creating a content type and attaching it to a Folder in Document Library and setting the metadata fields

public static void createCT(string Asset, SPFolder folder, SPList targetList)

{

SqlConnection cn = new SqlConnection("server=aaa;database=aaa;user id=sa;password=sa");

SqlCommand cmd = new SqlCommand("SELECT DISTINCT TBLATTLABEL.ATTLABELNAME, COMBINEDATTR.ATTRIBUTE, COMBINEDATTR.SEARCHVALUE, COMBINEDATTR.ISCI, COMBINEDATTR.IMAGEID, COMBINEDATTR.FORMATID FROM COMBINEDATTR INNER JOIN TBLATTLABEL ON TBLATTLABEL.ATTTABLESOURCE = 'Lookup_' + COMBINEDATTR.ATTRIBUTE WHERE ISCI ='" + Asset + "'AND IMAGEID = 0 ORDER BY ATTLABELNAME", cn);

cn.Open();

SqlDataReader dr = cmd.ExecuteReader();

using (SPSite p_site = new SPSite("http://localhost:10010/"))

{

using (SPWeb p_web = p_site.OpenWeb())

{

SPContentType CustomContentType = new

SPContentType(p_web.AvailableContentTypes["Folder"],

p_web.ContentTypes, Asset + "ContentType");

int i = 0;

while (dr.Read())

{

// A string Field

p_web.Fields.Add(dr[0].ToString(), SPFieldType.Text, false);

SPFieldLink fLink1 = new SPFieldLink(p_web.Fields[dr[i].ToString()]);

CustomContentType.FieldLinks.Add(fLink1);

}

p_web.ContentTypes.Add(CustomContentType);

CustomContentType.Update();

targetList.ContentTypes.Add(CustomContentType);

targetList.Update();

SPListItem item = folder.Item;

item["ContentTypeId"] = CustomContentType.Id;

item.Update();

dr.Close();

dr = cmd.ExecuteReader();

while (dr.Read())

{

item[dr[0].ToString()] = dr[2].ToString();

}

item.Update();

folder.Update();

}

}

}

an excellent MSDN article on content types