get data form local database(.sdf)

Question

0.00/5 (No votes)

See more:

I'm using a C# Windows form application
My program store data in local database (.sdf). I can't get data from the database.
No errors but no retrieving data from database
this my code this is my first local database program
what is the wrong ?
Is there any other way to do this ?

table name = tbl_user
column name = u_name

C#

SqlCeConnection con = new SqlCeConnection("Data Source=H:\\application\\database.sdf");
            try
            {
                SqlCeCommand com = new SqlCeCommand("SELECT * FROM tbl_user WHERE u_id=@u_id", con);
                com.Parameters.AddWithValue("u_id", 1);
                SqlCeDataReader reader = com.ExecuteReader();
                string name = reader["u_name"].ToString();
                MessageBox.Show(name);
                con.Close();
            }
            catch (SqlCeException)
            {
                MessageBox.Show("Error");
               
            }

Thank in Advance!

Posted 22-Oct-13 20:22pm

Manoj Chamikara

Updated 22-Oct-13 21:17pm

v2

Add a Solution

Comments

sp_suresh 23-Oct-13 2:32am

what is .sdf?which type database?

Manoj Chamikara 23-Oct-13 2:35am

@spshewale local database SQL server compact edition , file extension (.sdf)

2 solutions

Add a Solution

Add your solution here

Treat my content as plain text, not as HTML

Preview 0

…

Existing Members

Sign in to your account

...or Join us

Download, Vote, Comment, Publish.

Your Email
Password
Forgot your password?

Your Email
This email is in use. Do you need your password?
Optional Password

I have read and agree to the Terms of Service and Privacy Policy
Please subscribe me to the CodeProject newsletters

When answering a question please:

Read the question carefully.
Understand that English isn't everyone's first language so be lenient of bad spelling and grammar.
If a question is poorly phrased then either ask for clarification, ignore it, or edit the question and fix the problem. Insults are not welcome.
Don't tell someone to read the manual. Chances are they have and don't get it. Provide an answer or move on to the next question.

Let's work to help developers, not make them feel stupid.

This content, along with any associated source code and files, is licensed under The Code Project Open License (CPOL)

phil.o · Answer 1 · 2013-10-22T21:06:00

Solution 1

You should start by replacing

C#

SqlCeConnection con = new SqlCeConnection("Data Source="H:\application\database.sdf"");

with

C#

SqlCeConnection con = new SqlCeConnection("Data Source=""H:\\application\\database.sdf""");

and see if it changes something.

Quotes in a string have to be doubled or escaped ; and it is the same with backslashes.

You can find the reference here:
String literals[^]

[edit]

You do not seem to ever open your connection ; that can be the problem, also.
A better way to handle that would certainly be:

C#

using (SqlCeConnection con = new SqlCeConnection("Data Source=""H:\\application\\database.sdf""")) {
   try {
      con.Open();
      // ... rest of the code ...
   }
   catch (SqlCeException e) {
      MessageBox.Show(e.Message); // Would be an improvement than just the word 'Error'
   }
}

[/edit]

Posted 22-Oct-13 21:06pm

phil.o

Updated 22-Oct-13 21:22pm

v2

Comments

Manoj Chamikara 23-Oct-13 3:13am

Thank you phil I change the code but still the same thing
No error
No data retrieving
And update the question

phil.o 23-Oct-13 3:22am

Please see my updated answer ; you do not seem to ever open the connection.

Manoj Chamikara 23-Oct-13 3:36am

Thank you very much phil
I put a message box to find where the error message box 1 to 5 popup but message box 6 not pop up

MessageBox.Show("1");
using (SqlCeConnection con = new SqlCeConnection("Data Source=""H:\\application\\database.sdf"""))
try
{
MessageBox.Show("2");
con.Open();
MessageBox.Show("3");
SqlCeCommand com = new SqlCeCommand("SELECT * FROM tbl_user WHERE u_id=@u_id", con);
MessageBox.Show("4");
com.Parameters.AddWithValue("u_id", 1);
SqlCeDataReader reader = com.ExecuteReader();
MessageBox.Show("5");
string name = reader["u_name"].ToString();
MessageBox.Show("6");
MessageBox.Show(name);
con.Close();
}
catch (SqlCeException e)
{
MessageBox.Show(e.Message)
}

phil.o 23-Oct-13 3:39am

Please give up with these message boxes everywhere ; better put a breakpoint at the beginning of the method and hit F5 to enter debug mode ; the F11 to execute line by line, and check for your variables each time.

Manoj Chamikara 23-Oct-13 3:45am

Thank you phil appreciate your help

sp_suresh · Answer 2 · 2013-10-22T23:23:00

it seeems that reader is not fetching data
you should do like
string apppath = Application.StartupPath.ToString() + "\\Northwind.sdf";
SqlConnection con = new SqlConnection("Data Source=KTPL11\\SQLEXP_KTPL11;Initial Catalog=Trial;Integrated Security=true");

try
{
con.Open();
SqlCommand com = new SqlCommand("SELECT * FROM tbl_user WHERE u_id=1", con);
com.CommandType = CommandType.Text;
com.Parameters.AddWithValue("u_id", 1);
using (SqlDataReader reader = com.ExecuteReader())
{
string name = "";
if (reader.Read())
{
name = reader["u_name"].ToString();
}
MessageBox.Show(name);
}
con.Close();
}
catch (SqlException ex)
{
MessageBox.Show("Error");

}