Please I; m trying to update records I loaded from db to text boxes. I'm stacked please help me

protected void Update_Click(object sender, EventArgs e)
      {
          ccObject = new ConnectionClass();
          if (!IsPostBack)
          {

              try
              {
                  ccObject.Query(" uspUpdateProductInventory");
                  ccObject.cmd.Parameters.AddWithValue("@QuantityToAdd", TbxQtytoAdd.Text);
                  ccObject.cmd.Parameters.AddWithValue("@ProductCode", TbxProductCode.Text);

                  ccObject.ExcuteQuery();

                  string SuccessMessage = "INVENTORY UPDATE SUCCESSFUL";
                  ClientScript.RegisterStartupScript(this.GetType(), "myalert", "alert('" + SuccessMessage + "');", true);
              }
              catch (Exception ex)
              {

                  throw ex;
              }
              finally
              {
                  ccObject.CloseConnection();

              }
          }




      }

ALTER PROCEDURE [dbo].[uspUpdateProductInventory]
	-- Add the parameters for the stored procedure here
	@QuantityToAdd int,
	@ProductCode varchar(50)
AS
BEGIN
	-- SET NOCOUNT ON added to prevent extra result sets from
	-- interfering with SELECT statements.
	SET NOCOUNT ON;

    -- Insert statements for procedure here
	UPDATE Product.Inventory set QuantityAtStore = QuantityAtStore + @QuantityToAdd WHERE ProductCode=@ProductCode
END

<div class="form-group">
                 <label for="productcode">Product Code</label>
                   <asp:TextBox ID="TbxProductCode" CssClass="form-control" runat="server" OnTextChanged="TbxProductCode_TextChanged" AutoPostBack="True"></asp:TextBox>
                            <asp:RequiredFieldValidator ID="RfvProductCode" runat="server" ErrorMessage="Enter Product Code" ForeColor="Red" ControlToValidate="TbxProductCode" Display="Dynamic" ></asp:RequiredFieldValidator>
               </div>
               <div class="form-group">
                 <label for="ProductName">Product Name</label>
                   <asp:TextBox ID="TbxProductName" CssClass="form-control" ReadOnly="true" runat="server"></asp:TextBox>
               </div>
                 <div class="form-group">
                 <label for="Quantity in store">Quantity in Store</label>
                   <asp:TextBox ID="TbxQtyinStore" CssClass="form-control" ReadOnly="true" runat="server"></asp:TextBox>
               </div>
               <div class="form-group">
                 <label for="quantity to add">Quantity to Add</label>
                   <asp:TextBox ID="TbxQtytoAdd" CssClass="form-control" runat="server"></asp:TextBox>
                   <asp:RequiredFieldValidator ID="RfvQuantityToAdd" runat="server" ErrorMessage="Enter Quantity To Add" ForeColor="Red" ControlToValidate="TbxQtytoAdd" Display="Dynamic" ></asp:RequiredFieldValidator>
                   <asp:CompareValidator ID="CvQuantityToAdd" runat="server" ErrorMessage="invalid Quantity" ControlToValidate="TbxQtytoAdd" Operator="DataTypeCheck" Type="Integer" Display="Dynamic" ForeColor="Red" ></asp:CompareValidator>
               </div>