I have a database file that I beleive was created with Clipper but can't say for sure (I have .ntx files for indexes which I understand is what Clipper uses). I am trying to create a C# application that will read this database using the System.Data.OleDB namespace.
For the most part I can sucessfully read the contents of the tables there is one field that I cannot. This field called CTRLNUMS that is defined as a CHAR(750). I have read various articles found through Google searches that suggest field larger than 255 chars have to be read through a different process than the normal assignment to a string variable. So far I have not been successful in an approach that I have found.
The following is a sample code snippet I am using to read the table and includes two options I used to read the CTRLNUMS field. Both options resulted in 238 characters being returned even though there is 750 characters stored in the field.
Here is my connection string:
Provider=Microsoft.Jet.OLEDB.4.0;Data Source=c:\datadir;Extended Properties=DBASE IV;
Can anyone tell me the secret to reading larger fields from a DBF file?
using (OleDbConnection conn = new OleDbConnection(connectionString))
{
conn.Open();
using (OleDbCommand cmd = new OleDbCommand())
{
cmd.Connection = conn;
cmd.CommandType = CommandType.Text;
cmd.CommandText = string.Format("SELECT ITEM,CTRLNUMS FROM STUFF WHERE ITEM = '{0}'", stuffId);
using (OleDbDataReader dr = cmd.ExecuteReader())
{
if (dr.Read())
{
stuff.StuffId = dr["ITEM"].ToString();
// OPTION 1
string ctrlNums = dr["CTRLNUMS"].ToString();
// OPTION 2
char[] buffer = new char[750];
int index = 0;
int readSize = 5;
while (index < 750)
{
long charsRead = dr.GetChars(dr.GetOrdinal("CTRLNUMS"), index, buffer, index, readSize);
index += (int)charsRead;
if (charsRead < readSize)
{
break;
}
}
}
}
}
}