Can anyone help ? I'm trying to update an access database via shopping cart but keep receiving the error
No value given for one or more required parameters. I'm using asp.net 1.1 with vb2003. Can anyone suggest where I'm going wrong - thanks ?


Sub AddToCart(sender As Object, e As EventArgs)

        Dim CartID As Integer
        Dim DateTime As Date
        Dim intProductID As Integer = sender.CommandArgument

        'Create a variable named Now and set it to the current date/time
        Dim Now as DateTime = DateTime.Now
        Dim s as String

        s = Now.ToString("MMM dd, yyyy")

        'Reference our cart
        'objDT = Session("CartID")

        'Create a new row
        objDR = objDT.NewRow
        objDR("CartID") = Session("CartID")
        objDR("ItemID") = intProductID
        objDR("DateTime") = Now.ToString("MMM dd yyyy") & " " & DateTime.Now.ToLongTimeString()

        objDT.Rows.Add(objDR)


        'add DT into session
        Session("Cart") = objDT

        'Bind data
        DGCart.DataSource = objDT
        DGCart.DataBind()


    End Sub

    Sub UpdateDbase(sender As Object, e As EventArgs)

        Dim dbCommand As System.Data.IDbCommand = New System.Data.OleDb.OleDbCommand

        Dim cmd as New OleDbCommand

        Dim CartID As Integer
        Dim DateTime As Date
        Dim intProductID As Integer

        With cmd.Parameters:
            .Add(New OleDbParameter("@CartID",CartID))
            .Add(New OleDbParameter("@ProductID",intProductID))
            .Add(New OleDbParameter("@DateTime", Now.ToString("MMM dd yyyy") & DateTime.Now.ToLongTimeString()))
        End With



        Dim myConnection = New OleDbConnection("Provider=Microsoft.Jet.OLEDB.4.0; Ole DB Services=-4; Data Source=F:\db\nwguitars.mdb")

        myConnection.Open()

        Dim myCommand = New OleDbCommand("INSERT INTO [tblCart] VALUES (@CartID,@intProductID,@DateTime)",myConnection)
        myCommand.ExecuteNonQuery()
        myConnection.Close()

    End Sub

Do you have a key constraint in the table you are inserting to that you are not populating? What line does the error come from? Do all the variables you using to populate your command parameters contain a value?

"The one language all programmers understand is profanity."

Hi,

All fields should be populated with the intCartID value as the primary key. Within the code I have created a datagrid (DGCart) just as a test to ensure the information is being passed when you click on the "Buy" button. I have a datalist set up that display all the products including each product's individual ProductID.

This message appears when you try to update the database. i suspect its becuase there does not seem to be any values to update the database but I'm not sure how to reference them . Thanks,

rsm42:

Now() is the name of a vb.net instrinsic function. Assign a different name in the Dim statement and see what happens.

Hope this helps.

Thanks for the reply.

Changed it but no different - any other ideas , thanks?

Well that makes sense, in your method UpdateDbase you define the variables but do not set the value to anything, thus you are trying to add variables that are null (err Nothing in vb) as your parameters.

To reference the values, if they are the same values that you use in your first method, place them in a session variable.

Dont declare variables with the name DateTime this is a type in VB and should be a reserved keyword. (Use some form of Hungarian notation e.g. iInteger for integers, sString for strings dtDate for datetime values etc.)


"The one language all programmers understand is profanity."

Thanks

As another test I actually removed the DateTime entry completely and still get this error. I take your point which sounds valid, but suspect the code is not passing the CartID and intProductID variables either - but struggling how to fix this.

No you dont understand. You are doing this:

        Dim CartID As Integer
        Dim DateTime As Date
        Dim intProductID As Integer

but you never assign values to these variables. You just automatically place them as parameters for your query, so the failure in the data being passed is that you are not passing it in anyway. The above variables literally have a value of null (Nothing), you need to pass values into them.

"The one language all programmers understand is profanity."

Thanks again for the reply.

Just to clarify I already have the data contained within a database and I have created a datalist which references the database and its values and displays the product items. What I am trying to do is to write some code so when a customer clicks on the "AddToCart" button, the values from the datalist are written to the table in the database.

I acknowledge that the current "AddToCart" sub routine is not trying to reference these values, but I'm not sure HOW to actually rectify this in terms of code. If you could offer some sample code that would be excellent.

Here's is my Datalist code for reference :

<asp:datalist id="DataList" runat="server" RepeatColumns="2" RepeatDirection="Horizontal">
                <ItemTemplate>
                    <table cellpadding="5" align="left" border="1">
                        <tr>
                            <td valign="top" width="180" height="140">
                                Product ID: <%# DataBinder.Eval(Container.DataItem, "intProductID") %>
                                <br />
                                <br />
                                Manufacturer: <%# DataBinder.Eval(Container.DataItem, "strMake") %>
                                <br />
                                <br />
                                Product Name: <%# DataBinder.Eval(Container.DataItem, "strProductName") %>
                                <br />
                                <br />
                                Colour: <%# DataBinder.Eval(Container.DataItem, "strColour") %>
                                <br />
                                <br />
                                Quantity In Stock: <%# DataBinder.Eval(Container.DataItem, "IntQuantityInStock") %>
                                <br />
                                <br />
                                Price: <%# DataBinder.Eval(Container.DataItem, "curSalePrice", "{0:c}") %>
                            </td>
                            <td align="center" width="110">
                                <img src='./images/<%# Databinder.Eval(Container.DataItem, "strImage") %>' valign="top" />
                            </td>
                            <td>
                                <asp:Button id="btnBuy" runat="server" Text="Buy" onclick="AddToCart" CommandArgument='<%# DataBinder.Eval(Container.DataItem, "intProductID")%>'></asp:Button>
                            </td>
                        </tr>
                    </table>
                </ItemTemplate>
            </asp:datalist>

In your AddToCart method you could just do: e.commandArgument which will return the value of that products Product ID then you could just grab the information from the database.

"The one language all programmers understand is profanity."