Gridview to display after updating

Question

I'm using bulk update to update my gridview.

The user is first prompted to select dates and then click a button to display the gridview data for those dates. Update the relevant cells and then click on save.

The thing is my Gridview disappears after it gets updated. I want the Gridview to remain displaying the updated data. How do I do that?

Code Snippets:

 string connStr = ConfigurationManager.ConnectionStrings["bbsConnectionString"].ConnectionString;
        using (SqlConnection Con = new SqlConnection(connStr))
        {

            SqlDataAdapter sdr = new SqlDataAdapter(str, Con);

            sdr.SelectCommand.Parameters.AddWithValue("@startdate", startdate);
            sdr.SelectCommand.Parameters.AddWithValue("@enddate", enddate);
            DataTable dt = new DataTable();
            sdr.Fill(dt);
            if (dt.Rows.Count > 0)
            {
                GridView1.DataSource = dt;
                GridView1.DataBind();
                Button2.Visible = true;
            }



        }

    protected void Button2_Click(object sender, EventArgs e)
    {
        foreach (GridViewRow row in GridView1.Rows)
        {



            TextBox dtm = row.FindControl("DtmTextBox") as TextBox;


            string connStr = ConfigurationManager.ConnectionStrings["bbsConnectionString"].ConnectionString;
            using (SqlConnection Con = new SqlConnection(connStr))
            {
                Con.Open();
                SqlCommand cmd = new SqlCommand("Update tblAvailable set intqty=@intQty, curprice=@curprice where intresortid=@intresortid and dtm=@dtm and strroomtype=@strroomtype", Con);



                // cmd.Parameters.AddWithValue("@dtm", DateTime.ParseExact(dtm.Text.Trim(), "dd/M/yyyy", System.Globalization.CultureInfo.InvariantCulture));

                cmd.ExecuteNonQuery();
                GridView1.EditIndex = -1;
                GridView1.DataBind();
                GridView1.Visible = true;




            }

Answer 1

You have to assign datatable/DataSet to data source before bind method is called

 GridView1.DataSource = dt;
 GridView1.DataBind();

Here you are binding grid after update but not assigning DataTable to GridView1.DataSource. You can call the DataGrid method here instead of binding like this.

private void FillGrid()
{
string connStr = ConfigurationManager.ConnectionStrings["bbsConnectionString"].ConnectionString;
        using (SqlConnection Con = new SqlConnection(connStr))
        {

            SqlDataAdapter sdr = new SqlDataAdapter(str, Con);

            sdr.SelectCommand.Parameters.AddWithValue("@startdate", startdate);
            sdr.SelectCommand.Parameters.AddWithValue("@enddate", enddate);
            DataTable dt = new DataTable();
            sdr.Fill(dt);
            if (dt.Rows.Count > 0)
            {
                GridView1.DataSource = dt;
                GridView1.DataBind();
                Button2.Visible = true;
            }
        }
}
 //You should as call the method FillGrid that loads data and bind grid previously      

            cmd.ExecuteNonQuery();
            GridView1.EditIndex = -1;
            //GridView1.DataBind();
            FillGrid();
            GridView1.Visible = true;

Remove these statement and call method which bind the grid previously