Save a setting using

ModuleController objModules = new ModuleController();
objModules.UpdateTabModuleSetting(TabModuleId, "controlToDisplay", DropDownList1.SelectedValue);

The value could be an int then put your controls in a multiview control and set the selectedviewindex to which ever part of the multiview you want to display.  Or use some if statements to decide from your settings value which controls you want to make visible and which invisible.

Ok, I found the solution for the previous issue: Instead of adding two definitions (one with a view and one with a edit control), I had to add only one definition and there add two Module Controls (one view and one edit control).

Anyways now I am facing the following issue: Although my code seems to be correct, everytime I load the page with the module the same first view appears instead of that one picked by the dropdown in the module settings. My code:

In settings.ascx.cs:

public partial class Settings : DotNetNuke.Entities.Modules.ModuleSettingsBase
{
    public override void LoadSettings() {
        try
        {
            if ((Page.IsPostBack == false))
            {
                if ((TabModuleSettings["employeesql_selectedview"]) == null)
                {
                    TabModuleSettings["employeesql_selectedview"] = 0;
                }
                ddnViewSelector.SelectedIndex = Convert.ToInt32(TabModuleSettings["employeesql_selectedview"]);
            }
        }
        catch (Exception exc)
        {
            Exceptions.ProcessModuleLoadException(this, exc);
        }
    }

    public override void UpdateSettings()
    {
        try
        {
            DotNetNuke.Entities.Modules.ModuleController objModules = new DotNetNuke.Entities.Modules.ModuleController();
            objModules.UpdateTabModuleSetting(ModuleId, "employeesql_selectedview", Convert.ToString(ddnViewSelector.SelectedIndex));
        }
        catch (Exception exc)
        {
            Exceptions.ProcessModuleLoadException(this, exc);
        }
    }
}
 

In view.ascx.cs:

protected void Page_Load(object sender, System.EventArgs e)
    {
        if (Page.IsPostBack)
        {
        }
        else
            {      
                ModuleController objModules = new ModuleController();
                int goTo = System.Convert.ToInt32(objModules.GetTabModuleSettings(TabModuleId)["employeesql_selectedview"]);
               
                switch (goTo) {
                    case 0: employeeSQLViews.ActiveViewIndex = 0; break;
                    case 1: employeeSQLViews.ActiveViewIndex = 1; break;
                    case 2: employeeSQLViews.ActiveViewIndex = 0; break;
                    case 3: employeeSQLViews.ActiveViewIndex = 4; break;
                    case 4: employeeSQLViews.ActiveViewIndex = 2; break;
                    case 5: employeeSQLViews.ActiveViewIndex = 3; break;
                    default: employeeSQLViews.ActiveViewIndex = 0; break;
                }
               
            }
    }