Smalldatetime To String Conversion, Can't Find Error

Hi, I'm making a webapplication in C# with MSSQL as database.

I've created a form to do an advanced search on books. The user can type in name, author, .... and he can also mark 2 dates from to Calendar objects (I made sure date one can not be bigger than date 2). I'm using smalldatetime as DBtype. The 2 selected values are DateTime in asp. The results are shown in a gridview. Since I added the feature I keep getting the same error and I can't find where it is. Here's some code:

 1 public List GetBooks2(string invB,string titelB, string auteursB, string taalB, string uitgeverijB, string jaarB, string keywordsB, string categorieB, string standplaatsB, string ISBN,DateTime datum1, DateTime datum2, string sortExpression)
2 { //this is my method for the advanced search
3 using (SqlConnection oConn = new SqlConnection(_connectionString))
4 {
5 string strSql = "select * FROM Boek where 1 = 1";
6 if (!String.IsNullOrEmpty(invB)) strSql += " and (inventaris_nr like @invB)";
7 if (!String.IsNullOrEmpty(titelB)) strSql += " and (titel like @titelB)";
8 if (!String.IsNullOrEmpty(auteursB)) strSql += " and (auteurs like @auteursB)";
9 if (!String.IsNullOrEmpty(uitgeverijB)) strSql += " and (uitgeverij like @uitgeverijB)";
10 if (!String.IsNullOrEmpty(ISBN)) strSql += " and (ISBN10 like @ISBN or ISBN13 like @ISBN)";
11 if (!String.IsNullOrEmpty(standplaatsB)) strSql += " and (standplaats like @standplaatsB)";
12 if (!String.IsNullOrEmpty(jaarB)) strSql += " and (jaartal like @jaarB)";
13 if (!String.IsNullOrEmpty(keywordsB)) strSql += " and (keywords like @keywordsB)";
14 if (!String.IsNullOrEmpty(taalB))
15 if (taalB == "Andere")
16 strSql += " and (taal NOT IN ('nederlands', 'frans', 'engels', 'spaans', 'italiaans', 'duits'))";
17 if (taalB == "--Geen voorkeur--")
18 strSql += "";
19 else
20 strSql += " and (taal like @taalB)";
21
22 if (!String.IsNullOrEmpty(categorieB))
23 if (categorieB == "--Selecteer een categorie--")
24 strSql += "";
25 else
26 strSql += " and (categorie like @categorieB)";
27
28 if (datum1 == null)
29 strSql += "";
30 else
31 if (datum2 != null)
32 {
33
34 strSql+=" and datumB between @datum1 and @datum2";
35 }
36 else strSql+="";
37 if (!String.IsNullOrEmpty(sortBLOCKED EXPRESSION
38 strSql += " order by " + sortExpression;
39 else
40 strSql += " order by id";
41
42 SqlCommand oCmd = new SqlCommand(strSql, oConn);
43 oCmd.Parameters.Add(new SqlParameter("@invB", "%" + invB + "%"));
44 oCmd.Parameters.Add(new SqlParameter("@titelB", "%" + titelB + "%"));
45 oCmd.Parameters.Add(new SqlParameter("@auteursB", "%" + auteursB + "%"));
46 oCmd.Parameters.Add(new SqlParameter("@taalB", "%" + taalB + "%"));
47 oCmd.Parameters.Add(new SqlParameter("@uitgeverijB", "%" + uitgeverijB + "%"));
48 oCmd.Parameters.Add(new SqlParameter("@jaarB", "%" + jaarB + "%"));
49 oCmd.Parameters.Add(new SqlParameter("@keywordsB", "%" + keywordsB + "%"));
50 oCmd.Parameters.Add(new SqlParameter("@categorieB", categorieB ));
51 oCmd.Parameters.Add(new SqlParameter("@standplaatsB", "%" + standplaatsB + "%"));
52 oCmd.Parameters.Add(new SqlParameter("@ISBN", "%" + ISBN + "%"));
53 oCmd.Parameters.Add(new SqlParameter("@datum1", "%" + datum1 + "%"));
54 oCmd.Parameters.Add(new SqlParameter("@datum2", "%" + datum2 + "%"));
55
56
57 oConn.Open();
58 SqlDataReader oReader = oCmd.ExecuteReader();
59 List boeken = GetBoekCollectionFromReader(oReader);
60 oReader.Close();
61 return boeken;
62 }
63 }


 

I think that that method is correct, not sure though...  The code for GetBoekCollectionFromReader(oReader) is this=1 protected List GetBoekCollectionFromReader(IDataReader oReader)
2 {
3 List boeken= new List();
4 while (oReader.Read()) //THIS IS WHERE THE ERROR APPEARS
5 {
6 boeken.Add(GetBoekFromReader(oReader));
7
8 }
9 return boeken;
10 }
  

 

That's the method where the error appears... Where should I place a breakpoint to get the exact location? To make sure all methods in this code are explained, here's the code for GetBoekFromReader(oReader))= 1 protected Boek GetBoekFromReader(IDataRecord oReader)
2 {
3 Boek boek = new Boek();
4 boek.idB= (int)oReader["id"];//id auto generated dus verplicht
5 if(oReader["inventaris_nr"] != DBNull.Value)
6 boek.Inventaris_nrB = (string)oReader["inventaris_nr"];
7 if (oReader["auteurs"] != DBNull.Value)
8 boek.AuteursB = (string)oReader["auteurs"];
9 boek.TitelB = (string)oReader["titel"];//titel verplicht
10 if (oReader["taal"] != DBNull.Value)
11 boek.TaalB = (string)oReader["taal"];
12 if (oReader["uitgeverij"] != DBNull.Value)
13 boek.UitgeverijB = (string)oReader["uitgeverij"];
14 if (oReader["aantal_p"] != DBNull.Value)
15 boek.Aantal_pB = (string)oReader["aantal_p"];
16 if (oReader["jaartal"] != DBNull.Value)
17 boek.JaartalB = (int)oReader["jaartal"];
18 if (oReader["keywords"] != DBNull.Value)
19 boek.KeywordsB = (string)oReader["keywords"];
20 if (oReader["categorie"] != DBNull.Value)
21 boek.CategorieB = (string)oReader["categorie"];
22 if (oReader["standplaats"] != DBNull.Value)
23 boek.StandplaatsB = (string)oReader["standplaats"];
24 if (oReader["ISBN13"] != DBNull.Value)
25 boek.ISBN13 = (string)oReader["ISBN13"];
26 if (oReader["ISBN10"] != DBNull.Value)
27 boek.ISBN10 = (string)oReader["ISBN10"];
28 if (oReader["URL"] != DBNull.Value)
29 boek.UrlB = (string)oReader["URL"];
30 if (oReader["username"] != DBNull.Value)
31 boek.UsernameB = (string)oReader["username"];
32 if (oReader["passwoord"] != DBNull.Value)
33 boek.PasswoordB = (string)oReader["passwoord"];
34 if (oReader["datumB"] != DBNull.Value)
35 boek.DatumBoek = (DateTime)oReader["datumB"];
36 if (oReader["status"] != DBNull.Value)
37 boek.StatusB = (string)oReader["status"];
38
39
40 return boek;
41 }
  

Conversion failed when converting datetime from character string.

That's the error I get by the way. It also appears when I do a search and I don't use the date function... for example when I only fill in the title textbox and I don't select any dates from the calendars...

Sorry for the long post, but I think it's the only way to get a clear view on it...