After few search in the database the search get slower

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MS-Access

C#5.0

Heloo,

A have a program with Microsoft access as database.

On first run if i do a search in my database, the result are returned very fast, but in time after multiple search, the search in slower, and slower.

This is my database class connection:

class MyAccessConnection : DataConnection
    {
        OleDbConnection Connection;
        OleDbCommand Command;
        OleDbTransaction OperatieDate;
        
        string ConnectionString = "Provider=Microsoft.Jet.OLEDB.4.0;Data Source=" + DataSource + ";Persist Security Info=True;Jet OLEDB:Database Password=" + Password + ";";
        public MyAccessConnection()
        {
            (Command = new OleDbCommand()).Connection = Connection = new OleDbConnection(ConnectionString);
            ConnectionDistructor = new System.Timers.Timer(60000);
            GC.KeepAlive(ConnectionDistructor);
        }

        public override void InceputTranzactie()
        {
            OperatieDate = Connection.BeginTransaction(IsolationLevel.ReadCommitted);
            Command.Connection = Connection;
            Command.Transaction = OperatieDate;
        }
        public override void CommitTranzaction()
        {
            OperatieDate.Commit();
        }
        public override void RollBackTranzaction()
        {
            OperatieDate.Rollback();
        }
        public override void FillDataTable(DataTable Table, bool Decrypt)
        {
            ConnectionDistructor.Enabled = false;
            if (Connection.State == System.Data.ConnectionState.Closed) Connection.Open();
            Status.Text = "1";
            try
            {
                Table.Rows.Clear();
                Table.Columns.Clear();
                new OleDbDataAdapter(Command).Fill(Table);
                //Table.Rows[1].ItemArray;

                int StartIndex = 1;
                try
                {
                    if (Table.Rows.Count > 0)
                        Table.Rows[0][0].ToString();
                    if (Table.Rows.Count > 1)
                        Table.Rows[1][0].ToString();
                }
                catch { StartIndex++; }
                for (int i = StartIndex; i < Table.Columns.Count; i++) for (int j = 0; j < Table.Rows.Count; j++)
                        Table.Rows[j][i] = Table.Rows[j][i].ToString();

            }
            catch (Exception Ex) {
                string msg = "Cod eroare: 001. \n\nEroare: \n" + Ex.Message;
                DoHandleException(msg);
            }
            finally { Command.Parameters.Clear(); ConnectionDistructor.Enabled = true; }
        }

        public override object ExecuteNonQuery()
        {
            ConnectionDistructor.Enabled = false;
            if (Connection.State == System.Data.ConnectionState.Closed) Connection.Open();
            Status.Text = "1";
            try
            {
                return Command.ExecuteNonQuery();
            }
            catch (Exception Ex) { throw Ex; }
            finally { Command.Parameters.Clear(); ConnectionDistructor.Enabled = true;  }
        }

        public override string CommandText
        {
            set
            {
                Command.CommandText = value;
            }
        }

        public override void AddParameter(string Name, object Value)
        {
            AddParameter(Name, Value, true);
        }

        public override void AddParameter(string Name, object Value, bool Encrypt)
        {
            Command.Parameters.Add(new OleDbParameter(Name, Value));
        }

        public override void Open()
        {
            Connection.Open();
        }

        public override void Close()
        {
            Connection.Close();
        }
}

And my search code:

private void CautareContractClick(object sender, EventArgs e)
        {
            int NumarContractCautat;
            if (int.TryParse(this.txtCautaContract.Text, out NumarContractCautat))
            {
                Contract contract = InterogariDB.IncarcaContract(NumarContractCautat);
                if (contract == null)
                {
                    MessageBox.Show(this, string.Format("Contractul {0} nu a fost gasit.", NumarContractCautat), "Cautare", MessageBoxButtons.OK, MessageBoxIcon.Exclamation);
                }
                else
                {
                    btnContractNou.Visible = true;
                    btnModifica.Visible = true;
                    grDateClient.Visible = true;
                    IncarcaClienti(" WHERE ClientID=" + contract.ClientId.ToString() + "", false);

                   
                    int rowIndex = -1;
                    foreach (DataGridViewRow row in dvContracteActive.Rows)
                    {
                        if (row.Cells[0].Value.ToString().Equals(contract.ContractId.ToString()))
                        {
                            rowIndex = row.Index;
                            dvContracteActive.FirstDisplayedScrollingRowIndex = rowIndex;
                            tabContracte.SelectedTab = contracteActive;
                            dvContracteActive.Rows[rowIndex].Selected = true;
                            break;
                        }
                    }

                    foreach (DataGridViewRow row in dvContracteInchise.Rows)
                    {
                        if (row.Cells[0].Value.ToString().Equals(contract.ContractId.ToString()))
                        {
                            rowIndex = row.Index;
                            dvContracteInchise.FirstDisplayedScrollingRowIndex = rowIndex;
                            tabContracte.SelectedTab = contracteIncheiate;
                            dvContracteInchise.Rows[rowIndex].Selected = true;
                            break;
                        }
                    }
                }
            }
        }

internal static Contract IncarcaContract(int contractId)
        {
            Program.Connection.CommandText = "select * from Contracts where ContractId=@ContractId";
            Program.Connection.AddParameter("@ContractId", contractId);
            DataTable Table = new DataTable();
            Program.Connection.FillDataTable(Table, true);
            if (Table.Rows.Count == 0)
            {
                throw new Exception(string.Format("Contractul {0} nu a fost gasit.", contractId));
            }
            return new Contract(Table);
        }

Where i need to look, haw to make my search from my program to work at the same speed.