יש לי שגיאה בהרצת קוד בWINFORM

the type name 'OleDbConnection' could not be found in the namespacw 'System.Data.OleDb'. This type has been forwarded

זו השגיאה שכתובה לי.

כל ה oleDb מסומנים באדום

יש לציין שיש לי using System.Data.OleDb

אשמח לתשובה.

תודה מראש😘

מצורף כל הקוד של class Dal

using System;

using System.Collections.Generic;

using System.ComponentModel;

using System.Data;

using System.Data.OleDb;

using System.Drawing;

using System.Linq;

using System.Text;

using System.Threading.Tasks;

using System.Windows.Forms;

namespace WinFormsApp1.DAL

{

public class ClassDal

{

private DataSet ds;

private OleDbConnection con;

public ClassDal()

{

ds = new DataSet();

con = new OleDbConnection("Provider=Microsoft.Jet.OLEDB.4.0;Data Source=" + Application.StartupPath + @"\project_shira_b.mdb");

}

public void AddTable(string tableName)

{

OleDbDataAdapter adapter = new OleDbDataAdapter("select * from " + tableName, con);

if (!ds.Tables.Contains(tableName))

adapter.Fill(ds, tableName);

}

public DataTable GetTabel(string tableName)

{

if (!ds.Tables.Contains(tableName))

AddTable(tableName);

return ds.Tables[tableName];

}

public DataTable GetQuery(string sqlString)

{

OleDbDataAdapter adapter = new OleDbDataAdapter(sqlString, con);

DataTable table = new DataTable();

adapter.Fill(table);

return table;

}

public void UpDate(string tableName)

{

OleDbDataAdapter adapter = new OleDbDataAdapter("select * from " + tableName, con);

OleDbCommandBuilder builder = new OleDbCommandBuilder(adapter);

adapter.InsertCommand = builder.GetInsertCommand();

adapter.DeleteCommand = builder.GetDeleteCommand();

adapter.UpdateCommand = builder.GetUpdateCommand();

adapter.Update(ds, tableName);

}

}

}