visual studio 2012 c# catch exception error
<p>My c# coding in Master page is the following</p>

<pre><code>DBLayer odb = new DBLayer();

SqlDataReader dr;

DataSet ds = new DataSet();

protected void Page_Load(object sender, EventArgs e)
{
    if (DropDownList1.SelectedItem.ToString() == "Commercial")
    {

        bind1();
    }
    else if (DropDownList1.SelectedItem.ToString() == "Residential")
    {
        bind2();
    }
    else
    {
        bind3();
    }
}
public void bind1()
{
    string query = "select * from commercialproperty";
    dr = odb.SelectMethod(query);
    if (dr.Read())
    {
        Label11.Text = dr[0].ToString();
        Label1.Text = dr[1].ToString();
        Label2.Text = dr[2].ToString();
        Label3.Text = dr[3].ToString();
        Label4.Text = dr[4].ToString();
        Label5.Text = dr[5].ToString();
        Label6.Text = dr[6].ToString();
        Label7.Text = dr[7].ToString();
        Label8.Text = dr[8].ToString();
        Label9.Text = dr[9].ToString();
        Label10.Text = dr[10].ToString();
    }
    else
    {
        Response.Write("&lt;script&gt;alert('Record Not Found')&lt;/script&gt;");
    }
}
</code></pre>

<p>}</p>

<p>My Code In DBLayer.cs is the following</p>

<p>public class DBLayer</p>

<p>{</p>

<pre><code>    public SqlConnection _SqlConnection;

    public SqlCommand _SqlCommand;

    public SqlDataAdapter _SqlDataAdapter;

    public SqlDataReader _SqlDataReader;

    public DataSet _DataSet;

public DBLayer()
{
}
    public int InsertEditDelete(string query)
    {
        int i;
        try
        {

            _SqlConnection = new SqlConnection("server=.;user id=sa;password=sa;initial catalog=RealEstate");
            _SqlConnection.Open();
            _SqlCommand = new SqlCommand(query, _SqlConnection);
            i = _SqlCommand.ExecuteNonQuery();

        }
        catch (Exception ied)
        {
            i = -1;


        }
        finally
        {

            _SqlConnection.Dispose();
            _SqlCommand.Dispose();
            _SqlConnection.Close();

        }
        return i;
    }
    public DataSet DataAdapter(string query, string tname)
    {
        try
        {
            _SqlConnection = new SqlConnection("server=.;user id=sa;password=sa;initial catalog=RealEstate");
            _SqlConnection.Open();
            _SqlDataAdapter = new SqlDataAdapter(query, _SqlConnection);

            _DataSet = new DataSet();
            _SqlDataAdapter.Fill(_DataSet,tname);


        }
        catch (Exception ds)
        {
            _DataSet  = null;

        }
        finally
        {
            _SqlConnection.Dispose();               
            _SqlConnection.Close();
        }
        return _DataSet;
    }
    public SqlDataReader SelectMethod(string query)
    {
        try
        {
            _SqlConnection = new SqlConnection("server=.;user id=sa;password=sa;initial catalog=RealEstate");
            _SqlConnection.Open();
            _SqlCommand = new SqlCommand(query, _SqlConnection);
           _SqlDataReader  = _SqlCommand.ExecuteReader();
        }
        catch (Exception sm)
        {
         _SqlDataReader = null;

        }
        return _SqlDataReader;
    }  
</code></pre>

<p>}</p>

<p>when I run the website it's exploding at the following point,
if (dr.Read()) [Error Msg: Object reference not set to an instance of an object.]</p>

<p>what am I missing? i'm kind of a beginner :P help to solve this issue will run the site wonderfuly
thanks</p>
