在VB.Net Gridview中添加总数 [英] Add total in VB.Net Gridview

问题描述

我尝试了以下方法：

 < asp：GridView ID =GVrunat =server
 DataSourceID =SqlQueryEmptyDataText =No data> 
<列> 
< asp：BoundField DataField =WeekdayFooterText =HeaderText =Weekday/> 
< asp：BoundField DataField =VolumeDataFormatString ={0：N0}
 FooterText =。 HeaderText =音量/> 
< /列> 
< / asp：GridView> 
 
 
受保护的子GV_rowdatabound（sender As Object，e As GridViewRowEventArgs）处理GV.RowDataBound 
 Dim Volume as integer = 0 
对于每个r As GridViewRow在GV中。行
如果r.RowType = DataControlRowType.DataRow Then 
 Volume = Volume + CDec（r.Cells（1）.Text）
 End If 
 Next 
 GV。 FooterRow.Cells（1）。文本= Math.Round（音量，0）
结束子
  

这给了我一个错误信息：

对象引用未设置为对象实例

I接下来的页面中的建议，我改变了代码：
试图总gridview在asp中

  Sub GV_WeekSumary_rowcreated（ByVal sender As Object，ByVal e As GridViewRowEventArgs）
 Dim Volume as integer = 0 
对于每个r As GridViewRow在GV.Rows中
如果r.RowType = DataCont rolRowType.DataRow Then 
 Volume = Volume + CDec（r.Cells（1）.Text）
 End If 
 Next 
 
如果e.Row.RowType = DataControlRowType .Footer然后
 e.Row.Cells（1）。文本= Math.Round（音量，0）
结束如果
结束子
  

这不会产生错误，但页脚不会显示任何值。

已经尝试过以下内容：

  Protected Sub Page_Load（ByVal sender As Object，ByVal e As System.EventArgs）Handles Me.Load 
 Dim Volume as integer = 0 
 For Each r As GridViewRow In GV.Rows 
 If r.RowType = DataControlRowType.DataRow Then 
 Volume = Volume + CDec（r.Cells（ 1）.Text）
 End If 
 Next 
 GV.FooterRow.Cells（1）.Text = Math.Round（Volume，0）
 GV.DataBind（）
结束子
  

在页脚仍然没有值，但是当我debbug它我可以看到，页脚被assisgned价值我需要。为什么它不显示在网站上？

任何想法如何让这个工作？

。解决方案

您必须使用数据绑定事件

试试这个：

  Protected Sub GV_DataBound（ByVal sender As Object，ByVal e As System.EventArgs）处理GV.DataBound 
 Dim Volume As Decimal = 0 
 For Each r作为GridViewRow在GV.Rows 
如果r.RowType = DataControlRowType.DataRow然后
 Volume + = Convert.ToDecimal（r.Cells（1）.Text）
 End If 
 Next 
 GV.FooterRow.Cells（1）.Text = Math.Round（Volume，0）.ToString（）
 End Sub 
  

I can not manage to get the gridview display the total in a footer

I've tried the following:

<asp:GridView ID="GV" runat="server" 
    DataSourceID="SqlQuery" EmptyDataText="No data">
    <Columns>
        <asp:BoundField DataField="Weekday" FooterText=" " HeaderText="Weekday" />
        <asp:BoundField DataField="Volume" DataFormatString="{0:N0}" 
            FooterText="." HeaderText="Volume" />            
    </Columns>
 </asp:GridView>


Protected Sub GV_rowdatabound(sender As Object, e As GridViewRowEventArgs) Handles GV.RowDataBound
    Dim Volume as integer = 0
    For Each r As GridViewRow In GV.Rows
        If r.RowType = DataControlRowType.DataRow Then
            Volume = Volume + CDec(r.Cells(1).Text)
        End If
    Next
    GV.FooterRow.Cells(1).Text = Math.Round(Volume , 0)
End Sub

This gives me an error messages:

Object reference not set to an instance of an object

I followed advice in the following page and I changed the code: trying to total gridview in asp

Sub GV_WeekSumary_rowcreated(ByVal sender As Object, ByVal e As GridViewRowEventArgs)
    Dim Volume as integer = 0
    For Each r As GridViewRow In GV.Rows
        If r.RowType = DataControlRowType.DataRow Then
            Volume = Volume + CDec(r.Cells(1).Text)
        End If
    Next

    If e.Row.RowType = DataControlRowType.Footer Then
        e.Row.Cells(1).Text = Math.Round(Volume , 0)
    End If
End Sub

This does not give an error, but the footer does not show any value.

I've tried also the following:

Protected Sub Page_Load(ByVal sender As Object, ByVal e As System.EventArgs) Handles Me.Load
    Dim Volume as integer = 0
    For Each r As GridViewRow In GV.Rows
        If r.RowType = DataControlRowType.DataRow Then
            Volume = Volume + CDec(r.Cells(1).Text)
        End If
    Next
    GV.FooterRow.Cells(1).Text = Math.Round(Volume, 0)
    GV.DataBind()
End Sub

Still no value in the footer, but when I debbug it I can see that footer is assisgned the value I need. Why it is not displayed in the website?

Any idea how I can get this to work?

解决方案

You must use DataBound event.

Try this:

Protected Sub GV_DataBound(ByVal sender As Object, ByVal e As System.EventArgs) Handles GV.DataBound
    Dim Volume As Decimal = 0
    For Each r As GridViewRow In GV.Rows
        If r.RowType = DataControlRowType.DataRow Then
            Volume += Convert.ToDecimal(r.Cells(1).Text)
        End If
    Next
    GV.FooterRow.Cells(1).Text = Math.Round(Volume, 0).ToString()
End Sub

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