The ConnectionString property has not been initialized

[Aviplo]

public partial class Main_Activity : System.Web.UI.Page
{
    private string constr = ConfigurationManager.AppSettings.Get("constr");
    protected void Page_Load(object sender, EventArgs e)
    {
        if (Request.QueryString["cid"] != null) { loadData(Convert.ToString(Request.QueryString["cid"])); }
        else { loadData("all"); }
    }

    private void loadData(string catId)
    {
        phContents.Controls.Clear();
        DataTable DT = new DataTable();
        OdbcCommand cmd;
        OdbcConnection conn = new OdbcConnection(constr);
        if (conn.State == ConnectionState.Closed)
        {
            conn.Open();
            OdbcCommand sql = new OdbcCommand("SET CHARACTER SET `tis620`", conn);
            sql.ExecuteNonQuery();
            sql.Dispose();
        }

I can't run this page. It said "The ConnectionString property has not been initialized" at conn.open()
can anyone help me please.I'm totally new to asp.net so any comment apreciated.

[hericles]

Double check what your constr is holding after your have created it.

[kvprajapati]

You need to save the connection strings under <connectionString/> section and read it using System.Configuration.ConfigurationManager.ConnectionString["CnStr_Name"].ConnectionString.

<connectionStrings>
     <add name="CnStr" 
          connectionString="............" 
          providerName="System.Data.SqlClient"/>
</connectionStrings>

[micah2012]

Hi please am a new member here, i came across this site while i was looking for help. Am working on a new web site on visula studio c sharp and i have one text field to select a data from the database. Please how do i connect the text field to database and how do i write the selection command.

[hericles]

Firstly you start a new thread (button at the top of the page) so you're not hijacking someone else's, its considered impolite. Then we help you:)

[JorgeM]

To clarify since Aviplo indicated he was new to asp.net, the connection string section that adatapost was referring to is located in the web.config file.