how to get tables of an access db into a list box using c#?

This class should get you the information you need.

public static class DatabaseInfoCollector
    {       
        public static System.Collections.Generic.List<string> GetTables(string file)
        {
            System.Data.DataTable tables;
            using(System.Data.OleDb.OleDbConnection connection = new System.Data.OleDb.OleDbConnection("Provider=Microsoft.Jet.OLEDB.4.0;Data Source=" + file))
            {
                connection.Open();
                tables = connection.GetOleDbSchemaTable(System.Data.OleDb.OleDbSchemaGuid.Tables,new object[]{null,null,null,"TABLE"});
            }
            System.Collections.Generic.List<string> Tables = new System.Collections.Generic.List<string>();
            for (int i = 0; i < tables.Rows.Count; i++)
            {
                Tables.Add(tables.Rows[i][2].ToString());
            }
            return Tables;
        }       

        public static System.Collections.Generic.List<string> GetColumnNames(string file, string table)
        {
            System.Data.DataTable dataSet = new System.Data.DataTable();            
            using(System.Data.OleDb.OleDbConnection connection = new System.Data.OleDb.OleDbConnection("Provider=Microsoft.Jet.OLEDB.4.0;Data Source=" + file))
            {
                connection.Open();
                System.Data.OleDb.OleDbCommand Command = new System.Data.OleDb.OleDbCommand("SELECT * FROM " + table,connection);
                using(System.Data.OleDb.OleDbDataAdapter dataAdapter = new System.Data.OleDb.OleDbDataAdapter(Command))
                {
                    dataAdapter.Fill(dataSet);
                }
            }
            System.Collections.Generic.List<string> columns = new System.Collections.Generic.List<string>();
            for(int i = 0; i < dataSet.Columns.Count; i ++)
            {
                columns.Add(dataSet.Columns[i].ColumnName);
            }
            return columns;
        }
    }

Fill the tables list like this.

System.Collections.Generic.List<string> Tables = DatabaseInfoCollector.GetTables(textBox1.Text);
foreach(string table in Tables)
{
     cboTable.Items.Add(table);
}

Fill the columns like this.

System.Collections.Generic.List<string> Columns = DatabaseInfoCollector.GetColumnNames(textBox1.Text,cboTable.SelectedItem.ToString());
foreach(string column in Columns)
{
     cboColumns.Items.Add(column);
}

You can also use this method to return a DataTable containing all kinds of information about each column.

public static System.Data.DataTable GetSchemaData(string file)
{
    System.Data.DataTable columns;
    using(System.Data.OleDb.OleDbConnection connection = new System.Data.OleDb.OleDbConnection("Provider=Microsoft.Jet.OLEDB.4.0;Data Source=" + file))
    {
        connection.Open();
        columns = connection.GetOleDbSchemaTable(System.Data.OleDb.OleDbSchemaGuid.Columns,new object[]{null,null,null,null});
    }
    return columns;
}

Use the System.Data.OleDb.* classes to get the data from the access file.

Example:

//Create the OleDbConnection object 
//and associate it with our database
using(OleDbConnection conn = new OleDbConnection(
    "PROVIDER=Microsoft.Jet.OLEDB.4.0;Data Source="+textBox1.Text)){

//Open the database connection
conn.Open();

//Create an OleDbCommand object and
//pass it the SQL read query and the connection to use
OleDbCommand cmd = new OleDbCommand(sqlstr,conn);

//Procure the OleDbDataReader object to browse the recordset 
OleDbDataReader rdr = cmd.ExecuteReader();

//Keep reading records in the forward direction
while (rdr.Read())
{
   //Use one of the various methods available to read the data
   //Eg:- GetValue, GetValues, Item etc.
. . .
. . .    
}

}

Use System.Data.OleDb to open a connection with new OleDbConnection(connectionString). The connection string should be "Provider=Microsoft.Jet.OLEDB.4.0;Data Source=[PathToMDBFile]"

var conn = new OleDbConnection(connectionString);
 var ds = new DataSet();
                var adapter = new OleDbDataAdapter("SELECT Column1 FROM Table1", conn);
                conn.Open();
                adapter.Fill(ds);
                conn.Close();
var value = ds.Tables[0].Rows[0]["Column1"].ToString();

That will get you the first value in the column named Column1