我如何在asp.net的datagridview列中显示总和

我有一个datagridview，用于显示交易记录。 datagridview中的一列是“amount”

girdview enter code here

                 <asp:Label ID="lblPayeeID1" runat="server" Text=''>         <asp:Label ID="lblPayeeCode" runat="server" Text=''>       Account head   <asp:Label ID="lblGrossType" runat="server" Text='' Wrap="true">    
 
 
 <asp:Label ID="txtGrossType" runat="server" Text='' CssClass="black_normal" Width="110px"> 
 
 
      Payee Amount   <asp:Label ID="lblPresentedAmount" runat="server" Text=' ' Wrap="true">    
 
 
 <asp:Label ID="txtPresentedAmount" runat="server" Text='' CssClass="black_normal" onblur="requiredCheck(this);" MaxLength="5" Width="110px"> 
 
 
         Approved Amount   <asp:Label ID="lblApproveAmount" runat="server" Text='' Wrap="true">    
 
 
 <asp:TextBox ID="txtApproveAmount" runat="server" Text='' CssClass="black_normal" onblur="requiredCheck(this);" MaxLength="5" Width="110px"> <ajaxToolkit:FilteredTextBoxExtender ID="fltrApprove" runat="server" FilterType="Custom" FilterMode="InvalidChars" InvalidChars="'abcdefghijklmnopqrstuvwxyz@!#$%^&*% ," TargetControlID="txtApproveAmount">  
 
 
         
 
 
 
 
 
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我的问题是，如何通过将gridview中的所有“金额”加到asp.net的文本框中来制作“GrandTotal”？

当我尝试下面的代码：

无法识别标签的ID（错误：不存在“lbltotal”）

请告诉我哪里做错了？

 int sum = 0; for (int i = 0; i < dataGridView1.Rows.Count; ++i) { sum += Convert.ToInt32(dataGridView1.Rows[i].Cells[2].Value); } lbltotal.text = sum.ToString(); 

如何解决这个问题？

  private void ComputeBySalesSalesID(DataSet dataSet) { // Presumes a DataTable named "Orders" that has a column named "Total." DataTable table; table = dataSet.Tables["Orders"]; // Declare an object variable. object sumObject; sumObject = table.Compute("Sum(Total)", "EmpID = 5"); //Find label GridViewRow footer = dgOpenBal.FooterRow; var lblTotal = (Label)footer.FindControl("lblTotal"); lblTotal.Text = sumObject.ToString(); } 

 private void ComputeBySalesSalesID(DataSet ds) { if (ds.Tables[0].Rows.Count > 0) { DataRow drSum = ds.Tables[0].Rows[0]; GridViewRow footer = dgOpenBal.FooterRow; var lblTotal = (Label)footer.FindControl("lblTotal"); lblTotal.Text = drSum["sum"].ToString(); } } 

  int sum = 0; for (int i = 0; i < dataGridView1.Rows.Count; ++i) { sum += Convert.ToInt32(dataGridView1.Rows[i].Cells[2].Value); } GridViewRow row = GridView1.FooterRow; ((Label)row.FindControl("lbltotal")).Text=sum.ToString();