How To Delete a Row in GridView?

How do I delete a row in a GridView?

Here's my code so far:
.aspx file

<asp:GridView id="gvProjCapitalNo"
      Runat="Server"
      AutoGenerateColumns="False"
      ShowFooter="True"
      Caption="<b></b>"
      CellPadding="0"
      BorderStyle="None"
      BorderWidth="1px"
      BackColor="White"
      Font-Size="10pt"
      EditRowStyle-HorizontalAlign="Left"
      HeaderStyle-BackColor="#707070"
      HeaderStyle-ForeColor="#FFFFFF"
      AlternatingRowStyle-ForeColor="#FFFFFF"
      AlternatingRowStyle-BackColor="#A0A0A0"
      FooterStyle-BackColor="#707070"
      FooterStyle-ForeColor="#FFFFFF"
      FooterStyle-Font-Size="7pt"
      AllowPaging="false"
      AllowSorting="true"
      Font-Names="Verdana"
      Width="350px"
      PageSize="25"
      BorderColor="#E7E7FF"
      GridLines="Horizontal"
      DataKeyNames="PROJ_REF_NBR">

  <Columns>
 
  <asp:CommandField ShowDeleteButton="true" />  
   
  <asp:BoundField
    DataField="PROJ_REF_NBR"
     Visible="false"
    HeaderText="Project ID">
      <FooterStyle BorderWidth="0px" />
  </asp:BoundField>
 
  <asp:TemplateField HeaderText="CAPITAL PROJECT NUMBER">
    <ItemTemplate>
        <asp:Label ID="lblCPN" runat="server"> <%#Container.DataItem("CAPITAL_PROJ_NBR")%></asp:Label>
    </ItemTemplate>    
  </asp:TemplateField>
 
  </Columns>
     <FooterStyle BackColor="#B5C7DE" Font-Size="7pt" ForeColor="#4A3C8C" />
     <HeaderStyle BackColor="#4A3C8C" ForeColor="#F7F7F7" Font-Bold="True" />
     <AlternatingRowStyle BackColor="#F7F7F7" ForeColor="#4A3C8C" />
     <RowStyle BackColor="#E7E7FF" ForeColor="#4A3C8C" />
     <SelectedRowStyle BackColor="#738A9C" Font-Bold="True" ForeColor="#F7F7F7" />
     <PagerStyle BackColor="#E7E7FF" ForeColor="#4A3C8C" HorizontalAlign="Right" />

</asp:GridView>

.aspx.vb file code:

Protected Sub gvProjCapitalNo_RowDeleting(ByVal sender As Object, ByVal e As System.Web.UI.WebControls.GridViewDeleteEventArgs) Handles gvProjCapitalNo.RowDeleting

        Dim PID As Integer = gvProjCapitalNo.DataKeys(0).Value
        Dim lCPN As Label = CType(gvProjCapitalNo.FindControl("lblCPN"), Label)

        ProjectDAC.ProjCapitalFundingDelete(lCPN.Text, PID)

    End Sub

ERROR MESSAGE IS: "Object reference not set to an instance of an object" on this function - ProjectDAC.ProjCapitalFundingDelete(lCPN.Text, PID)