C# ASP.NET ConfigurationManager ConnectionString Source Code Example

Posted by on Sunday, December 13, 2009 · Leave a Comment 

C# ASP.NET ConfigurationManager ConnectionString Source Code Example

Purpose: – Illustrates using to retrieve from web.config file in C# ASP.NET. The configuration manager can be used to do many things with regard to configuration, but this example just illustrates retrieving the connection string. Here are other methods that are available in the Configuration Manager class:

  • GetSection
  • GetWebAppSection
  • RefreshSection
  • OpenMachineConfiguration
  • OpenMappedMachineConfiguration
  • OpenExeConfiguration
  • OpenMappedExeConfiguration
  • OpenWebConfiguration
  • OpenMappedWebConfiguration

Prerequistes:

  1. Install C# (Express or Standard Edition)
  2. Install SQL Server Express
  3. Download Northwind Database
  4. Attach Northwind Database to Databases in Sql Express

Notes:

  • You can build your own library of syntax examples by using same web site over and over and just add new web forms to it.

Instructions:

  1. Use Visual Web Developer 2008
  2. Create new web site;
    • Click File/New Web Site
    • Select ASP.NET Website Template
    • Select C-Sharp for Language
    • name of Web Site could be CSharp_ASPNET_Syntax.
  3. Add New folder named “Configuration”
    • Right-click project name in solution explorer;
    • add new folder;
    • name of folder could be: Configuration
  4. Add Web Form Named ConfigurationMgrConnectionString to Configuration folder
    • Right-click Configuration folder;
    • add new item;
    • Select Web Form
    • Check place code behind in separate file
    • Web Form name could be ConfigurationMgrConnectionString
  5. Click on copy code in code below to copy code into web form ConfigurationMgrConnectionString.aspx
  6. Click on copy code in second set of code below to copy code into code-behind ConfigurationMgrConnectionString.aspx.cs
  7. Right-click on ConfigurationMgrConnectionString.aspx in solution explorer and select view in browser

Step 1: Click on Copy Code to Cut-n-paste code into ConfigurationMgrConnectionString.aspx

< %@ Page Language="C#" AutoEventWireup="true" CodeFile="ConfigurationMgrConnectionString.aspx.cs" Inherits="Configuration_ConfigurationMgrConnectionString" %>
 
< !DOCTYPE html PUBLIC "-//W3C//DTD XHTML 1.0 Transitional//EN" "http://www.w3.org/TR/xhtml1/DTD/xhtml1-transitional.dtd">
 
<html xmlns="http://www.w3.org/1999/xhtml">
<head id="Head1" runat="server">
    <title></title>
</head>
<body>
    <form id="form1" runat="server">
    <div>
        <asp :GridView ID="GridView1" runat="server">
        </asp>
    </div>
    </form>
</body>
</html>
 
 

Step 2: Click on Copy Code to Cut-n-paste code into ConfigurationMgrConnectionString.aspx.cs

using System;
using System.Data;
using System.Data.SqlClient;
using System.Configuration;
partial class Configuration_ConfigurationMgrConnectionString : System.Web.UI.Page
{
 
	protected void  // ERROR: Handles clauses are not supported in C#
Page_Load(object sender, System.EventArgs e)
	{
		SqlConnection con = new SqlConnection(ConfigurationManager.ConnectionStrings["Northwind_ConnectionString"].ConnectionString);
 
		// Create the command object
		string str = "SELECT EmployeeID, FirstName, LastName FROM Employees";
		SqlCommand cmd = new SqlCommand(str, con);
 
 
		SqlDataAdapter da = new SqlDataAdapter(cmd);
 
		DataSet ds = new DataSet();
 
		da.Fill(ds, "Employees");
		GridView1.DataSource = ds;
		GridView1.DataBind();
 
	}
}

Step 3: Click on Copy Code to Cut-n-paste code into web.config right after the appSettings section 

<connectionstrings>
    <add name="Northwind_ConnectionString"
      connectionString="Server=(local)\SQLEXPRESS;Initial Catalog=Northwind;Integrated Security=SSPI" />
  </connectionstrings>

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