Mismatched datatype on access the type is ShortText?

System.Data.OleDb.OleDbException: 'Data type mismatch in criteria expression.'
 
code sample

public void search()
{
string search = Convert.ToString(txtSearch.Text);
con = new ConnectionClass();
con.oledbquery("select * from tableuser where primarykey = " +search+" ") ;
con.d2 = con.cmd.ExecuteReader();
// con.queryex();
while (con.d2.Read())
{
weredaId_47.Text = con.d2[0].ToString();
regBookNo_1.Text = con.d2.GetString(1);
birthRegBookNo_2.Text = con.d2.GetString(2);
regOfficeNo_3.Text = con.d2.GetString(3);
birthRegIdNo_4.Text = con.d2.G
 }
} 

Try to get the select query from C# watch window and run it against ACCESS database to check the issue.