Retaining enum values in asp.net

Question

I have an asp.net page, wherein i am using enums (with Properties defined in class file in app_code)

Now my problem is whenever page gets postbacks the value of the enum in property gets resetted to the first one

I even tried setting the property as static, but still that didn't helped.

below is

my enum and property declaration:

private static UrlType _type;
public static UrlType UrlPattern
{
    get
    {
        HttpContext.Current.Response.Write("GET: " +_type + "<br>");
        return _type;
    }
    set
    {
        _type = value;
        HttpContext.Current.Response.Write("SET : " +_type + "<br>");
    }
}
public int VanityId { get; set; }
public enum UrlType
{
    ArticleOnly,
    ArticleCategoryCombination,
    Normal,
    TechForum
}

and this is how i calls:

public void BindRewrite()
{
    GrdRewrite.DataSource = objVanity.GetAllRewriteVanities(Vanity.UrlPattern);
    GrdRewrite.DataBind();
    if (Vanity.UrlPattern == Vanity.UrlType.ArticleCategoryCombination)
    {
        GrdRewrite.Columns[2].Visible = false;
        GrdRewrite.Columns[3].Visible = GrdRewrite.Columns[5].Visible = GrdRewrite.Columns[6].Visible = true;
    }
    else if (Vanity.UrlPattern == Vanity.UrlType.ArticleOnly)
    {
        GrdRewrite.Columns[5].Visible = true;
        GrdRewrite.Columns[2].Visible = GrdRewrite.Columns[3].Visible = GrdRewrite.Columns[6].Visible = false;
    }
    else if (Vanity.UrlPattern == Vanity.UrlType.Normal)
    {
        GrdRewrite.Columns[2].Visible = true;
        GrdRewrite.Columns[3].Visible = GrdRewrite.Columns[5].Visible = GrdRewrite.Columns[6].Visible = false;
    }
}

protected void Page_Load(object sender, EventArgs e)
{
    pnlAdmin.Visible = (objVanity.UserName == "host");

    if (objVanity.UserName == "host")
        Enable();
    else
        FieldsOpenForEditors(objVanity.SiteSupportUrlFormat);

    if (!IsPostBack)
    {
        Vanity.GenerateListFromEnums(drpAdminUrlType);
        if (objVanity.UserName == "host")
            Vanity.UrlPattern = Vanity.UrlType.ArticleOnly;
        else
            Vanity.UrlPattern = objVanity.SiteSupportUrlFormat;

        BindRewrite();
    }
}

can anyone tell me how to retain the value of the enum across postbacks

i think viewstate could be option, but don't have any clue about how to store the enum value and restore the string value casted in enum.

Answer 1

If you want to persist a value between post back, you need to store it in Session, Cache or ViewState.

In your case, ViewState could be a prefer choice.

public UrlType UrlPattern
{
    get
    {
        if (ViewState["UrlPattern"] != null)
            return (UrlType)Enum.Parse(typeof(UrlType), ViewState["UrlPattern"].ToString());
        return UrlType.Normal; // Default value
    }
    set
    {
        ViewState["UrlPattern"] = value;
    }
}