Question

VB.net

Protected Sub monthlyReportsUK_RowDataBound(ByVal sender As Object, ByVal e As GridViewRowEventArgs)

If e.Row.RowType = DataControlRowType.DataRow Then
   Dim rowTotal As Decimal = Convert.ToDecimal(DataBinder.Eval(e.Row.DataItem, "webShopTotal").ToString)
   grdTotal = grdTotal + rowTotal
End If

If e.Row.RowType = DataControlRowType.Footer Then
   Dim lbl As Label = DirectCast(e.Row.FindControl("lblwebsVal"), Label)
   lbl.Text = "£" + grdTotal.ToString("##,0.00")
End If

End Sub

HTML：

<asp:TemplateField HeaderText="webShopTotal">
<ItemTemplate>
    <asp:Label ID="lblamount" runat="Server" Text='<%# Eval("webShopTotal") %>' />
</ItemTemplate>
<FooterTemplate>
    <asp:Label ID="lblwebsVal" runat="server"></asp:Label>
</FooterTemplate>
</asp:TemplateField>

GridView的

Month   Value
Jan     NULL
Feb     NULL
Mar     15.00
Apr     10.00

我希望能够对这些值求和：

   Month   Value
    Jan     NULL
    Feb     NULL
    Mar     15.00
    Apr     10.00
   Total    25.00

但是，我收到错误Object cannot be cast from DBNull to other types.

有什么办法可以在页脚中添加忽略NULL值的总数吗？

Answer 1

试试这个

Protected Sub monthlyReportsUK_RowDataBound(ByVal sender As Object, ByVal e As GridViewRowEventArgs)

If e.Row.RowType = DataControlRowType.DataRow Then    
 If DataBinder.Eval(e.Row.DataItem, "webShopTotal").ToString IsNot Nothing AndAlso DataBinder.Eval(e.Row.DataItem, "webShopTotal").ToString IsNot DbNull.Value Then
   Dim rowTotal As Decimal = Convert.ToDecimal(DataBinder.Eval(e.Row.DataItem, "webShopTotal").ToString)
   grdTotal = grdTotal + rowTotal
 End Id
End If

If e.Row.RowType = DataControlRowType.Footer Then
   Dim lbl As Label = DirectCast(e.Row.FindControl("lblwebsVal"), Label)
   lbl.Text = "£" + grdTotal.ToString("##,0.00")
End If

End Sub

修改

首先，您应该始终使用System.Decimal.TryParse()而不是Convert.ToDecimal（）

Dim result = 0 Dim rowTotal As Decimal = Decimal.TryParse(DataBinder.Eval(e.Row.DataItem, "webShopTotal").ToString), out result)

VB.NET GridView忽略页脚总计中的空值

1 个答案: