How to add and access connection string from web.config

Question

I want to add connection string to connect to mysql that are define in web.config file and access the same connection in my C# code how can I do this?

Here is my code sample that run after onclick of a button to connect to database.

protected void Button2_Click(object sender, EventArgs e)
    {
        String a = DropDownList1.SelectedItem.Value;
        String b = DropDownList3.SelectedItem.Value.PadLeft(3, '0');      
        String c = TextBox2.Text.PadLeft(5,'0').ToString();
        String d = TextBox3.Text.ToString();
        String digit = a+ b  + c + d;
        try
        {
         myConn = new OdbcConnection("Driver={MySQL ODBC 3.51 Driver};Server=localhost;Database=testcase;User=root;Password=root;Option=3;");
         myConn.Open();
            //**
            string sql = "select * from testcase.main where reg_no =?";            
            //**
            OdbcCommand cmd = new OdbcCommand(sql, myConn);            
            //**
            cmd.Parameters.AddWithValue("?", digit);
            MyReader = cmd.ExecuteReader();
            //**
            while (MyReader.Read())
            {
                String f = MyReader["pet_name"].ToString();
                String g = MyReader["res_name"].ToString();

                Label9.Visible = true;
                Label9.Text = f;

                Label10.Visible = true;
                Label10.Text = "VS";

                //Label11.Visible = true;
                Label11.Text = g;

            }

            MyReader.Close();
        }
        catch (Exception e1)
        {
            Response.Write(e1.ToString());
        }
        finally
        {
            if (MyReader != null && !MyReader.IsClosed)
            {
                MyReader.Close();   
            }

            if (myConn != null && myConn.State == ConnectionState.Open)
            {
                myConn.Close();
            }
        }

FYI it is bad practise to include this code in your presentation layer logic, consider refactoring so that your data layer is in seperate classes which you can call from your presentation (UI) layer. — Darbio
– Darbio, Commented Nov 18, 2010 at 5:39
can you please help me out with a small example,would be great if you show using my code — Ishan
– Ishan, Commented Nov 18, 2010 at 6:26
have a look at this question for some starters: stackoverflow.com/questions/304828/… — Darbio
– Darbio, Commented Nov 21, 2010 at 6:59

Darbio · Accepted Answer · 2010-11-18 05:38:11Z

3

If you know the connection string name you can use the ConnectionStrings property of the ConfigurationManager class

E.g.

using System.Configuration;
string ConnectionString = ConfigurationManager.ConnectionStrings["ConnectionStringName"].ConnectionString.ToString();

Where, your web.config would contain a connectionstring named ConnectionStringName

answered Nov 18, 2010 at 5:38

Darbio

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Comments

COLD TOLD · Accepted Answer · 2012-08-25 02:46:16Z

Here is an Example of Creating and adding connectionString to the web.config for SQL Server you can change the sql Connection to OleDb connection

SqlConnectionStringBuilder connectionStringBuilder = new SqlConnectionStringBuilder();
        connectionStringBuilder.DataSource = "localhost";
        connectionStringBuilder.IntegratedSecurity = true;
        connectionStringBuilder.InitialCatalog = "SampleDB";

        ConnectionStringSettings connSttng = new ConnectionStringSettings();
        connSttng.Name = "ConnectionStringName";
        connSttng.ProviderName = "Providername";
        connSttng.ConnectionString = String.Format("DataSource={0};InitialCatalog={1};IntegratedSecurity={2}", connectionStringBuilder.DataSource, connectionStringBuilder.InitialCatalog, connectionStringBuilder.IntegratedSecurity);

        Configuration config = WebConfigurationManager.OpenWebConfiguration("~");
        config.ConnectionStrings.ConnectionStrings.Add(connSttng);
        config.Save(ConfigurationSaveMode.Modified, true);
        ConfigurationManager.RefreshSection("connectionStrings");

Hope this will be use full

Developer · Accepted Answer · 2012-02-18 09:53:34Z

1

in web config:

<connectionStrings>
<add 
    name="NorthwindConnectionString"
    connectionString="Data Source=serverName;Initial 
    Catalog=Northwind;Persist Security Info=True;User
    ID=userName;Password=password"
    providerName="System.Data.SqlClient"/>
 </connectionStrings>

in view:

using System.Configuration;
string ConnectionString =ConfigurationManager.ConnectionStrings["NorthwindConnectionString"].ConnectionString.ToString();

edited Feb 18, 2012 at 9:53

Developer

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answered Feb 18, 2012 at 7:53

Deepakmahajan

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Comments

Somnath Kharat · Accepted Answer · 2014-04-25 09:30:51Z

0

In all this answer static is missing

import this namespace:

using System.Configuration;

Get connection string:

static string ConnectionString = ConfigurationManager.ConnectionStrings["ConnectionStringName"].ConnectionString.ToString();

answered Apr 25, 2014 at 9:30

Somnath Kharat

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DanielBarbarian · Accepted Answer · 2016-06-10 11:00:31Z

0

web config

<connectionStrings>   
     <add name="cn"connectionString="server=localhost;database=database_name;uid=username;password=your password"/> 
</connectionStrings>

aspx page

string constr=ConfigurationManager.ConnectionStrings["cn"].ConnectionString;
MySqlConnection con = new MySqlConnection(constr);
MySqlCommand cmd =new MySqlCommand("select * from  tbl_mastercampaign", con);

edited Jun 10, 2016 at 11:00

DanielBarbarian

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answered Jun 10, 2016 at 10:40

Priyanka Arora

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