ASP.Net My Updated Value From Drop Down List Doesn't Update/Display - html

Question

I have a 4 page ASP.NET form which is storing data in the session. A button on my 3rd page clears the session. All this is working fine but I'm having a problem updating a value on my confirmation page as it retains/displays my initial selected value and i cant figure out why.
1st Page HTML With DropDownList
<asp:DropDownList ID="ddlInnoc" runat="server" class="form-control">
<asp:ListItem Value="0">- - Please Select - -</asp:ListItem>
<asp:ListItem Value="Male">Male</asp:ListItem>
<asp:ListItem Value="Female">Female</asp:ListItem>
</asp:DropDownList>
1st Page Code Behind Which Re-displays Selected Value
protected void Page_Load(object sender, EventArgs e)
{
txtData1.Focus();
if (txtData1.Text == string.Empty && Session["pg1input"] != null)
{
txtData1.Text = Session["pg1input"].ToString();
}
if (Session["pg1dd"] != null)
{
ddlInnoc.SelectedValue = Session["pg1dd"].ToString();
}
//if (Session["pg1dd"].ToString() == "")
//{
// ddlInnoc.SelectedValue = Session["pg1dd"].ToString();
//}
}
protected void pg1button_Click(object sender, EventArgs e)
{
Session["pg1input"] = txtData1.Text;
Session["pg1dd"] = ddlInnoc.SelectedItem;
Response.Redirect("/Session/pg2.aspx");
}
Page 3 HTML Code
<div class="form-group">
<div class="col-xs-12">
<asp:Label ID="Label1" class="col-md-2 control-label" runat="server" Text="Name:"></asp:Label>
<div class="col-md-3 form-control-static">
<%=Session["pg1input"] %>
</div>
</div>
</div>
<div class="form-group">
<div class="col-xs-12">
<asp:Label ID="Label2" class="col-md-2 control-label" runat="server" Text="Sex:"></asp:Label>
<div class="col-md-3 form-control-static">
<%=Session["pg1dd"] %>
</div>
</div>
</div>
<div class="row">
<div class="col-sm-offset-4 col-xs-12">
<asp:LinkButton ID="pg1EditButton" runat="server" OnClick="pg1EditButton_Click" CssClass="btn btn-default">
<span aria-hidden="true" class="glyphicon glyphicon-pencil"></span> Edit
</asp:LinkButton>
</div>
</div>
Page 3 Edit Button Code Behind
protected void pg1EditButton_Click(object sender, EventArgs e)
{
Response.Redirect("/Session/pg1.aspx");
}
I suspect that its something to do with the code behind on my page 1 as all the other fields/radio buttons on the other pages retrieves and displays the updated value on my 3rd page.

Answer 1

You are setting it back to the value in your session on postback.
Add this to your Page_Load.
if (!IsPostBack)
{
//set values from session
}

Answer 2

Fix is
if (!IsPostBack)
{
if (ddlInnoc.SelectedValue != "0" && Session["pg1dd"] != null)
{
ddlInnoc.SelectedValue = Session["pg1dd"].ToString();
}
}