I have some functions that query a database and puts the result into a gridview. It also sets a ViewState variable that contains the results of the query. When I postback, I have a load function that loads the gridview from the last results if any.
The Problem I am having is that I am getting an error that basically says that the viewstate object needs to be serialized. From what I have I am not sure how to do this.
Error: Sys.WebForms.PageRequestManagerServerErrorException: Error serializing value 'System.Collections.Generic.List
1[<>f__AnonymousType17
2[System.Int32,System.String]]' of type 'System.Collections.Generic.List1[[<>f__AnonymousType17
2[[System.Int32, mscorlib, Version=4.0.0.0, Culture=neutral, PublicKeyToken=b77a5c561934e089],[System.String, mscorlib, Version=4.0.0.0, Culture=neutral, PublicKeyToken=b77a5c561934e089]], App_Web_rjb524gi, Version=0.0.0.0, Culture=neutral, PublicKeyToken=null]].'
My code so far:
using System;
using System.Collections.Generic;
using System.Linq;
using System.Web;
using System.Web.UI;
using System.Web.UI.WebControls;
using System.Data;
using System.Runtime.Serialization;
public partial class PlayersManagement : System.Web.UI.Page
{
protected void Page_Load(object sender, EventArgs e)
{
if (!Page.IsPostBack)
{
LoadData();
}
}
public void LoadData()
{
if (ViewState["CurrentGridView"] != null || ViewState["CurrentGridView"] == "")
{
GridViewPlayers.DataSource = ViewState["CurrentGridView"];
GridViewPlayers.DataBind();
}
else
{
DBModel.DBEntities context = new DBModel.DBEntities();
var players= (from f in context.Players
where f.isDeleted == false
select new
{
f.PlayerId,
f.PlayerName
}).ToList();
GridViewPlayers.DataSource = players;
GridViewPlayers.DataBind();
}
ViewState["Sort"] = 0;
}
/**
* This method is for advance search functionality
*
*/
protected void btnSearch_Click(object sender, EventArgs e)
{
// If the search textbox is not empty
if (txtSearch.Text.Trim() != "")
{
// Call to Entity Model Framework
DBModel.DBEntities context = new DBModel.DBEntities();
//Querying the Players table
var search = (from s in context.Players
where s.PlayerName.Contains(txtSearch.Text.Trim())
select new
{
s.PlayerId,
s.PlayerName
}).ToList();
if (search.Count != 0)
{
noResults.Visible = false;
GridViewPlayers.DataSource = search;//Connecting query to the datasource Gridview
ViewState["CurrentGridView"] = search; // <---- Error cause here
GridViewPlayers.DataBind(); //Binding Gridview
}
else
{
noResults.Visible = true;
noResults.Text = "This '" + txtSearch.Text + "' Query Returned No Results";
txtSearch.Text = "";
}
}
}
protected void Gridview_Sort(object sender, GridViewSortEventArgs e)
{
//Label2.Text = e.SortExpression + " " + ConvertSortDirectionToSql(e.SortDirection);
DBModel.DBEntities context = new DBModel.DBEntities();
var players = (from b in context.Players
where b.isDeleted == false
select b);
DataTable gridviewTable = players.CopyToDataTable();
gridviewTable.DefaultView.Sort = e.SortExpression + " " + ConvertSortDirectionToSql(e.SortDirection);
GridViewPlayers.DataSource = gridviewTable;
ViewState["CurrentGridView"] = gridviewTable; <--- Also causes error
GridViewPlayers.DataBind();
}
private string ConvertSortDirectionToSql(SortDirection sortDirection)
{
string newSortDirection = String.Empty;
int sort = (ViewState["Sort"] == null) ? 0 : (int)ViewState["Sort"];
switch (sort)
{
case 0:
newSortDirection = "ASC";
ViewState["Sort"] = 1;
break;
case 1:
newSortDirection = "DESC";
ViewState["Sort"] = 0;
break;
}
return newSortDirection;
}
protected void GridViewPlayers_RowEditing(object sender, GridViewEditEventArgs e)
{
GridViewPlayers.EditIndex = e.NewEditIndex;
LoadData();
}
protected void GridViewPlayers_CancelEditRow(object sender, GridViewCancelEditEventArgs e)
{
GridViewPlayers.EditIndex = -1;
LoadData();
}
If you really want to store it in View State then you will probably want to have a type that can be marked as [Serializable]
. It looks like the anonymous type is not. So instead of using:
var search
use
List<Player> search = Query
And the class.
[Serializable]
public class Player
{
public int PlayerId {get;set;}
public string PlayerName {get;set;}
}
However, It looks like you are querying the db each time, so even if you did store in viewstate you wouldnt be gaining anything.