Accessing database connection string using app.config in C# winform

Question

I can't seem to be able to access the app.config database connection string in my c# winforms app.

app.config code

   <connectionStrings>
      <add name="MyDBConnectionString" providerName="System.Data.SqlClient"
            connectionString="Data Source=localhost;Initial Catalog=MySQLServerDB; Integrated Security=true" />
   </connectionStrings>  

C# code:

SqlConnection conn = new SqlConnection();
conn.ConnectionString = System.Configuration.ConfigurationSettings.AppSettings["MyDBConnectionString"];    

When I try the C# code, I get a message:
Warning 1 'System.Configuration.ConfigurationSettings.AppSettings' is obsolete: ' This method is obsolete, it has been replaced by System.Configuration!System.Configuration.ConfigurationManager.AppSettings'

However, when I try to use:

conn.ConnectionString = System.Configuration!System.Configuration.ConfigurationManager.AppSettings["MyDBConnectionString"];  

I get an error: Only assignment, call, increment, decrement, and new object expressions can be used as a statement

Pipistrelle

Usually I get that error when I don't put a () at the end of the line of code... (This is old, but I still like to comment) – Procora

Answer 1

This is all you need:

System.Configuration.ConfigurationManager.ConnectionStrings["MyDBConnectionString"].ConnectionString;

Bandaid

Answer 2

Use ConfigurationManager instead of ConfigurationSettings. It has a ConnectionStrings property that you should use for connection strings in the connectionStrings section:

ConfigurationManager.ConnectionStrings["MyDBConnectionString"].ConnectionString;

Inositol

Answer 3

You are using the ConnectionStrings collection, not the AppSettings.

ConfigurationManager.ConnectionStrings["MyDbConnectionString"].ConnectionString;

Newel

Answer 4

<?xml version="1.0" encoding="utf-8" ?>
<configuration>
  <appSettings>
    <add key="ConnectionString" value="Data Source=MY-PC;Initial Catalog=DB2013;User ID=sa;Password=MYSQL123" />
  </appSettings>
</configuration>

using System.Configuration;
using System.Data.SqlClient;

namespace OnlineDelete_W2013
{
    public partial class CommodityEdit : Form
    {
       SqlConnection MyConnection = new SqlConnection(System.Configuration.ConfigurationSettings.AppSettings["ConnectionString"]);
    
        public CommodityEdit()
        {
            InitializeComponent();
          
        }

        private void button1_Click(object sender, EventArgs e)
        {
            try
            {
               MyConnection.Open();
            }
            catch (Exception)
            {
                throw;
            }
        }
    }
}

Chopper

Answer 5

try this

 ConfigurationManager.ConnectionStrings["MyDbConnectionString"].ConnectionString; 

Supertanker

Answer 6

using (SqlConnection conn = new SqlConnection(System.Configuration.ConfigurationManager.ConnectionStrings["SQLConnection"].ToString()))
{
....(your code here) ...
}

Thermoplastic

Answer 7

SqlConnection conn = new SqlConnection();
conn.ConnectionString = ConfigurationManager
    .ConnectionStrings["MyDBConnectionString"].ConnectionString;
try
{
    conn.Open();                
}
catch (Exception)
{
    throw;                    
}

Teetotum

Answer 8

The answers stating to use the line

ConfigurationManager.ConnectionStrings["MyDBConnectionString"].ConnectionString;

are correct.

If an error appears stating that ConfigurationManager does not exist, it's because your project hasn't referenced System.Configuration.

To do that in .NET Framework, in Solution Explorer, in the project where you want to use this line of code, right-click in References, choose Add Reference..., then choose Assemblies on the left-side and Framework under it. Pick System.Configuration on the list and click Ok.

Gertudegerty

Answer 9

About this:

I get an error: Only assignment, call, increment, decrement, and new object expressions can be used as a statement

I just declared a var like this and solved the problem:

var strConnection = System.Configuration.ConfigurationManager.ConnectionStrings["MyDBConnectionString"].ConnectionString;

Detonate

Answer 10

Please try below code. this is as you are expecting:

SqlConnection MyConnection = new SqlConnection(ConfigurationManager.ConnectionStrings["ConnectionString"].ConnectionString);       

Undersexed