This is my code for displaying the gridview:
protected void Page_Load(object sender, EventArgs e)
{
if (!IsPostBack)
{
LoadCart();
}
}
protected void LoadCart()
{
string _connStr = ConfigurationManager.ConnectionStrings["CartDB"].ConnectionString;
SqlConnection SQLConn = new SqlConnection(_connStr);
SqlDataAdapter SQLAdapter = new SqlDataAdapter("SELECT M.menuItemName, M.menuItemImage,totalQuantity, M.menuItemPrice * totalQuantity Total_Price"
" FROM Cart C INNER JOIN itemSelected I ON C.username C.itemSelectedID = I.username I.itemSelectedID"
" INNER JOIN menuItem M ON I.menuItemID I.stallID = M.menuItemID M.stallID", SQLConn);
DataTable DT = new DataTable();
SQLAdapter.Fill(DT);
CartGridView.DataSource = DT;
CartGridView.DataBind();
LoadPrice();
}
protected void LoadPrice()
{
string _connStr = ConfigurationManager.ConnectionStrings["CartDB"].ConnectionString;
SqlConnection SQLConn = new SqlConnection(_connStr);
SqlCommand cmd = new SqlCommand("SELECT SUM(M.menuItemPrice * totalQuantity)tabulatedPrice"
" FROM Cart C INNER JOIN itemSelected I ON C.username C.itemSelectedID = I.username I.itemSelectedID"
" INNER JOIN menuItem M ON I.menuItemID I.stallID = M.menuItemID M.stallID", SQLConn);
SQLConn.Open();
lbl_TotalPrice.Text = cmd.ExecuteScalar().ToString();
SQLConn.Close();
}
This is my code in attempting to retrieve a specific row, but it returns null.
protected void CartGridView_RowCommand(object sender, GridViewCommandEventArgs e)
{
int result = 0;
Cart cart = new Cart();
GridViewRow row = CartGridView.SelectedRow;
string itemName = row.Cells[0].Text;
if (e.CommandName == "minusQuantity")
{
int quantity = int.Parse(row.Cells[3].Text) - 1;
if (quantity > 0)
{
cart.CartUpdateQuantity(quantity, itemName);
}
else
{
result = cart.CartDelete(itemName);
}
}
else if (e.CommandName == "addQuantity")
{
int quantity = int.Parse(row.Cells[3].Text) 1;
cart.CartUpdateQuantity(quantity, itemName);
}
Response.Redirect("UserShoppingCart.aspx");
}
And here is my aspx file:
<asp:Content ID="Content1" ContentPlaceHolderID="MainContent" runat="server">
<h1>Cart<table >
<tr>
<td style="width: 860px" >Product</td>
<td style="width: 698px">Images</td>
<td style="width: 1265px">Quantity</td>
<td>
Price</td>
</tr>
<tr>
<td colspan="4">
<asp:GridView ID="CartGridView" runat="server" AutoGenerateColumns="False" Width="1514px" OnRowCommand="CartGridView_RowCommand" >
<Columns>
<asp:BoundField HeaderText="Product" ShowHeader="False" DataField="menuItemName" />
<asp:BoundField HeaderText="Images" ShowHeader="False" DataField="menuItemImage" />
<asp:ButtonField ButtonType="Button" CommandName="minusQuantity" Text="-" />
<asp:BoundField HeaderText="Quantity" DataField="totalQuantity" />
<asp:ButtonField ButtonType="Button" CommandName="addQuantity" Text=" " />
<asp:BoundField DataField="Total_Price" HeaderText="Price" ShowHeader="False" />
</Columns>
</asp:GridView>
</td>
</tr>
<tr>
<td style="height: 39px; " colspan="3">Total:<asp:Label ID="lbl_TotalPrice" runat="server"></asp:Label>
</td>
<td style="height: 39px; width:50px;">
</td>
</tr>
</table>
</h1>
</asp:Content>
Could this issue arise from having an Sql Table as the datasource?
I have attempted,
string itemName = CartGridView.Rows[0].Cells[0].Text;
though it did work for the 1st row, I am uncertain on where to go next for the subsequent rows.
CodePudding user response：
The selected index change does not fire untill after the row command.
Why not just drop in a plane jane regular button? That way you can style the button, and just have a regular and simple click event for the button.
So, change your markup button to this:
<asp:TemplateField>
<ItemTemplate>
<asp:Button ID="cmdAddQty" runat="server" Text=" "
OnClick="cmdAddQty_Click" />
</ItemTemplate>
</asp:TemplateField>
So, just type in OnClick= (in the markup, and you be prompted for create new event). the result is a simple plain jane button click.
So, then the button click code can be:
protected void cmdAddQty_Click(object sender, EventArgs e)
{
Button btn = (Button)sender;
GridViewRow gRow = (GridViewRow)btn.NamingContainer;
Debug.Print("Row index click = " gRow.RowIndex);
int quantity = int.Parse(gRow.Cells[3].Text) 1;
// cart.CartUpdateQuantity(quantity, itemName);
}
So, you can easy pick up the row as per above.
And if you going to type "over and over" some sql, then build a helper rotuine to save world poverty, say like this:
protected void LoadCart()
{
string strSQL =
@"SELECT M.menuItemName, M.menuItemImage,totalQuantity, M.menuItemPrice * totalQuantity Total_Price
FROM Cart C
INNER JOIN itemSelected I ON C.username C.itemSelectedID = I.username I.itemSelectedID
INNER JOIN menuItem M ON I.menuItemID I.stallID = M.menuItemID M.stallID";
CartGridView.DataSource = MyRst(strSQL);
CartGridView.DataBind();
LoadPrice();
}
protected void LoadPrice()
{
string strSQL =
@"SELECT SUM(M.menuItemPrice * totalQuantity)tabulatedPrice
FROM Cart C
INNER JOIN itemSelected I ON C.username C.itemSelectedID = I.username I.itemSelectedID
INNER JOIN menuItem M ON I.menuItemID I.stallID = M.menuItemID M.stallID";
lbl_TotalPrice.Text = MyRst(strSQL).Rows[0][0].ToString();
}
DataTable MyRst(string strSQL)
{
DataTable rstData = new DataTable();
string strCon = ConfigurationManager.ConnectionStrings["CartDB"].ConnectionString;
using (SqlConnection conn = new SqlConnection(strCon))
{
using (SqlCommand cmdSQL = new SqlCommand(strSQL, conn))
{
cmdSQL.Connection.Open();
rstData.Load(cmdSQL.ExecuteReader());
}
}
return rstData;
}
Last but not least?
It is great to use and learn webforms. But, that is as long as you NOT paying for such a course, since webforms are now quite old, and while still rather popular? They are quite much now older and a legacy choice, one that been superseded by MVC and newer approaches.
So, I think WebForms are great, but NOT if you paying for books or a course in this day and age, and those peddling books and course(s) that teach webforms are really just using older outdated material, and thus taking a horrible advantage of un-suspecting students that don't know better.
Anyway, just drop in a plain jane regular button. You can dispense with row command and all that song and dance, as it not really required, and a simple regular button and button click event is easier anyway.