Per maggior chiarezza posto il mio codice:

public void GridCarrello_ItemDataBound(object sender, DataGridItemEventArgs e)
{
DataRow Row;
string UID;
string idproduct;
string idshoppingcart;

HtmlImage ImgPreview;
HtmlAnchor LnkPreview;
PlaceHolder PlhVarianti;

if (e.Item.ItemType == ListItemType.Item || e.Item.ItemType == ListItemType.AlternatingItem || e.Item.ItemType == ListItemType.SelectedItem || e.Item.ItemType == ListItemType.EditItem)
{
//CONFIG DATAGRID STYLE
//e.Item.Attributes.Add("onmouseover", "this.style.backgroundColor='#DDEEFF'");
//e.Item.Attributes.Add("onmouseout", "this.style.backgroundColor='#FFFFFF'");
//e.Item.Style["cursor"] = "hand";

Row = ((DataRowView)(e.Item.DataItem)).Row;
UID = Row["IDShoppingCart"].ToString();
idproduct = Row["ProductId"].ToString();
idshoppingcart = Row["IDShoppingCart"].ToString();

ImgPreview = ((HtmlImage)(e.Item.Cells[1].FindControl("ImgPreview")));
LnkPreview = ((HtmlAnchor)(e.Item.Cells[1].FindControl("LnkPreview")));
PlhVarianti = ((PlaceHolder)(e.Item.Cells[1].FindControl("PlhVarianti")));

//RECUPERO L'IMMAGINE DEL MODELLO
SqlConnection conn;
conn = new SqlConnection(ConfigurationManager.ConnectionStrin gs["WFDB"].ConnectionString);
string SelectImgDefault = "SELECT * FROM V_PRODUCT_MEDIA WHERE IDProduct = " + idproduct + "";
SqlCommand CmdImgDefault = new SqlCommand(SelectImgDefault, conn);
conn.Open();
SqlDataReader ObjDRImgDefault = CmdImgDefault.ExecuteReader(System.Data.CommandBeh avior.CloseConnection);

if (ObjDRImgDefault.Read())
{
System.Drawing.Image realImage = System.Drawing.Image.FromStream(new System.IO.MemoryStream((byte[])ObjDRImgDefault["Thumbnail"]));
int altezza = realImage.Height * Convert.ToInt32(ConfigurationManager.AppSettings["FattoreScala"]) / 100;
int lunghezza = realImage.Width * Convert.ToInt32(ConfigurationManager.AppSettings["FattoreScala"]) / 100;

ImgPreview.Height = altezza;
ImgPreview.Width = lunghezza;
ImgPreview.Src = "Image.aspx?idproduct=" + idproduct + "&IdImage=" + ObjDRImgDefault["IdImage"].ToString() + "&ScaleFactor=" + ConfigurationManager.AppSettings["FattoreScalaDefault"] + "";
LnkPreview.HRef = "Image.aspx?idproduct=" + idproduct + "&IdImage=" + ObjDRImgDefault["IdImage"].ToString() + "&ScaleFactor=" + ConfigurationManager.AppSettings["FattoreScalaDefault"] + "";
}

ObjDRImgDefault.Close();
conn.Close();

//************************************************** ********
//COSTRUZIONE MATRICE VARIANTI
//************************************************** ********
Table VariantTable = new System.Web.UI.WebControls.Table();
VariantTable.BorderWidth = 1;
VariantTable.CssClass = "Varianti";
VariantTable.GridLines = GridLines.Both;
VariantTable.CellPadding = 0;
VariantTable.CellSpacing = 0;
VariantTable.Width = Unit.Percentage(98);

//REPERIMENTO DEI COLORI
SqlConnection conn_color;
conn_color = new SqlConnection(ConfigurationManager.ConnectionStrin gs["WFDB"].ConnectionString);
string SelectColor = "SELECT StyleAssociations.Product AS IDProduct, StyleAssociations.Color AS IDColor, Colors.Name, Colors.Red, Colors.Green, Colors.Blue FROM StyleAssociations INNER JOIN Colors ON StyleAssociations.Color = Colors.Id GROUP BY StyleAssociations.Color, StyleAssociations.Product, Colors.Name, Colors.Red, Colors.Green, Colors.Blue HAVING (StyleAssociations.Product = " + idproduct + ")";
SqlCommand CmdColor = new SqlCommand(SelectColor, conn_color);
conn_color.Open();
SqlDataReader ObjDRColor = CmdColor.ExecuteReader(System.Data.CommandBehavior .CloseConnection);

TableRow tr = new TableRow();

//PRIMA CELLA VUOTA
TableCell tdv = new TableCell();
tdv.Width = Unit.Percentage(10);
tdv.Text = "";
tdv.VerticalAlign = VerticalAlign.Middle;
tr.Cells.Add(tdv);

ArrayList ListColor = new ArrayList();

while (ObjDRColor.Read())
{
ListColor.Add(ObjDRColor["IDColor"].ToString());
TableCell td = new TableCell();
td.Width = Unit.Percentage(10);
td.Text = /*ObjDRColor["Name"].ToString().ToLower() + */ "<div style='background-color: " + System.Drawing.ColorTranslator.ToHtml(System.Drawi ng.Color.FromArgb(Int32.Parse(ObjDRColor["Red"].ToString()), Int32.Parse(ObjDRColor["Green"].ToString()), Int32.Parse(ObjDRColor["Blue"].ToString()))) + "; width: 10px; height: 10px;'></div>";
td.VerticalAlign = VerticalAlign.Middle;
tr.Cells.Add(td);
}
ObjDRColor.Close();
conn_color.Close();

//INTESTAZIONE DEI TOTALI DELLE QUANTITA'
TableCell tdIntTotal = new TableCell();
tdIntTotal.Width = Unit.Percentage(10);
tdIntTotal.Text = "TOTALE";
tdIntTotal.VerticalAlign = VerticalAlign.Middle;
tr.Cells.Add(tdIntTotal);

//AGGIUNGO LE CELLE COLORI ALLA TABELLA
VariantTable.Rows.Add(tr);

//REPERIMENTO DELLE TAGLIE
SqlConnection conn_size;
conn_size = new SqlConnection(ConfigurationManager.ConnectionStrin gs["WFDB"].ConnectionString);
string SelectSize = "SELECT StyleAssociations.Product AS IDProduct, StyleAssociations.Size AS IDSize, Sizes.Name AS Size FROM StyleAssociations INNER JOIN Sizes ON StyleAssociations.Size = Sizes.Id GROUP BY StyleAssociations.Product, StyleAssociations.Size, Sizes.Name HAVING (StyleAssociations.Product = " + idproduct + ")";
SqlCommand CmdSize = new SqlCommand(SelectSize, conn_size);
conn_size.Open();
SqlDataReader ObjDRSize = CmdSize.ExecuteReader(System.Data.CommandBehavior. CloseConnection);
while (ObjDRSize.Read())
{
TableRow trsize = new TableRow();
TableCell tdsize = new TableCell();
tdsize.Width = Unit.Percentage(10);
tdsize.Text = ObjDRSize["Size"].ToString().ToUpper();
tdsize.VerticalAlign = VerticalAlign.Middle;
trsize.Cells.Add(tdsize);

//REPERIMENTO DELLE QUANTITA'
for (int j = 0; j < ListColor.Count; j++)
{
TableCell tdquantity = new TableCell();
tdquantity.Width = Unit.Percentage(10);

SqlConnection conn_quantity;
conn_quantity = new SqlConnection(ConfigurationManager.ConnectionStrin gs["WFDB"].ConnectionString);
string SelectQuantity = "SELECT * FROM STYLEASSOCIATIONS WHERE Product = " + idproduct + " AND COLOR=" + ListColor[j].ToString() + " AND SIZE=" + ObjDRSize["IDSize"].ToString() + "";
SqlCommand CmdQuantity = new SqlCommand(SelectQuantity, conn_quantity);
conn_quantity.Open();
SqlDataReader ObjDRQuantity = CmdQuantity.ExecuteReader(System.Data.CommandBehav ior.CloseConnection);
if (ObjDRQuantity.Read())
{
if (ObjDRQuantity["Quantity"] != DBNull.Value)
{

tdquantity.Text = ObjDRQuantity["Quantity"].ToString(); /* + "<input type=text size=3 class=InputClass>"; */

//TODO: DA PROVARE
ArrayList ListQuantityCode = new ArrayList();
string QuantityCode = "";
SqlConnection connQuantityCode;
connQuantityCode = new SqlConnection(ConfigurationManager.ConnectionStrin gs["WFDB"].ConnectionString);
string SelectQuantityCode = "SELECT ASPNETQUANTITYCODE FROM SHOPPINGCART_PRODUCTS WHERE IDShoppingCart = " + idshoppingcart + "";
SqlCommand CmdQuantityCode = new SqlCommand(SelectQuantityCode, connQuantityCode);
connQuantityCode.Open();
SqlDataReader ObjDRQuantityCode = CmdQuantityCode.ExecuteReader(System.Data.CommandB ehavior.CloseConnection);

if (ObjDRQuantityCode.Read())
{
if (ObjDRQuantityCode["ASPNETQUANTITYCODE"] != DBNull.Value)
{
ListQuantityCode.Add(ObjDRQuantityCode["ASPNETQUANTITYCODE"].ToString());
}
}
ObjDRQuantityCode.Close();
connQuantityCode.Close();


TextBox qty = new TextBox();
qty.ID = "Crr_" + ListColor[j].ToString() + "_" + ObjDRSize["IDSize"].ToString();



//DEVO EFFETTUARE QUI LA PROCEDURA PER RECUPERARE I VALORI DEI MIEI TEXT BOX?
//DEVO EFFETTUARE QUI LA PROCEDURA PER SALVARE I VALORI DEI TEXTBOX?



qty.Text = "";
qty.CssClass = "InputClass";
qty.Width = 30;
tdquantity.Controls.Add(qty);


}
else
{
tdquantity.Text = "";
}
}
ObjDRQuantity.Close();
conn_quantity.Close();

tdquantity.VerticalAlign = VerticalAlign.Middle;

trsize.Cells.Add(tdquantity);
}

//CALCOLO TOTALI DELLE QUANTITA' PER COLOR/SIZE
TableCell tdtotal = new TableCell();
tdtotal.Width = Unit.Percentage(10);

int TotaleQuantita = 0;
for (int i = 0; i < ListColor.Count; i++)
{
SqlConnection conn_totalquantity;
conn_totalquantity = new SqlConnection(ConfigurationManager.ConnectionStrin gs["WFDB"].ConnectionString);
string SelectTotalQuantity = "SELECT * FROM STYLEASSOCIATIONS WHERE Product = " + idproduct + " AND COLOR=" + ListColor[i].ToString() + " AND SIZE=" + ObjDRSize["IDSize"].ToString() + "";
SqlCommand CmdTotalQuantity = new SqlCommand(SelectTotalQuantity, conn_totalquantity);
conn_totalquantity.Open();
SqlDataReader ObjDRTotalQuantity = CmdTotalQuantity.ExecuteReader(System.Data.Command Behavior.CloseConnection);
while (ObjDRTotalQuantity.Read())
{
if (ObjDRTotalQuantity["Quantity"] != DBNull.Value)
{
TotaleQuantita += Int32.Parse(ObjDRTotalQuantity["Quantity"].ToString());
tdtotal.Text = TotaleQuantita.ToString();
}
}
ObjDRTotalQuantity.Close();
conn_totalquantity.Close();
}

tdtotal.VerticalAlign = VerticalAlign.Middle;
//END TOTALI DELLE QUANTITA' PER COLOR/SIZE

trsize.Cells.Add(tdtotal);

//AGGIUNGO LE CELLE SIZE ALLA TABELLA
VariantTable.Rows.Add(trsize);
}
ObjDRSize.Close();
conn_size.Close();

//AGGIUNGO AL PLACEHOLDER LA TABELLA VARIANTI
PlhVarianti.Controls.Add(VariantTable);
//************************************************** ********
//END COSTRUZIONE MATRICE VARIANTI
//************************************************** ********
}
}