View Data in GridView using StoredProcedure (WebForm ASP.NET)

There is a simple way to view data in gridview.
We manage it by using datasource and then choose your stored procedure.
But this time, I don't use it.
I make my grid view by drag an drop the gridview from toolbox.
This is my.aspx
<asp:GridView ID="gridviewKelas" runat="server" AutoGenerateColumns="False"  Width="100%" CssClass="table table-bordered table-striped" AllowPaging="true" OnRowUpdating="gridviewDataKaryawan_RowUpdating" DataKeyNames="Class_Id" OnRowEditing="gridviewKelas_RowEditing" OnRowCancelingEdit="gridviewKelas_RowCancelingEdit" OnRowDeleting="gridviewKelas_RowDeleting">
               
                <Columns>
                    <asp:TemplateField HeaderText="ID Kelas" ItemStyle-Width="150">
                        <ItemTemplate>
                            <asp:Label ID="lblClass_Id" runat="server" Text='<%# Eval("Class_Id") %>'></asp:Label>
                        </ItemTemplate>
                    </asp:TemplateField>

                    <asp:TemplateField HeaderText="Nama Kelas" ItemStyle-Width="150">
                        <ItemTemplate>
                            <asp:Label ID="lblClass_Name" runat="server" Text='<%# Eval("Class_Name") %>'></asp:Label>
                        </ItemTemplate>
                        <EditItemTemplate>
                            <asp:TextBox ID="txtClassName" runat="server" Text='<%# Eval("Class_Name") %>'></asp:TextBox>
                            <asp:RequiredFieldValidator ID="RequiredFieldValidatorAlamat" runat="server" ErrorMessage="Nama kelas tidak boleh kosong" ControlToValidate="txtClassName"></asp:RequiredFieldValidator>
                        </EditItemTemplate>
                    </asp:TemplateField>

                     <asp:TemplateField HeaderText="Status Kelas" ItemStyle-Width="150">
                        <ItemTemplate>
                            <asp:Label ID="lblStatus" runat="server" Text='<%# Eval("Status") %>'></asp:Label>
                        </ItemTemplate>
                        <EditItemTemplate>
                            <asp:TextBox ID="txtStatus" runat="server" Text='<%# Eval("Status") %>'></asp:TextBox>
                            <asp:RequiredFieldValidator ID="RequiredFieldValidatorNomorHP" runat="server" ErrorMessage="Status kelas tidak boleh kosong" ControlToValidate="txtStatus"></asp:RequiredFieldValidator>
                        </EditItemTemplate>
                    </asp:TemplateField>
                   
                   
                    <asp:CommandField ButtonType="Link" ShowEditButton="true" ShowDeleteButton="true" ItemStyle-Width="150"/>
                </Columns>
            </asp:GridView>

Then in my.aspx.cs while I reload the page I call the method that declare the stored procedure

BED_MANAGEMET_APP.Models.M_Class kelas = new Models.M_Class();
        protected void Page_Load(object sender, EventArgs e)
        {
           
            if (!IsPostBack)
            {
                BindData();
            }
        }

        private void BindData()
        {
            gridviewKelas.DataSource = kelas.GetDataAll(); << the method that call stored procedure
            gridviewKelas.DataBind();
        }

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:D :D