“Some of the properties for this Web Part cannot be set or displayed properly”

Question

Im getting this error when trying to add a custome property to a webpart, what have I done wrong?

    [WebBrowsable(true),
    Personalizable(true),
    WebDisplayName("Site Root"),
    WebDescription("blah blah"),
    Category("Custome Settings"),
    WebPartStorage(Storage.Shared)]
    public string SiteRoot
    {
        set { HttpContext.Current.Session["SiteRoot"] = value; }
    }

(Image of error is here, cant put it the question as new users cant use the image tag!?! wtf?)

http://www.freeimagehosting.net/uploads/d1bdd5989c.png

Answer 1

A web part property is used to bind configuration settings to and from the web part settings database.

Your command:

set { HttpContext.Current.Session["SiteRoot"] = value; }

does not make sense to put in a property

It should be something like this

private string _siteroot;
[WebBrowsable(true),
    Personalizable(true),
    WebDisplayName("Site Root"),
    WebDescription("blah blah"),
    Category("Custome Settings"),
    WebPartStorage(Storage.Shared)]
public string SiteRoot {
    get { return _siteroot; }
    set { _siteroot = value; }
}

And then you can use the property like this

protected override void OnLoad(EventArgs e) {
    base.OnLoad(e);

    if(!IsPostBack) {
        HttpContext.Current.Session["SiteRoot"] = SiteRoot;
    }
}

Answer 2

See this post. It shows creating a custom property, and accessing that property from the code behind of your user control.