سلام این کد می تونه کمکت کنه
try
{
string cnString = @"Data Source=.\SQLEXPRESS;AttachDbFilename=|DataDirector y|\SELLPC.mdf;Integrated Security=True;User Instance=True";
SqlConnection cn = new SqlConnection(cnString);
cn.Open();
SqlCommand com = new SqlCommand("SELECT * FROM TBLCPU WHERE MDLCPU LIKE '" +cmbmdlcpu. Text + "%'", cn);
SqlDataAdapter da = new SqlDataAdapter(com);
DataTable otabale = new DataTable();
da.Fill(otabale);
cn.Close();
txtprccpu.Text = otabale.Rows[0]["PRCCPU"].ToString();
txtvarrcpu.Text = otabale.Rows[0]["VARRCPU"].ToString();
}
catch (Exception EX)
{
MessageBox.Show(EX.Message);
}