未为类型“整数”和类型“dbnull”定义运算符“+”

Question

我正在尝试计算数据网格视图的总列、Oracle 中的数字数据类型、具有空值的数据网格视图列.....

Dim X As Integer
Dim y As Integer
For line As Integer = 0 To dgvAccDetail.RowCount - 1

    X = X + dgvAccDetail.Rows(line).Cells(4).Value

    y = y + dgvAccDetail.Rows(line).Cells(5).Value

Next
TXTVoucherDTotal.Text = X
txtvoucherCtotal.Text = y

但得到消息：

没有为“integer”类型和“dbnull”类型定义运算符“+”

.....请告诉我这段代码有什么问题。

Answer 1

这假设您将“DBNull”视为 0：

Dim X As Integer
Dim y As Integer
For line As Integer = 0 To dgvAccDetail.RowCount - 1

    X = X + If(IsDBNull(dgvAccDetail.Rows(line).Cells(4).Value),0,dgvAccDetail.Rows(line).Cells(4).Value)

    y = y + If(IsDBNull(dgvAccDetail.Rows(line).Cells(5).Value),0,dgvAccDetail.Rows(line).Cells(5).Value)

Next
TXTVoucherDTotal.Text = X.tostring
txtvoucherCtotal.Text = y.tostring

编辑：为避免在单元格中的值不是整数（而是将其计为 0）的情况下引发异常 - 正如 cmets 中的 Ctznkane525 所指出的那样。

    Dim X As Integer = 0
    Dim y As Integer = 0
    For line As Integer = 0 To dgvAccDetail.RowCount - 1

        If dgvAccDetail.Rows(line).Cells.Count >= 5 AndAlso TypeOf dgvAccDetail.Rows(line).Cells(4).Value Is Integer Then
            X = X + DirectCast(dgvAccDetail.Rows(line).Cells(4).Value, Integer)
        End If

        If dgvAccDetail.Rows(line).Cells.Count >= 6 AndAlso TypeOf dgvAccDetail.Rows(line).Cells(5).Value Is Integer Then
            y = y + DirectCast(dgvAccDetail.Rows(line).Cells(5).Value, Integer)
        End If

    Next

    TXTVoucherDTotal.Text = X.ToString
    txtvoucherCtotal.Text = y.ToString