Read unknown data from oledbdatareader?

Martin

HI,
If I use this code below
command = new OleDbCommand(SQLQUERY, myconn)
myReader = command.ExecuteReader();
while (myReader.Read())
{
while (i < myReader.FieldCount)
   {
      value = value + myReader.GetString(i) + "\t ";
      i++;
   }
listBox1.Items.Add(value);
value = "";
i = 0;
}
Then all the data must be of string value, Is there a option to check the type of value the next value is or must i know this?

2 Replies

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Sam Hobbs16y ago

For most data types you can just use ToString(). The following console program works with the Northwind sample data. This code uses SQL instead of OLEDB but you can just change Sql to OleDb.

using System;

using System.Collections.Generic;

using System.Linq;

using System.Text;

using System.Data.SqlClient;



namespace _80183

{

	class Program

	{

		static void Main(string[] args)

		{

			const String Query = "Select * From Territories";

			SqlConnection Connection;

			SqlCommand command;

			SqlDataReader myReader = null;

			try

			{

				Connection = new SqlConnection(

					Properties.Settings.Default.NORTHWND_ConnectionString);

				Connection.Open();

				command = new SqlCommand(Query, Connection);

				myReader = command.ExecuteReader();

			}

			catch (Exception ex)

			{

				Console.WriteLine(ex.ToString());

				return;

			}

			Object[] ca = new Object[myReader.FieldCount];

			String s;

			while (myReader.Read())

			{

				myReader.GetValues(ca);

				s = "";

				foreach (object o in ca)

				{

					s = s + o.ToString() + "\t ";

				}

				Console.WriteLine(s);

			}

		}

	}

}

Bryian Tan16y ago
hello,

You can do something like myReader.GetValue(i).GetType().ToString() to print out the type name
or

if (myReader.GetValue(i).GetType() == typeof(DBNull))
   Response.Write("null value");
else if (myReader.GetValue(i).GetType() == typeof(int32))
   value = value + myReader.GetInt32(i) + "\t ";
else if (myReader.GetValue(i).GetType() == typeof(String))
   value = value + myReader.GetString(i) + "\t ";
...
...

or, I think you can use

value = value + myReader.GetValue(i) + "\t ";

Thanks,
Bryian Tan