Gridview sorting

Question

User-809753952 posted

I have a gridview with multiple columns.

I want to save all column sorting directions to a table. This will help to sort the gridview when the user visits the page next time.

How can I get all the sort expressions?

Answer 1

User839733648 posted

Hi mnmhemaj,

According to your description, I suggest that you should save the sorting directions according to different users.

You could save into a table which is related to the users.

How can I get all the sort expressions?

You may use session to achieve this. You could set and retrieve from Session like the following:

// Set
Session["SortExpression"] = "Fname";
Session["SortDirection"] = (int)SortDirection.Ascending;

// Retrieve
SortDirection sortDir = (SortDirection)Enum.ToObject(typeof(SortDirection), (int)Session["SortDirection"]);
string sortExpression = Session["SortField"].ToString(); 

I've made a sample on my side and hope it will help you to solve your issue. 

.aspx

    <form id="form1" runat="server">
        <div>
            <asp:GridView ID="GridView1" runat="server" DataKeyNames="ID" AutoGenerateColumns="True" AllowSorting="true" OnSorting="GridView1_Sorting">
            </asp:GridView>
        </div>
    </form>

code behind.

protected void Page_Load(object sender, EventArgs e)
        {
            if (!IsPostBack)
            {
                BindGrid();
            }
        }

        string constr = ConfigurationManager.ConnectionStrings["EmployeeManagementConnectionString"].ConnectionString;
        private void BindGrid()
        {
            using (SqlConnection con = new SqlConnection(constr))
            {
                DataTable dt = new DataTable();
                string myquery = "SELECT * FROM tb_Product";
                SqlCommand cmd = new SqlCommand(myquery, con);
                con.Open();
                SqlDataAdapter sda = new SqlDataAdapter(cmd);
                sda.Fill(dt);

                //Persist the table in the Session object.
                Session["ProductsTable"] = dt;

                GridView1.DataSource = Session["ProductsTable"];
                GridView1.DataBind();
                con.Close();
            }
        }

        protected void GridView1_Sorting(object sender, GridViewSortEventArgs e)
        {
            //Retrieve the table from the session object.
            DataTable dt = Session["ProductsTable"] as DataTable;

            if (dt != null)
            {
                //Sort the data.
                dt.DefaultView.Sort = e.SortExpression + " " + GetSortDirection(e.SortExpression);
                GridView1.DataSource = Session["ProductsTable"];
                GridView1.DataBind();
            }
        }
        private string GetSortDirection(string column)
        {

            // By default, set the sort direction to ascending.
            string sortDirection = "ASC";

            // Retrieve the last column that was sorted.
            string sortExpression = ViewState["SortExpression"] as string;

            if (sortExpression != null)
            {
                // Check if the same column is being sorted.
                // Otherwise, the default value can be returned.
                if (sortExpression == column)
                {
                    string lastDirection = ViewState["SortDirection"] as string;
                    if ((lastDirection != null) && (lastDirection == "ASC"))
                    {
                        sortDirection = "DESC";
                    }
                }
            }

            // Save new values in ViewState.
            ViewState["SortDirection"] = sortDirection;
            ViewState["SortExpression"] = column;

            return sortDirection;
        }

Best Regards,

Jenifer