You should always set the Field property
scDateArticleDate.Field = StartDateFieldName // where is a string right!
Then you control the visibility of the item depending on if you have or not the item.
Also notice you post a image in your ascx and a date field in the .cs
the complete code would be
scDateArticleDate.Field = StartDateFieldName; //always set the field
if(currentItem != null)
{
Sitecore.Web.UI.WebControls.Date scDateArticleDate = e.Item.FindControl("scDateArticleDate") as Sitecore.Web.UI.WebControls.Date;
if (scDateArticleDate != null)
{
if (DisplayDates)
{
scDateArticleDate.Item = currentItem;
scDateArticleDate.Visible = true;
}
else
{
scDateArticleDate.Visible = false;
}
}
}
cheers