Selecting data from gridview using dropdownlist.

Question

User-1683638147 posted

Hi,

Im currently working on a delivery system for my school project. That's a dropdownlist inside my gridview , my gridview consist of deliveryID, orderID, address, and the status(dropdownlist).
so whenever I select "Received order",  an email will be send to the customer informing them that we received the order.
The email consist of their order id and a chunk of message.

The order id is inside the second column of my gridview, may I know how do I get that value ?

 protected void ddlStatus_SelectedIndexChanged(object sender, EventArgs e)
        {
            
            string deliveryId = GridView1.DataKeys[0].Value.ToString();
            string selectedValue = ((DropDownList)sender).SelectedValue;
        
            if (selectedValue == "Delivering in process") // i click this then send email
            {
                GridViewRow row = GridView1.SelectedRow;
                BLLDeliveryEmail del2 = new BLLDeliveryEmail();
                int result2 = 0;
                string Email1 = "[e-mail]";
                string subject1 = "Your delivery order is on the way!";
                string body1 = "test";
                string customername1 = "Test";

                GridViewRow row = GridView1.SelectedRow;
                int OrderID = int.Parse(row.Cells[1].Text); <<<<NULL REFERENCE ERROR>>>>
              
                result2 = del2.DeliveryEmail2(Email1, subject1, body1, customername1, OrderID);
            }

        }


           
           

I've tried using row.Cells[1], but its giving a null reference error. 

And the same problem goes to the deliveryId

string deliveryId = GridView1.DataKeys[0].Value.ToString();

This only give me the value from the first column and first row only. I cant retrieve the deliveryId value according to which row the dropdownlist is .

Thank you!

Answer 1

User2103319870 posted

The order id is inside the second column of my gridview, may I know how do I get that value ?

You need to find the row based on the dropdownlist control which triggered the seleccted index changed event like given below

 protected void ddlStatus_SelectedIndexChanged(object sender, EventArgs e)
        {
            
            //Get the dropdownlist which triggerd the selecctedindexchanged event
            DropDownList ddl = (DropDownList)sender;
            //Get the row based on the dropdownlist
            GridViewRow row = (GridViewRow)ddl.NamingContainer;
            //string deliveryId = GridView1.DataKeys[0].Value.ToString();
            string selectedValue = ((DropDownList)sender).SelectedValue;
        
            if (selectedValue == "Delivering in process") // i click this then send email
            {
                //GridViewRow row = GridView1.SelectedRow;
                BLLDeliveryEmail del2 = new BLLDeliveryEmail();
                int result2 = 0;
                string Email1 = "[e-mail]";
                string subject1 = "Your delivery order is on the way!";
                string body1 = "test";
                string customername1 = "Test";

                //GridViewRow row = GridView1.SelectedRow;
                int OrderID = int.Parse(row.Cells[1].Text); //<<<<NULL REFERENCE ERROR>>>>
              
                result2 = del2.DeliveryEmail2(Email1, subject1, body1, customername1, OrderID);
            }

        }

Answer 2

User61956409 posted

Hi vodaaaaaa,

You could refer to the following sample code.

<asp:GridView ID="GridView1" runat="server" AutoGenerateColumns="false" DataKeyNames="deliveryId,orderId">

protected void ddlStatus_SelectedIndexChanged(object sender, EventArgs e)
{
    int rowindex = ((GridViewRow)((DropDownList)sender).NamingContainer).RowIndex;

    string deliveryId = GridView1.DataKeys[rowindex].Values[0].ToString();
    string orderId = GridView1.DataKeys[rowindex].Values[1].ToString();

    //or
    //string orderId = GridView1.Rows[rowindex].Cells[1].Text;
            
}

Best Regards,

Fei Han

Answer 3

User-1683638147 posted

thank you!!!