how to get values from grid view

Question

i am using following code to generate gridview.

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protected void Page_Load(object sender, EventArgs e)   
   {        
  if (!this.IsPostBack)   
       {            
  this.BindGrid();        
  }      }    

    private void BindGrid()    
  {   
       Entities entities = new Entities();
 Gridview1.DataSource = from customer in entities.SectorWisePoints.ToList()    
                                 select customer;            Gridview1.DataBind(); 
       }
 protected void OnRowDataBound(object sender, GridViewRowEventArgs e)  
    {          if (e.Row.RowType == DataControlRowType.DataRow)        
  {               
 CheckBox CHKBOX = (e.Row.FindControl("Released") as CheckBox);      
        CheckBox CHKBOX1 = (e.Row.FindControl("Released1") as CheckBox);  
                DropDownList ddlEmployee = (e.Row.FindControl("ddlEmp") as DropDownList);        
          DropDownList ddlEmployee2 = (e.Row.FindControl("ddlEmp2") as DropDownList);            
      var emp1 = _service.GetEmployeeDutyByEmployee_Id(MyUser.Employee_Id).LastOrDefault();      
            var EmpList = _service.GetAllEmployeeDuty().OrderByDescending(x => x.EndDate).GroupBy(x => x.Employee_Id).Select(x => x.First()).ToList();    
              var empList = EmpList.Where(X => X.ToSector_Id == emp1.ToSector_Id).ToList();              
    ddlEmployee.Bind(empList, "EmployeeIdName", "Employee_Id");  
                ddlEmployee2.Bind(empList, "EmployeeIdName", "Employee_Id");       
           }      } 

aspx code is

<asp:GridView ID="Gridview1" ControlStyle-BackColor="#ccccff" CssClass="col-sm-10" runat="server"   AutoGenerateColumns="false" OnRowDataBound="OnRowDataBound"            
              >                  
       <Columns>                 
                                         <asp:TemplateField HeaderText="PointName">         
                        <ItemTemplate>                               
      <asp:Label ID="lblPointName"  runat="server" Text='<%# Eval("Name")%>'> ></asp:Label>    
                             </ItemTemplate>                             </asp:TemplateField>    
                             <asp:TemplateField HeaderText="Employee">                         
        <ItemTemplate>                            
         <asp:DropDownList ID="ddlEmp" runat="server" OnSelectedIndexChanged="ddlEmp_SelectedIndexChanged" AutoPostBack="true"></asp:DropDownList>  
                               </ItemTemplate>                  
           </asp:TemplateField>                          
    <asp:TemplateField HeaderText="Released">            
                     <ItemTemplate>                      
               <asp:CheckBox  runat="server" ID="Released"/>  
                               </ItemTemplate>                
                                             </asp:TemplateField>   
                          <asp:TemplateField HeaderText="PointName">
 <ItemTemplate>                                   
  <asp:Label ID="lblPointName1"  runat="server" Text='<%# Eval("Name")%>'>></asp:Label>               
                  </ItemTemplate>                         
    </asp:TemplateField>                               
 <asp:TemplateField HeaderText="Employee">             
                    <ItemTemplate>                     
                <asp:DropDownList ID="ddlEmp2" runat="server" OnSelectedIndexChanged="ddlEmp_SelectedIndexChanged" AutoPostBack="true"></asp:DropDownList>      
                           </ItemTemplate>                       
                                       </asp:TemplateField>      
                       <asp:TemplateField HeaderText="Released"> 
                                <ItemTemplate>                   
                  <asp:CheckBox  runat="server" ID="Released1"/> 
                                </ItemTemplate>                  
                                            </asp:TemplateField> 
                        </Columns>            
         </asp:GridView> 

i want to save point name and selected employee on this selected event ,but i am unable to gat values,i am trying following code ,its give exception

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protected void ddlEmp_SelectedIndexChanged(object sender, EventArgs e)  
  {        DropDownList ddl1 = (DropDownList)Gridview1.FindControl("ddlEmp");   

     string Emp1 = ((DropDownList)Gridview1.SelectedRow.FindControl("ddlEmp")).SelectedItem.Value;     
   string Emp2 = ((DropDownList)Gridview1.SelectedRow.FindControl("ddlEmp")).SelectedItem.Value;      
  string pointname = ((Label)Gridview1.SelectedRow.FindControl("lblPointName")).Text;      
  string pointname1 = ((Label)Gridview1.SelectedRow.FindControl("lblPointName")).Text;    }