How to insert record to database when enter key is pressed inside TextBox in GridView in ASP.Net

I am using gridview with some columns few are :

<asp:templatefield headertext="Title Description" sortexpression="Description">
        <itemtemplate>
        <asp:Label id="Description"   runat="server" Text='<%# Bind("Description")%>'></asp:Label>
        </itemtemplate>
        <edititemtemplate>
        <asp:textbox id="Description" runat="server"  CssClass="form-control" text='<%# Bind("Description") %>' />
  </edititemtemplate>
    </asp:templatefield>
    <asp:templatefield headertext="Title Abbreviation" sortexpression="Abbreviation">
        <itemtemplate>
  <asp:Label id="Abbreviation"   runat="server" Text='<%# Bind("Abbreviation")%>'></asp:Label>
   </itemtemplate>
        <edititemtemplate>
  <asp:textbox id="Abbreviation" runat="server"  CssClass="form-control" text='<%# Bind("Abbreviation") %>' />
  </edititemtemplate>
    </asp:templatefield>
    <footertemplate> 
 <asp:Button ID="AddGridAddBTN" runat="server" OnClick="AddGridAddBTN_OnClick" Width="100%" CssClass="btn btn-info tooltips" Text="Add Row" /> 
 <asp:Button ID="AddGridSubmitBTN" runat="server" OnClick="AddGridSubmitBTN_OnClick" CssClass="btn btn-success tooltips" Width="100%" Text="Submit" />
</footertemplate>

Now this AddGridAddBTN Temporarily adds a data row to a grid but won't submit that data to database , however AddGridSubmitBTN Submits the data to DB through foreach loop .

Now my query is i want to provide user a functionality that when he gets focus on Abbreviation Text Box OR Description Box and he after typing some data Press ENTER KEY , This ENTER KEY would provide funcionality as a AddGridAddBTN Button , and when he presses SHIFT + ENTER , It works like AddGridSubmitBTN Button , also i want to make Abbreviation and Description Field to be filled must ! 

Moral is that :

ENTER KEY WOULD DO : Generate a temporary row with holding previous values as it is actually doing on AddGridAddBTN Button.

SHIFT + ENTER WOULD DO : Enter the whole grid data thorugh foreach loop as it is actually doing on AddGridSubmitBTN Button.

NOTE : I dont want to refresh my page on enter or shift enter pressing .

HELP : This grid is binded through SQL DATA SOURCE