Error updating fields in SQL Server front end application

Question

I am working on an application which is nearly complete except for my one page.

On the page is a gridview which is showing data from a database which works, the problem is when the user tries to update the information it is throwing out errors.

This is my code - can someone see what I am doing wrong and how I can solve this problem?

protected void OnRowUpdating(object sender, GridViewUpdateEventArgs e)
{
    GridViewRow row = GridView1.Rows[e.RowIndex];

    int Id = Convert.ToInt32(GridView1.DataKeys[e.RowIndex].Values[0]);
    int Period_Id = Convert.ToInt32(GridView1.DataKeys[e.RowIndex].Values[0]);
    int Evo_StockLink = Convert.ToInt32(GridView1.DataKeys[e.RowIndex].Values[0]);

    string Evo_ItemCode = (row.Cells[4].Controls[0] as TextBox).Text;
    string Evo_Description = (row.Cells[5].Controls[0] as TextBox).Text;

    float UnitRate = Convert.ToInt32(GridView1.DataKeys[e.RowIndex].Values[0]);
    float MinRate = Convert.ToInt32(GridView1.DataKeys[e.RowIndex].Values[0]);
    float RateBeforeSevenDays  = Convert.ToInt32(GridView1.DataKeys[e.RowIndex].Values[0]);
    float RateAfterSevenDays = Convert.ToInt32(GridView1.DataKeys[e.RowIndex].Values[0]);

    string constr = ConfigurationManager.ConnectionStrings["constr"].ConnectionString;

    using (SqlConnection con = new SqlConnection(constr))
    {
        using (SqlCommand cmd = new SqlCommand("UPDATE rates SET Period_Id = @Period_Id, Evo_StockLink = @Evo_StockLink, Evo_ItemCode = @Evo_ItemCode, Evo_Description = @Evo_Description, MinRate = @MinRate, RateBeforeSevenDays = @RateBeforeSevenDays, RateAfterSevenDays = @RateAfterSevenDays  WHERE Id = @Id"))
        {
            cmd.Parameters.AddWithValue("@Id", Id);
            cmd.Parameters.AddWithValue("@Period_Id", Period_Id);
            cmd.Parameters.AddWithValue("@Evo_StockLink", Evo_StockLink);
            cmd.Parameters.AddWithValue("@Evo_ItemCode", Evo_ItemCode);
            cmd.Parameters.AddWithValue("@Evo_Description", Evo_Description);
            cmd.Parameters.AddWithValue("@UnitRate", UnitRate);
            cmd.Parameters.AddWithValue("@MinRate", MinRate);
            cmd.Parameters.AddWithValue("@RateBeforeSevenDays", RateBeforeSevenDays);
            cmd.Parameters.AddWithValue("@RateAfterSevenDays", RateAfterSevenDays);

            cmd.Connection = con;
            con.Open();
            cmd.ExecuteNonQuery();
            con.Close();
        }
    }

    GridView1.EditIndex = -1;
    this.BindGrid();
}

The error shown is :

Index was out of range. Must be non-negative and less than the size of the collection.
Parameter name: index

Exception Details: System.ArgumentOutOfRangeException: Index was out of range. Must be non-negative and less than the size of the collection.
Parameter name: index

Source Error:

Line 61: {
Line 62: GridViewRow row = GridView1.Rows[e.RowIndex];
Line 63: int Id = Convert.ToInt32(GridView1.DataKeys[e.RowIndex].Values[0]);
Line 64: int Period_Id = Convert.ToInt32(GridView1.DataKeys[e.RowIndex].Values[0]);
Line 65: int Evo_StockLink = Convert.ToInt32(GridView1.DataKeys[e.RowIndex].Values[0]);

Answer 1

In the aspx ensure you have the DataKeyNames = "Id", you also passing all the fields using Datakeys this will update the entire DB to that value.