Why radiobutton selection on C# server does not work?

I have a group radio buttons defined below. Assume using server side process OnCheckedChanged instead of client side, please see the server function DevSelected.

<asp:Panel ID="pldev" runat="server" GroupingText="Choose a Type" Width="370px">
<asp:RadioButton id="type1" Text="Device1" GroupName="device" AutoPostBack="true" OnCheckedChanged="DevSelected" runat="server" />
<asp:RadioButton id="type2" Text="Device2" GroupName="device" AutoPostBack="true" OnCheckedChanged="DevSelected" runat="server" />
<asp:RadioButton id="type3" Text="Device3" GroupName="device" AutoPostBack="true" OnCheckedChanged="DevSelected" runat="server" />
<asp:RadioButton id="type4" Text="Device4" GroupName="device" AutoPostBack="true" OnCheckedChanged="DevSelected" runat="server" />
</asp:Panel>


protected void DevSelected(object sender, System.EventArgs e)
{
        string aclick = (string)Session["TypeSelected"];
       
        if (aclick == "NoneSelected")    //Handles the initial click
        {
            MakeSwitch();
            if (type1.Checked)  aclick = "Type1Selected";
            if (type2.Checked)  aclick = "Type2Selected";
            if (type3.Checked)  aclick = "Type3Selected";
            if (type4.Checked)  aclick = "Type4Selected";
            Session.Add("TypeSelected", aclick);
        }
        else if (aclick != "NoneSelected")   //Handles the clicks after the initial clicking
        {
            if (MessageBox.Show("would you want to make a switch and ignore these data?", "Confirm Switch", MessageBoxButtons.YesNo) == DialogResult.Yes)
            {
                MakeSwitch();
            }
            else
            {
                //Recover the previos selected button selection if No/Cancel of the confirm box is chosen.
                if (aclick == "Type1Selected")  type1.Checked = true;
                if (aclick == "Type2Selected")  type2.Checked = true;
                if (aclick == "Type3Selected")  type3.Checked = true;
                if (aclick == "Type4Selected")  type4.Checked = true;
            }
        }
    }

I have the session variable TypeSelected initially set as "NoneSelected" at the application loading. The four radio buttons are unselected initially.

The above code works expected if Yes/Ok of the confirm box is chosen. But if No/Cancel of the confirm box is chosen, the previously selected radio button is not reselected, which means the following code does not work at all. But why? How can I make a radiobutton selection on C# server side?
                if (aclick == "Type1Selected") type1.Checked = true;
                if (aclick == "Type2Selected") type2.Checked = true;
                if (aclick == "Type3Selected") type3.Checked = true;
                if (aclick == "Type4Selected") type4.Checked = true;
LVL 1
minglelinchAsked:
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asp_net2Commented:
Can you please be more specific on what you are trying to accomplish?
minglelinchAuthor Commented:
There are only four radio buttons initially on a page with none of them selected.
When a user selects one of the four buttons, the corresponding panels/divs/fields will be displayed below the radiobutton group. The MakeSwitch server function will do this work.

private void MakeSwitch()
    {
        if (type1.Checked == true)
        {
            type1panel.Attributes.Add("style", "display:inline");
            type1fields.Attributes.Add("style", "display:inline");
            ... ...
            type4fields.Attributes.Add("style", "display:none");
            type4buttons.Attributes.Add("style", "display:none");
        }
        if (type2.Checked == true)
        {
            type2panel.Attributes.Add("style", "display:inline");
            type2fields.Attributes.Add("style", "display:inline");
            ... ...
            type4fields.Attributes.Add("style", "display:none");
            type4buttons.Attributes.Add("style", "display:none");
            LoadType2SoemCombList(ref ddltylist);
        }
        ... ...    
    }

When the user click a different radio button, the previous panels would be hidden and new panels would show. This is why  a confirm box pops up.

If the user choose OK of the confirm box, the corresponding panels/fields of the selected button will be displayed.

If the user choose Cancel of the confirm box, the page would keep same with the selected radio button prior to the clicking being recovered to be selected. Because when the code execution goes into the DevSelected function, the newly clicked button has already been selected, and this is why a session variable is used to store the selected button prior to the clicking. Since the previous selected button is memorized, once Cancel of the confirm box is chosen, the button selection is resotred back by the code if (aclick == "Type1Selected") type1.Checked = true; ... ...

Now it seems the following code does not work. The page/fields keep same as expected except the radio button is not resotred. why? Thanks.

                if (aclick == "Type1Selected") type1.Checked = true;
                if (aclick == "Type2Selected") type2.Checked = true;
                if (aclick == "Type3Selected") type3.Checked = true;
                if (aclick == "Type4Selected") type4.Checked = true;
Alfred A.Commented:
Try the following.  I modified your code at the point of recovering your previous selected button.  I believe your problem is due to ambiguity in the true or false selection.  There can only be one true at any point in time with a group of radiobuttons.  
protected void DevSelected(object sender, System.EventArgs e)
{
        string aclick = (string)Session["TypeSelected"];
       
        if (aclick == "NoneSelected")    //Handles the initial click
        {
            MakeSwitch();
            if (type1.Checked)  aclick = "Type1Selected";
            if (type2.Checked)  aclick = "Type2Selected";
            if (type3.Checked)  aclick = "Type3Selected";
            if (type4.Checked)  aclick = "Type4Selected";
            Session.Add("TypeSelected", aclick);
        }
        else if (aclick != "NoneSelected")   //Handles the clicks after the initial clicking
        {
            if (MessageBox.Show("would you want to make a switch and ignore these data?", "Confirm Switch", MessageBoxButtons.YesNo) == DialogResult.Yes)
            {
                MakeSwitch();
            }
            else
            {
                //Recover the previous selected button selection if No/Cancel of the confirm box is chosen.
                if (aclick == "Type1Selected") { type1.Checked = true; type2.Checked = false; type3.Checked = false; type4.Checked = false; }
                if (aclick == "Type2Selected") { type1.Checked = false; type2.Checked = true; type3.Checked = false; type4.Checked = false; }
                if (aclick == "Type3Selected") { type1.Checked = false; type2.Checked = false; type3.Checked = true; type4.Checked = false; }
                if (aclick == "Type4Selected") { type1.Checked = false; type2.Checked = false; type3.Checked = false; type4.Checked = true; }
            }
        }
    }

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minglelinchAuthor Commented:
Thanks. Great answer on the server side.
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