The GridView GridView1 fired event RowDeleting which wasnt handled

hi friends,i have a problem in my gridview control,actually i am having a gridview and bind the gridview with the database,in that gridview i provide a link button called delete,when i click the delete button its shows an error,after reloading the page the current record is deleted,but whenever the delete button is pressed its shows the following error

The GridView 'GridView1' fired event RowDeleting which wasn't handled.

but whenever i reload the project the record will be deleted,here is my code

<asp:GridView runat="server" AutoGenerateColumns="false"          ID="GridView1">         <Columns>             <asp:BoundField DataField="empname" HeaderText="EMPLOYEE NAME"                 SortExpression="empname" />                        <asp:TemplateField>                 <ItemTemplate>                     <asp:LinkButton runat="server" ID="lnkDelete"                         Text="Delete" CommandName="delete"                         CommandArgument='<%# DataBinder.Eval(Container.dataitem, "empid")%>'>                     </asp:LinkButton>                 </ItemTemplate>             </asp:TemplateField>         </Columns>     </asp:GridView>

  Protected Sub Page_Load(ByVal sender As Object, ByVal e As System.EventArgs) Handles Me.Load
       

        connection.ConnectionString = ("Data Source=RIFAYEE-PC;Initial Catalog=HumanResource;Integrated Security=True")

        cmd = New SqlCommand("select empid,empname from emp ORDER BY empid", connection)
        da = New SqlDataAdapter(cmd)
        dt.Clear()
        connection.Open()
        da.Fill(dt)
        If dt.Rows.Count > 0 Then
            GridView1.DataSource = dt
            GridView1.DataBind()
        Else
            Response.Write("no data found")
        End If
    End Sub

    Protected Sub GridView1_RowCommand(ByVal sender As Object, ByVal e As GridViewCommandEventArgs) Handles GridView1.RowCommand
        If (e.CommandName = "delete") Then
            Dim empid = e.CommandArgument.ToString
            deleteempid(empid)
        End If
    End Sub
    Private Sub deleteempid(ByVal empid As String)
        cmd = New SqlCommand("delete from emp where empid=@empid", connection)
        Dim empidparameter = New SqlParameter("@empid", empid)
        empidparameter.Value = empid
        cmd.Parameters.Add(empidparameter)
        cmd.ExecuteNonQuery()
        Response.Write("deleted successfully")
    End Sub