Select sqldasource query from dropdownlist

Question

I have a grid which has a dasource selected sqlDataSource2. I have not built any query in the datasource. I have a dropdownlist with two items and I would like to select the query from the dropdownlist and after selection of the query update the grid to show the result. This is what I have tried so far:

protected void Page_Load(object sender, EventArgs e)
{
    Query1();
}

 protected void Query1()
{
    //if (this.IsPostBack)
 {
   SqlConnection conn = new SqlConnection();
    conn.ConnectionString = ConfigurationManager.ConnectionStrings["PMIcommConnectionString"].ConnectionString;
    SqlDataSource2.SelectCommand = @"SELECT YEAR(custDecDate), SUM(valueXX), SUM(valueYY)
                                     FROM bids
                                    WHERE forBid ='"+ DropDownList3.SelectedValue +"'GROUP BY YEAR(custDecDate)'";
    SqlDataSource2.DataBind();
    RadGrid1.DataBind();
 }
}

This is my connection string:

<add name="PMIcommConnectionString" connectionString="Data
Source=WIN-72PL3253COR\SQLEXPRESS;Initial Catalog=PMIcomm;Integrated
Security=True" providerName="System.Data.SqlClient" />

I get an error "Connection string has not been initialized" on the last line. How can I make this working? Beside the error I am getting, I am not sure if this is the correct way to do this. Sorry for asking such simple thing, I am a selflearning beginner.

Answer 1

The connection string is not in AppSettings.

What you're looking for is in:

SqlConnection conn = new SqlConnection();

conn.ConnectionString = ConfigurationManager.ConnectionStrings["PMIcommConnectionString"].ConnectionStri‌​ng;

Answer 2

Web.config:

 <connectionStrings>
    <add name="PMIcommConnectionString" connectionString="Data
    Source=WIN-72PL3253COR\SQLEXPRESS;Initial Catalog=PMIcomm;Integrated
    Security=True"/>
 </connectionStrings>

Code Behind .cs:

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

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