Problem capturing value from cell in gridview using GridView1_RowUpdating in ASP.net(VB). Getting error below.

DEK 0

Line 73: 
Line 74:         'Compute Final Price
Line 75:         Dim ItemPrice As String = TryCast(GridView1.Rows(e.RowIndex).FindControl("Price"), TextBox).Text.ToString
Line 76:         hfFinalPrice.Value = hfItemQuanGrid.Value * ItemPrice
Line 77:

DEK 0

                                        <asp:GridView ID="GridView1" runat="server" AutoGenerateColumns="False" DataSourceID="SqlGetCart" DataKeyNames="Cart_ID" Width="1536px">
                                            <Columns>
                                                <asp:CommandField DeleteText="Remove from Cart" EditText="Edit Quantity&nbsp;&nbsp;&nbsp;&nbsp;Add/Edit Comment&nbsp;&nbsp;&nbsp;&nbsp;" UpdateText="Save Changes;&nbsp;&nbsp;&nbsp;" ShowDeleteButton="True" ShowEditButton="True" CancelText="Cancel Item" >
                                                <ControlStyle Font-Bold="True" Font-Names="helvetica" />
                                                </asp:CommandField>
                                                <asp:BoundField DataField="Member_ID" ReadOnly="True" HeaderText="MEM_ID" Visible="false" />
                                                <asp:BoundField DataField="Transaction_ID" ReadOnly="True" HeaderText="Trans_ID" Visible="False" />
                                                <asp:BoundField DataField="Cart_ID" ReadOnly="True" HeaderText="Cart_ID" Visible="False" />
                                                <asp:BoundField DataField="Item_ID" ReadOnly="True" HeaderText="Item_ID" Visible="True" />
                                                <asp:BoundField DataField="Item" HeaderText="Item" ReadOnly="True" />
                                                <asp:TemplateField HeaderText="Description" ItemStyle-Width="100px" ItemStyle-Wrap="true">
                                                    <ItemTemplate>
                                                        <asp:Label ID="Label10" runat="server" Text='<%# Bind("Add_Info")%>'  Width="100px"></asp:Label>
                                                    </ItemTemplate>
                                                    <ItemStyle Wrap="True" Width="100px"></ItemStyle>
                                                </asp:TemplateField>
                                                <asp:TemplateField HeaderText="Qty">
                                                    <EditItemTemplate>
                                                        <asp:TextBox ID="Quantity" runat="server" Text='<%# Eval("ItemQuan")%>' Width="30px" ReadOnly="false"></asp:TextBox>
                                                    </EditItemTemplate>
                                                    <ItemTemplate>
                                                        <asp:TextBox ID="Quantity" runat="server" Text='<%# Eval("ItemQuan")%>' Width="30px" ReadOnly="True"></asp:TextBox>
                                                    </ItemTemplate>
                                                </asp:TemplateField>
                                                <asp:BoundField DataField="Price" HeaderText="Total Price" ReadOnly="True" />
                                                <asp:TemplateField HeaderText="Comment (if any)">
                                                    <EditItemTemplate>
                                                        <asp:TextBox ID="tbComment" runat="server" Text='<%# Eval("ItemComment")%>' Width="300px" ReadOnly="false"></asp:TextBox>
                                                    </EditItemTemplate>
                                                    <ItemTemplate>
                                                        <asp:TextBox ID="tbComment" runat="server" Text='<%# Eval("ItemComment")%>' Width="300px" ReadOnly="True"></asp:TextBox>
                                                    </ItemTemplate>
                                                    <ItemStyle Wrap="True" Width="100px"></ItemStyle>
                                                </asp:TemplateField>
                                            </Columns>
                                            <HeaderStyle BackColor="#FFFFFF" Font-Names="Helvetica" Font-Size="Small" HorizontalAlign="Left" />
                                            <RowStyle BackColor="#CEEFBD" Font-Names="Helvetica" Font-Size="Small" HorizontalAlign="Center" />
                                        </asp:GridView>

DEK 0

    Private Sub GridView1_RowUpdating(sender As Object, e As GridViewUpdateEventArgs) Handles GridView1.RowUpdating
        'This code block hooks the Quantity column to determine current quantity in grid to determine if quantity has changed.
        'If the quantity has changed from quantity in datatable, the quantity on hand has to be updated in tblInventory to reflect change.

        hfCart_ID.Value = e.Keys("Cart_ID")

        Dim rowindex As Integer = CInt(e.RowIndex)
        Dim row As GridViewRow = GridView1.Rows(rowindex)

        'Get Item_ID of item to be updated in this order
        Dim ItemID As String = GridView1.Rows(e.RowIndex).Cells(4).Text
        hfItem_ID.Value = ItemID

        'Get quantity of item in the GridView1  
        Dim Quan As String = DirectCast(GridView1.Rows(e.RowIndex).FindControl("Quantity"), TextBox).Text.ToString
        hfItemQuanGrid.Value = Quan  'Current quantity in GridView

        'Get Item Comment in the Gridview1
        Dim ItemComment As String = DirectCast(GridView1.Rows(e.RowIndex).FindControl("tbComment"), TextBox).Text.ToString
        hfItemCommentGrid.Value = ItemComment 'Current Item Comment in Gridview

        'Get Price and compute Final Price
        Dim ItemPrice As String = DirectCast(row.Cells(5).FindControl("Price"), TextBox).Text.ToString
        hfFinalPrice.Value = hfItemQuanGrid.Value * ItemPrice

        'Update tblCart
        SqlUpdateCart.Update()
        'End If
        GridView1.DataBind()

Lan Huang-MSFT 25,866 Reputation points Microsoft Vendor

2023-03-24T07:07:44.3266667+00:00
Hi @DEK,

You need to provide error information so that we can better help you solve the problem.

I tested your code.

Your Price field is using BoundField, not textbox.

I think you should get the specific column.

And you need to calculate Price, you need to convert to the corresponding type.

Dim ItemPrice As Integer = Convert.ToInt32((row.Cells(8)).Text)

1 answer

AgaveJoe 26,141

You did not provide the error... Your code tries to multiple a string named ItemPrice by an unknown value (hfItemQuanGrid.Value). Convert ItemPrice and perhaps hfItemQuanGrid.Value to a numeric type using the TryParse() method.

Imports System.Data

Module Program
    Sub Main(args As String())
        Dim ItemPrice As String = "1.23"
        Dim Price As Decimal

        If (Decimal.TryParse(ItemPrice, Price)) Then
            Console.WriteLine("TryParse was successful.  The price is " & Price)
        Else
            Console.WriteLine("Unable to convert " & ItemPrice & " to a decimal")
        End If
    End Sub

End Module