Wince SQLce 数据库连接的怪事

e_zhiwen 2012-09-02 07:15:18

先看代码：



DB d = new DB();

            

            //string sql = "Select BarcodeType,BarcodeContext From BarcodeTable Where Barcode='"+textBox1.Text.Trim()+"'";

           string sql="Select Barcode,Barcodetype,barcodecontext from barcodetable where barcode like '%"+textBox1.Text.Trim()+"%'";

           // string sql = "Select Barcode,Barcodetype,barcodecontext from barcodetable";

            DataTable dt1 = new DataTable();

            dt1 = d.SelectContext(sql);

            dataGrid1.DataSource = dt1;

带条件的无法取到数据，不带条件的可以取到数据.有点不太清楚为什么？

//再次修改过了条件，用模拟的又可以出结果。为什么呢？



 public DataTable SelectContext(string sql)

        {

            SqlCeConnection conn=opensqlce();

            DataTable dt = new DataTable();

            DataSet ds = new DataSet();

            try

            {



                SqlCeCommand cmd = new SqlCeCommand(sql, conn);

                SqlCeDataAdapter da = new SqlCeDataAdapter(cmd);



                da.Fill(ds);

                dt = ds.Tables[0];

               

            }

            catch (Exception ex)

            {

                MessageBox.Show(ex.Message);

            }

            finally

            {

                conn.Close();

            }

            return dt;

           





        }

        private SqlCeConnection opensqlce()

        {

            string ceConnStr = @"Data Source ="+System.IO.Path.GetDirectoryName(System.Reflection.Assembly.GetExecutingAssembly().GetName().CodeBase)+"\\TPM.sdf";

            SqlCeEngine engine = new SqlCeEngine(ceConnStr);

            SqlCeConnection connMobile = new SqlCeConnection(ceConnStr);

            try

            {

                connMobile.Open();

            }

            catch (Exception ex)

            {

                MessageBox.Show("不能连接数据库!" + ex.Message);

                return null;

            }

            return connMobile;

        }