlDataReader.Read() 
      For i = 0 To fieldCount - 1 
       fields(i) = mySqlDataReader.GetName(i) 
      Next 

      Do 
       row = New Dictionary(Of String, String) 
       For i = 0 To fieldCount - 1 
        row.Add(mySqlDataReader.GetName(i), IIf(mySqlDataReader.IsDBNull(i), "NULL", mySqlDataReader.GetValue(i).ToString)) 
       Next 
       rows.Add(row) 
       row = Nothing 
      Loop While mySqlDataReader.Read() 

     End If 

    Catch ex As SqlException 
     MsgBox("Database Error. Please contact you system administor") 
    Catch ex As DataException 
     MsgBox("Connection Error. Please contact The Delevelopement Team") 
    Catch ex As Exception 
     MsgBox("An Unknown Error has occured. Try again and report the error if it persists: " & vbCr & ex.ToString) 
    Finally 
     myConnection.Close() 
    End Try 

End Sub 

End Class

存儲過程我使用的測試：進口System.Data.SqlClient的

Public Class Get_Avaliable_Statuses 
Public Function getAvailableStatuses() 
    Dim connection As SqlConnection = DataConnection.getProperityDBConnection 

    Dim insertCommand As New SqlCommand("dbo.ksp_Get_Available_Statuses", connection) 
    insertCommand.CommandType = CommandType.StoredProcedure 

    Try 
     connection.Open() 
     Dim count As Integer = insertCommand.ExecuteNonQuery() 
     If count > 0 Then 
      Return True 
     Else 
      Return False 
     End If 
    Catch ex As Exception 
     Throw ex 
    Finally 
     connection.Close() 
    End Try 
End Function 
End Class

來源

2014-01-16 Gnathan

...哪條線是錯誤？我看到一個可能的空引用'IIf（mySqlDataReader.IsDBNull（i），「NULL」，mySqlDataReader.GetValue（i）.ToString）'。即使它是空的，它仍然會評估錯誤的部分。改變'IIF（）'只是'If（）'會解決這個問題。 – helrich

這個問題實際上是這樣回答的：「Dim mySqlDataReader As SqlDataReader = myCommand.ExecuteReader」 – cubitouch

我不想問這個問題，但是你不覺得這個問題中包含的實際異常是非常重要的嗎？ –

還有就是你的問題 - 「[*]」用「*」。刪除方括號

來源

2014-01-16 16:45:17

SqlDataReader在vb.net 2008中導致SqlException

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