How to create a connection file

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I am connecting to the database with the code below

string connString = @"Data source = test2 ; Database=test1data ; User Id=a ; Password=test1234";
   using (SqlConnection sqlConn = new SqlConnection(connString))
            {
                string sqlQuery = @"SELECT * from Zone";
                SqlCommand cmd = new SqlCommand(sqlQuery, sqlConn);
                SqlDataAdapter da = new SqlDataAdapter(cmd);
                DataTable table = new DataTable();
                da.Fill(table);
                dataGridView1.DataSource = new BindingSource(table, null);
            }

But I wanted to create a file to connect that could be changed.

For example:

I'm connecting to a database, but changing this file I'll connect to another database

What I have tried:

var connectionString = System.Configuration.ConfigurationManager.ConnectionStrings["test"].ConnectionString;
          // ConfigurationManager.ConnectionStrings["testdb"].ConnectionString;
           using (SqlConnection sqlConn = new SqlConnection(connectionString))
           {
               string sqlQuery = @"SELECT * from Zone";
               SqlCommand cmd = new SqlCommand(sqlQuery, sqlConn);
               SqlDataAdapter da = new SqlDataAdapter(cmd);
               DataTable table = new DataTable();
               da.Fill(table);
               dataGridView1.DataSource = new BindingSource(table, null);
           }

And this is the code i tryed in app.config

<add name="test" connectionString="Data Source=.;Initial Catalog=test1data; User Id=a ; Password=test123" providerName="System.Data.SqlClient" />

Posted 16-Aug-17 3:36am

PedroAzevedo1234

Updated 16-Aug-17 3:41am

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Karthik_Mahalingam 16-Aug-17 10:00am

so what is the issue

1 solution

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Graeme_Grant · Answer 1 · 2017-08-16T03:41:00

Solution 1

This will show you how: How to: Save and Edit Connection Strings[^]

Update: Here is a CodeProject article that show you how to do it in code: Saving Connection Strings to app.config[^]

Posted 16-Aug-17 3:41am

Graeme_Grant

Updated 16-Aug-17 4:01am

v2

Comments

PedroAzevedo1234 16-Aug-17 9:50am

That dont explain

Graeme_Grant 16-Aug-17 9:59am

Huh? It has step-by-step instructions on how to do it. You want me to write the code for you?

PedroAzevedo1234 16-Aug-17 10:10am

But it don´t help in my problem, when I run the progam it gives this error ConfigurationErrorsException: Connectionstrings Unknown configuration section

Dave Kreskowiak 16-Aug-17 10:12am

Without seeing the code you wrote to get the connection string from the config file and the content of the config file itself, it's pretty much impossible to tell you what you did wrong.

Dave Kreskowiak 16-Aug-17 10:13am

Connectionstrings Unknown configuration section

If this is really how you named the section in the config file, you've got it wrong. It should be "connectionStrings", not "Connectionstrings". CHARACTER CASE MATTERS!

PedroAzevedo1234 16-Aug-17 10:28am

The code I use is the what I have tried

Graeme_Grant 16-Aug-17 10:44am

Dave & I are trying to help you. Have another read of Dave's helpful guidance, and also read and try out the sample code in the article link above.

PedroAzevedo1234 16-Aug-17 10:48am

I only said that the code I used on my program is on "What I have tried"

Graeme_Grant 16-Aug-17 10:52am

Look at what works, then look at your code.

PedroAzevedo1234 16-Aug-17 11:00am

Sorry I can´t see where is the error on my code

Graeme_Grant 16-Aug-17 11:21am

Try:

var connectionString = System.Configuration.ConfigurationManager.ConnectionStrings["test"];

PedroAzevedo1234 16-Aug-17 11:37am

I am using this code to connect and now it says the "connectionString" can not be converted to a string

using (SqlConnection sqlConn = new SqlConnection(connectionString))
{
string sqlQuery = @"SELECT * from Zone";
SqlCommand cmd = new SqlCommand(sqlQuery, sqlConn);
SqlDataAdapter da = new SqlDataAdapter(cmd);
DataTable table = new DataTable();
da.Fill(table);
dataGridView1.DataSource = new BindingSource(table, null);
}

Graeme_Grant 16-Aug-17 11:40am

I tested the above fix and works. Set a debug breakpoint, step through the code, and inspect the values before they execute. The immediate window is also useful in break mode for testing values & code...

PedroAzevedo1234 16-Aug-17 11:42am

Can you write the code you used ? I dont see where I fail

Graeme_Grant 16-Aug-17 12:28pm

var connectionString = System.Configuration.ConfigurationManager.ConnectionStrings["test"];