Save Gridview Cell to database using asp and c#

Question

I have som textboxes and a button when pressing button, i do this
private DataTable dt = new DataTable();

        private void addassigment()
        {
            if (Session["DataTable"] != null)
            {
               
                dt = (DataTable) Session["DataTable"];    
            }
            else
            {
                dt.Columns.Add("From");
                dt.Columns.Add("To");
                dt.Columns.Add("Area");
                dt.Columns.Add("Sector");
                dt.Columns.Add("CompanyName");
                dt.Columns.Add("Description");
                dt.Columns.Add("References");
                dt.Columns.Add("Tools");
                dt.Columns.Add("Technology");
                //dt.Columns.Clear();
            }
          
 string sToolsValue = string.Empty;
            string sTechnologyvalue = string.Empty;
            DataRow dr = dt.NewRow();
         
            dr["From"] = TextBoxFrom.Text;
            dr["To"] = TextBoxTo.Text;
            dr["Area"] = TextBoxArea.Text;
            dr["Sector"] = TextBoxSector.Text;
            dr["CompanyName"] = TextBoxCompanyName.Text;
            dr["Description"] = TextBoxDescription.Text;
            dr["References"] = TextBoxReferences.Text;
           
           
            for (int i = 0; i < ListBoxAssignmentTools.Items.Count; i++)
            {

                sToolsValue += ListBoxAssignmentTools.Items[i];
               
            }

            for (int i = 0; i < ListBoxAssignmentTechnology.Items.Count; i++)
            {
                sTechnologyvalue += ListBoxAssignmentTechnology.Items[i];
               
            }
            dr["Tools"] = sToolsValue;
            dr["Technology"] = sTechnologyvalue;
           
             dt.Rows.Add(dr);
            Session["DataTable"] = dt;
            GridViewAllAssigments.DataSource = dt;
            GridViewAllAssigments.DataBind();

//This add the textbox values to the gridview

The asp code for the gridview

  <Columns>
                                                   
                                               <asp:TemplateField HeaderText="From">
                                               <ItemTemplate>
                                               <asp:Label ID="From"  runat="server" Text='<%# DataBinder.Eval(Container.DataItem,"From")%>' />
                                                </ItemTemplate>
                                                </asp:TemplateField>
                                            

                                                <asp:TemplateField HeaderText="To">
                                               <ItemTemplate>
                                               <asp:Label ID="To" runat="server" Text='<%# DataBinder.Eval(Container.DataItem,"To")%>' />
                                                </ItemTemplate>
                                                </asp:TemplateField>
                                               
                                                <asp:TemplateField HeaderText="Area">
                                               <ItemTemplate>
                                               <asp:Label ID="Area" runat="server" Text='<%# DataBinder.Eval(Container.DataItem,"Area")%>' />
                                                </ItemTemplate>
                                                </asp:TemplateField>
                                               
                                                <asp:TemplateField HeaderText="Sector">
                                               <ItemTemplate>
                                                   <asp:Label ID="Sector" runat="server" Text='<%# DataBinder.Eval(Container.DataItem,"Sector")%>' />
                                                </ItemTemplate>
                                                </asp:TemplateField>
                                               
                                                <asp:TemplateField HeaderText="Company name">
                                               <ItemTemplate>
                                               <asp:Label ID="CompanyName" runat="server" Text='<%# DataBinder.Eval(Container.DataItem,"CompanyName")%>'/>
                                                </ItemTemplate>
                                                </asp:TemplateField>
                                              
                                                <asp:TemplateField HeaderText="Description">
                                               <ItemTemplate>
                                               <asp:Label ID="Description" runat="server" Text='<%# DataBinder.Eval(Container.DataItem,"Description")%>'/>
                                                </ItemTemplate>
                                                </asp:TemplateField>
                                               
                                                <asp:TemplateField HeaderText="Tools">
                                               <ItemTemplate>
                                              <asp:Label ID="Tools" runat="server" Text='<%# DataBinder.Eval(Container.DataItem,"Tools")%>'/>
                                                </ItemTemplate>
                                                </asp:TemplateField>
                                               
                                                <asp:TemplateField HeaderText="Technology">
                                               <ItemTemplate>
                                               <asp:Label ID="Technology" runat="server" Text='<%# DataBinder.Eval(Container.DataItem,"Technology")%>'/>
                                                </ItemTemplate>
                                                </asp:TemplateField>
                                               
                                                <asp:TemplateField HeaderText="References">
                                               <ItemTemplate>
                                               <asp:Label ID="References" runat="server" Text='<%# DataBinder.Eval(Container.DataItem,"References")%>'/>
                                                </ItemTemplate>
                                                </asp:TemplateField>

                                                </Columns>

// After that i want to save the gridview cells to sql
var emp=new EMPLOYEE();
foreach (GridViewRow gvRowAssigment in GridViewAllAssigments.Rows)
            {
              

                var emp_assig_ref = new EMPLOYEES_ASSIGMENT_REFERENCE();
                Label lb =(Label) (gvRowAssigment.Cells[8].FindControl("Reference"));
                emp_assig_ref.reference_name = lb.Text;
                emp_assig_ref.reference_id = new Random().Next();

                var emp_assig_teh = new EMPLOYEES_ASSIGMENT_TECHNOLOGY();
                Label lb1 = (Label)(gvRowAssigment.Cells[7].FindControl("Technology"));
                emp_assig_teh.technology_name = lb1.Text;

                emp_assig_teh.assigment_technology_id = new Random().Next();

                var emp_assig_tools = new EMPLOYEES_ASSIGMENT_TOOLS();
                Label lb2 = (Label)(gvRowAssigment.Cells[6].FindControl("Tools"));
                emp_assig_tools.tools_name = lb2.Text;
                emp_assig_tools.assigment_tools_id = new Random().Next();



               

                var emp_assigment=new EMPLOYEES_ASSIGNMENT();

                Label lb3 = (Label) (gvRowAssigment.Cells[0].FindControl("From"));


                emp_assigment.from_date = lb3.Text;

                Label lb4 = (Label)(gvRowAssigment.Cells[1].FindControl("To"));
                emp_assigment.to_date = lb4.Text;
                Label lb5 = (Label)(gvRowAssigment.Cells[2].FindControl("Area"));
                emp_assigment.area = lb5.Text;
                Label lb6 = (Label)(gvRowAssigment.Cells[3].FindControl("Sector"));
                emp_assigment.sector = lb6.Text;
               
                Label lb7 = (Label)(gvRowAssigment.Cells[4].FindControl("CompanyName"));
                emp_assigment.company_name = lb7.Text;
               Label lb8 = (Label)(gvRowAssigment.Cells[5].FindControl("Description"));
                emp_assigment.description = lb8.Text;


                    emp_assigment.employee_id = theEmp.employee_id;
                    emp_assigment.assigment_id = new Random().Next();


                    emp_assigment.EMPLOYEES_ASSIGMENT_TOOLS = emp_assig_tools;
                    emp_assigment.assigment_tools_id = emp_assig_tools.assigment_tools_id;
                   emp_assigment.EMPLOYEES_ASSIGMENT_TECHNOLOGY = emp_assig_teh;
                    emp_assigment.assigment_technology_id = emp_assig_teh.assigment_technology_id;
                    emp_assigment.EMPLOYEES_ASSIGMENT_REFERENCE = emp_assig_ref;
                    emp_assigment.reference_id = emp_assig_ref.reference_id;



                emp.EMPLOYEES_ASSIGNMENT.Add(emp_assigment);
            }

    db.AddToEMPLOYEES(emp);
            db.SaveChanges();

The problem is after saving i dont get the any values in the database och null on every cell, but i dont now why?