如何在Ole Db连接中的文本框中指定文件路径名

Question

I am using the bellow code to import .csv file in to datagridview ..., i am getting an error ie g_03_04_2014.csv is not a valid path . ...

   private void timer2_Tick(object sender, EventArgs e)
   {


       string dt = DateTime.Now.ToString("hh.mm.ss.ffffff");
       string var1 = (dt);
       string var2 = adsClient.ReadAny(hActVel, typeof(double)).ToString(); ;
       string var3 = adsClient.ReadAny(hSActVel, typeof(double)).ToString(); ;
       StreamWriter sw = File.AppendText(NameYourFile.Text + "_" + DateTime.Today.ToString("MM_dd_yyyy") + ".csv");


       {

           if (BigMotorActualVelocity.Checked && SmallMotorActualVelocity.Checked)
           {
               sw.WriteLine(string.Format("{0},{1},{2}",var1, var2, var3));

           }

           else if (BigMotorActualVelocity.Checked)
           {
               sw.WriteLine(string.Format("{0},{1}",var1 , var2));
           }

           else if (SmallMotorActualVelocity.Checked)
           {
               sw.WriteLine(string.Format("{0},{1},{2}",var1," ",var3));
           }
           else
           {
               sw.WriteLine(string.Format("{0}",var1));
           }

           sw.Dispose();

       }


       string filepathName = NameYourFile.Text + "_" + DateTime.Now.ToString("MM_dd_yyyy") + ".csv";
       string sconn = "Provider=Microsoft.Jet.OLEDB.4.0;Data Source=" +
           filepathName + ";Extended Properties='text;HDR=Yes;FMT=Delimited(,)';";

       OleDbConnection connection = new OleDbConnection(sconn);

       OleDbCommand command = new OleDbCommand("Select * From ["+Path.GetFileName(filepathName) +"]",connection);

       DataSet ds = new DataSet();
       OleDbDataAdapter adapter = new OleDbDataAdapter(command);

       adapter.Fill(ds);
       dataGridView1.DataSource =  ds.Tables[0];

   }                                                                                     Thank you...  

Answer 1

File.AppendText method takes full path as a parameter, not the file name.

public static StreamWriter AppendText(
    string path
)

Parameters
Type: System.String
The path to the file to append to. 

g_03_04_2014.csv is just a file name, not path.

Answer 2

You will need to provide complete file path in the connection string for this. If you only provide name, application will look for the file in the same directory as the executable.

Answer 3

You are not setting up your connection string correctly.
When reading from a CSV file, your datasource is the directory where your file resides and the table is the file name

string fileName = NameYourFile.Text + "_" + DateTime.Now.ToString("MM_dd_yyyy") + ".csv";
string folderName = Application.StartupPath;  
string sconn = "Provider=Microsoft.Jet.OLEDB.4.0;Data Source=" +
       folderName + ";Extended Properties='text;HDR=Yes;FMT=Delimited(,)';";

OleDbCommand command = new OleDbCommand("Select * From ["+fileName+"]",connection);

Lacking better context, I have used the Application.StartupPath as the folder where you have saved the CSV file, however, I really suggest to change this location to a place better suited to store user data files and free from permission problems.

Use Environment.GetFolderPath(Environment.SpecialFolder.CommonApplicationData) as a base path for save and read then create your dedicated folder there where you store your files