Problem setting Page index when working with multiple datagids on on ASP.Net Page

I have 2 DataGrid in a single page.

First DataGrid contain 2 page and 10 records per page

Second DataGrid contain 5 page and 10 records per page

When i click 3rd page of second DataGridthe following error occur

"Invalid CurrentPageIndex value. It must be >= 0 and < the PageCount."

how i can fix this error.

very urgent......

public partial class Admin_Over_all_report : System.Web.UI.Page
{
    Dataconnection dc = new Dataconnection();
    protected void Page_Load(object sender, EventArgs e)
    {
        if (IsPostBack == false)
        {
            bind();
        }
    }
    protected void dg1_PageIndexChanged(object source, DataGridPageChangedEventArgs e)
    {
        dg1.CurrentPageIndex = e.NewPageIndex;
        bind();
    }

    public void bind()
    {
        //Candidates
        string select = "select * from Candidate_Details where Today_Date='" + Request.QueryString["date"] + "'";
        dc.dt.Rows.Clear();
        dc.dt.Columns.Clear();
        dc.getdata(select);

        if (dc.dt.Rows.Count > 0)
        {
            dg1.DataSource = dc.dt;
            dg1.DataBind();
            lbltrainer.Text = dc.dt.Rows.Count.ToString() + " Records";
        }
        
        //Client
        select = "select * from Client_Details where Todaydate='" + Request.QueryString["date"] + "' order by branch";
        dc.dt.Rows.Clear();
        dc.dt.Columns.Clear();
        dc.getdata(select);

        if (dc.dt.Rows.Count > 0)
        {
            dg2.DataSource = dc.dt;
            dg2.DataBind();
            lblclient.Text = dc.dt.Rows.Count.ToString() + " Records";
        }
        else
        
       
    }
    protected void dg2_PageIndexChanged(object source, DataGridPageChangedEventArgs e)
    {
        dg2.CurrentPageIndex = e.NewPageIndex;
        bind();
    }
 
}
 
 
 
dataconnection is a class file and i have the following code
 
public class Dataconnection
{
    public SqlConnection con = new SqlConnection();
    public SqlCommand cmd = new SqlCommand();
    public SqlDataAdapter adp = new SqlDataAdapter();
    public DataTable dt = new DataTable();
    public DataTable dt1 = new DataTable();
    public DataSet ds = new DataSet();
    public int max;

    public void execute(string query)
    {
        con=new SqlConnection(ConfigurationManager.ConnectionStrings["connect"].ConnectionString);
        con.Open();
        cmd=new SqlCommand(query,con);
        cmd.ExecuteNonQuery();
        con.Close();
    }
    public DataTable getdata(string query)
    {
        con=new SqlConnection(ConfigurationManager.ConnectionStrings["connect"].ConnectionString);
        //con.Open();
        adp=new SqlDataAdapter(query,con);
        adp.Fill(dt);
        return(dt);
        
    }
    public DataTable getdata1(string query)
    {
        con = new SqlConnection(ConfigurationManager.ConnectionStrings["connect"].ConnectionString);
        //con.Open();
        adp = new SqlDataAdapter(query, con);
        adp.Fill(dt1);
        return (dt1);
    }
 
}