Gridview disappears when I click Edit

I am creating a page to add maintenance technicians to a sql express table. I want to be able to edit a gridview. I have added it and associated my stored procedures with the datasource. The problem is that when I click edit the gridview disappears. Below is my code for the page and the stored procedure.

ASPX Page
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<%@ Page Language="VB" MasterPageFile="~/masters/leftnavbar_maint_tasks.master" AutoEventWireup="false" CodeFile="technicians.aspx.vb" Inherits="maint_technicians" title="Untitled Page" %>
<asp:Content ID="Content1" ContentPlaceHolderID="cphMain" Runat="Server">
<h4>Add Technicians...</h4>
    <asp:formview datakeynames="id" datasourceid="srcTechs" defaultmode="Insert" id="frmAddTechs" runat="server">
        <insertitemtemplate>
            First Name:
            <asp:textbox id="txtfirst_name" runat="server" text='<%# Bind("first_name") %>'></asp:textbox><br />
            Last Name:
            <asp:textbox id="txtLastName" runat="server" text='<%# Bind("last_name") %>'></asp:textbox><br />
            <asp:linkbutton id="InsertButton" runat="server" causesvalidation="True" commandname="Insert"
                text="Insert"></asp:linkbutton>
            <asp:linkbutton id="InsertCancelButton" runat="server" causesvalidation="False" commandname="Cancel"
                text="Cancel"></asp:linkbutton>
        </insertitemtemplate>
    </asp:formview>
    <asp:sqldatasource id="srcTechs" runat="server" connectionstring="<%$ ConnectionStrings:conMaintTasks %>"
        insertcommand="sp_insert_tech" insertcommandtype="StoredProcedure" selectcommand="sp_select_tech" selectcommandtype="StoredProcedure" updatecommand="sp_update_tech" updatecommandtype="StoredProcedure">
        <insertparameters>
            <asp:parameter name="first_name" type="String" />
            <asp:parameter name="last_name" type="String" />
        </insertparameters>
        <updateparameters>
            <asp:parameter name="first_name" type="String" />
            <asp:parameter name="last_name" type="String" />
            <asp:parameter name="email" type="String" />
            <asp:parameter name="active" type="Boolean" />
            <asp:parameter name="original_id" type="Int32" />
            <asp:parameter name="original_first_name" type="String" />
            <asp:parameter name="original_last_name" type="String" />
            <asp:parameter name="original_email" type="String" />
            <asp:parameter name="original_active" type="Boolean" />
        </updateparameters>
        <deleteparameters>
            <asp:parameter name="original_id" type="Int32" />
            <asp:parameter name="original_first_name" type="String" />
            <asp:parameter name="original_last_name" type="String" />
            <asp:parameter name="original_email" type="String" />
            <asp:parameter name="original_active" type="Boolean" />
        </deleteparameters>
    </asp:sqldatasource>
<h4>Current Technicians...</h4>
<asp:gridview id="grdTechs" runat="server" e autogeneratecolumns="False" datakeynames="id"
        datasourceid="SqlDataSource1" allowsorting="True">
        <columns>
            <asp:commandfield showeditbutton="True" />
            <asp:boundfield datafield="id" headertext="id" insertvisible="False" readonly="True"
                sortexpression="id" visible="False" />
            <asp:boundfield datafield="first_name" headertext="First Name" sortexpression="first_name" />
            <asp:boundfield datafield="last_name" headertext="Last Name" sortexpression="last_name" />
            <asp:boundfield datafield="email" headertext="Email Address" sortexpression="email" />
            <asp:checkboxfield datafield="active" headertext="Active" sortexpression="active" />
        </columns>
    <rowstyle font-size="Small" />
    <headerstyle font-bold="True" />
    </asp:gridview>
    <asp:sqldatasource id="SqlDataSource1" runat="server" conflictdetection="CompareAllValues"
        connectionstring="<%$ ConnectionStrings:conMaintTasks %>" deletecommand="DELETE FROM [tech] WHERE [id] = @original_id AND [first_name] = @original_first_name AND [last_name] = @original_last_name AND [email] = @original_email AND [active] = @original_active"
        insertcommand="INSERT INTO [tech] ([first_name], [last_name], [email], [active]) VALUES (@first_name, @last_name, @email, @active)"
        oldvaluesparameterformatstring="original_{0}" selectcommand="SELECT * FROM [tech]"
        updatecommand="UPDATE [tech] SET [first_name] = @first_name, [last_name] = @last_name, [email] = @email, [active] = @active WHERE [id] = @original_id AND [first_name] = @original_first_name AND [last_name] = @original_last_name AND [email] = @original_email AND [active] = @original_active">
        <deleteparameters>
            <asp:parameter name="original_id" type="Int32" />
            <asp:parameter name="original_first_name" type="String" />
            <asp:parameter name="original_last_name" type="String" />
            <asp:parameter name="original_email" type="String" />
            <asp:parameter name="original_active" type="Boolean" />
        </deleteparameters>
        <updateparameters>
            <asp:parameter name="first_name" type="String" />
            <asp:parameter name="last_name" type="String" />
            <asp:parameter name="email" type="String" />
            <asp:parameter name="active" type="Boolean" />
            <asp:parameter name="original_id" type="Int32" />
            <asp:parameter name="original_first_name" type="String" />
            <asp:parameter name="original_last_name" type="String" />
            <asp:parameter name="original_email" type="String" />
            <asp:parameter name="original_active" type="Boolean" />
        </updateparameters>
        <insertparameters>
            <asp:parameter name="first_name" type="String" />
            <asp:parameter name="last_name" type="String" />
            <asp:parameter name="email" type="String" />
            <asp:parameter name="active" type="Boolean" />
        </insertparameters>
    </asp:sqldatasource>
   
</asp:Content>

ASPX.VB File
#####################################
Partial Class maint_technicians
    Inherits System.Web.UI.Page

End Class

Stored Procedure
###############################
ALTER PROCEDURE dbo.sp_update_tech
(
      @first_name varchar(50),
      @last_name varchar(50),
      @email varchar(50),
      @active bit,
      @Original_id int,
      @IsNull_first_name Int,
      @Original_first_name varchar(50),
      @IsNull_last_name Int,
      @Original_last_name varchar(50),
      @IsNull_email Int,
      @Original_email varchar(50),
      @IsNull_active Int,
      @Original_active bit,
      @id int
)
AS
      SET NOCOUNT OFF;
UPDATE [tech] SET [first_name] = @first_name, [last_name] = @last_name, [email] = @email, [active] = @active WHERE (([id] = @Original_id) AND ((@IsNull_first_name = 1 AND [first_name] IS NULL) OR ([first_name] = @Original_first_name)) AND ((@IsNull_last_name = 1 AND [last_name] IS NULL) OR ([last_name] = @Original_last_name)) AND ((@IsNull_email = 1 AND [email] IS NULL) OR ([email] = @Original_email)) AND ((@IsNull_active = 1 AND [active] IS NULL) OR ([active] = @Original_active)));
      
SELECT id, first_name, last_name, email, active FROM tech WHERE (id = @id)