Question

我有这种方法：

Private Function convertInteger(intInteger As Object) As Integer

    If IsDBNull(intInteger) Then
        convertInteger = 0
    Else
        convertInteger = cInt(intInteger)
    End If

End Function

但它会返回此错误：

operator'='未定义类型'integer'并输入'dbnull'

我试图将DBnull值转换为0 ..

但问题是我尝试转换的值并不总是DBnull ..所以我该如何处理呢？

Answer 1

试试这个

Private Function convertInteger(intInteger As Object) As Integer

    If intInteger = DBNull.Value Then
        Return 0
    End If

    Return intInteger

End Function

根据[Tim Schmelter]的建议，研究Nullable类型

Answer 2

试试这个

Private Function convertInteger(ByVal intInteger As Object) as Integer
   If IsDBNull(intInteger) Then
       Return 0
   Else
       Return CInt(intInteger)
   End if
End Function

Answer 3

Private Sub readValue()
    Dim cSql As String
    Dim oCnn as OleDbConnection
    Dim oCmd as OleDbCommand
    Dim oDataReader as OleDbDataReader
    Dim valor as Integer

    oCnn.open()

    cSql = "SELECT FIELD_NAME FROM TABLE"
    oCmd = New OleDbCommand(cSql, oCnn)
    oReader = oCmd.executeReader

    if oReader.HasRows then
       oReader.read()
       valor = IIf(IsDBNull(oDataReader("FIELD_NAME")), 0, oDataReader("FIELD_NAME"))
    End If
End Sub

Vb.net将Integer DBNULL转换为0 - 错误

3 个答案: