Save and Restore the filters automatically

[Mark]

This is exactly what I need. But then I tried it.  Now my radgrid does not filter at all.  It is something in the prerender.. if I remove this.

Then filtering works again. Is there something that I am missing? It is like the preRender is canceling out my filter. I am using a needdatasource

 

https://docs.telerik.com/devtools/aspnet-ajax/knowledge-base/grid-save-and-restore-the-filters-automatically

     protected void grdProducts_PreRender(object sender, EventArgs e)
        {
            var grid = (RadGrid)sender;
            // If the flag is True
            if (IsFiltering)
            {
                // Save the Filters
                SaveFilters(grid);
                // Clear the Flag by setting its value to False
                IsFiltering = false;
            }

            // At initial Load (when not is a PostBack)
            if (!IsPostBack)
            {
                // Restore the Filters
                RestoreFilters(grid);
            }
        }

[Rumen]

Can you please confirm that the code solution provided in https://docs.telerik.com/devtools/aspnet-ajax/knowledge-base/grid-save-and-restore-the-filters-automatically#solution works for you?

I just tested it and it does work on my side as you can see in the attached video.

[Mark]

I am using that exact code. Except that I am using the needdatasource is the only difference. Do you get the same result using the needdatasource?

[Rumen]

Yes, I am getting the correct result by using the OnNeedDataSource. The sample provided in the knowledge base article binds the grid through its OnNeedDataSource property:

ASPX:

<telerik:RadGrid ID="RadGrid1" runat="server" AllowPaging="True" AllowFilteringByColumn="true" Width="800px"
    OnNeedDataSource="RadGrid1_NeedDataSource"

C#

protected void RadGrid1_NeedDataSource(object sender, GridNeedDataSourceEventArgs e)
{
    (sender as RadGrid).DataSource = OrdersTable();
}

[Mark]

Could this have something to do with it? How our columns are set up?

  <telerik:GridHyperLinkColumn DataNavigateUrlFields="SupplyID" 
                    HeaderText="<%$ Code: OrderIt.Resources.LocalizedStrings.Labels_Products %>"
                    SortExpression="Product" UniqueName="Product" DataNavigateUrlFormatString="/Pages/xxxxxx.aspx?ID={0}"
                    DataTextField="Product" CurrentFilterFunction="Contains" AutoPostBackOnFilter="True" ShowFilterIcon="false">
                </telerik:GridHyperLinkColumn>

[Attila Antal]

The Hyperlink column you have is okay. I have tested it with the example from the demo and works as expected.

 

Here is the full code for you to test:

Markup

First <a href="https://www.google.com/">Navigate to Google</a> and then Navigate back to this page.
<br />
<br />
<telerik:RadGrid ID="RadGrid1" runat="server" AllowPaging="True" AllowFilteringByColumn="true" Width="800px"
    OnNeedDataSource="RadGrid1_NeedDataSource"
    OnItemCommand="RadGrid1_ItemCommand"
    OnPreRender="RadGrid1_PreRender">
    <MasterTableView AutoGenerateColumns="False" DataKeyNames="OrderID">
        <Columns>
            <telerik:GridBoundColumn DataField="OrderID" DataType="System.Int32"
                FilterControlAltText="Filter OrderID column" HeaderText="OrderID"
                ReadOnly="True" SortExpression="OrderID" UniqueName="OrderID">
            </telerik:GridBoundColumn>
            <telerik:GridDateTimeColumn DataField="OrderDate" DataType="System.DateTime"
                FilterControlAltText="Filter OrderDate column" HeaderText="OrderDate"
                SortExpression="OrderDate" UniqueName="OrderDate">
            </telerik:GridDateTimeColumn>
            <telerik:GridNumericColumn DataField="Freight" DataType="System.Decimal"
                FilterControlAltText="Filter Freight column" HeaderText="Freight"
                SortExpression="Freight" UniqueName="Freight">
            </telerik:GridNumericColumn>
            <telerik:GridBoundColumn DataField="ShipName"
                FilterControlAltText="Filter ShipName column" HeaderText="ShipName"
                SortExpression="ShipName" UniqueName="ShipName">
            </telerik:GridBoundColumn>
            <telerik:GridBoundColumn DataField="ShipCountry"
                FilterControlAltText="Filter ShipCountry column" HeaderText="ShipCountry"
                SortExpression="ShipCountry" UniqueName="ShipCountry">
            </telerik:GridBoundColumn>

            <telerik:GridHyperLinkColumn DataNavigateUrlFields="SupplyID"
                HeaderText="Product"
                SortExpression="Product" UniqueName="Product" DataNavigateUrlFormatString="/Pages/xxxxxx.aspx?ID={0}"
                DataTextField="Product" CurrentFilterFunction="Contains" AutoPostBackOnFilter="True" ShowFilterIcon="false">
            </telerik:GridHyperLinkColumn>
        </Columns>
    </MasterTableView>
</telerik:RadGrid>

 

 

C#

// Data Binding
protected void RadGrid1_NeedDataSource(object sender, GridNeedDataSourceEventArgs e)
{
    (sender as RadGrid).DataSource = OrdersTable();
}

// Create a Global Flag with its value set to False
private bool IsFiltering = false;

// When a Grid command is fired
protected void RadGrid1_ItemCommand(object sender, GridCommandEventArgs e)
{
    // If the Command is for Filtering
    if (e.CommandName == RadGrid.FilterCommandName || e.CommandName == RadGrid.HeaderContextMenuFilterCommandName)
    {
        // Set the Flag's value to True
        IsFiltering = true;
    }
}

// Before Rendering the Grid
protected void RadGrid1_PreRender(object sender, EventArgs e)
{
    var grid = (RadGrid)sender;
    // If the flag is True
    if (IsFiltering)
    {
        // Save the Filters
        SaveFilters(grid);
        // Clear the Flag by setting its value to False
        IsFiltering = false;
    }

    // At initial Load (when not is a PostBack)
    if (!IsPostBack)
    {
        // Restore the Filters
        RestoreFilters(grid);
    }
}

#region GridDataSource

private DataTable OrdersTable()
{
    DataTable dt = new DataTable();

    dt.Columns.Add(new DataColumn("OrderID", typeof(int)));
    dt.Columns.Add(new DataColumn("SupplyID", typeof(int)));
    dt.Columns.Add(new DataColumn("OrderDate", typeof(DateTime)));
    dt.Columns.Add(new DataColumn("Freight", typeof(decimal)));
    dt.Columns.Add(new DataColumn("ShipName", typeof(string)));
    dt.Columns.Add(new DataColumn("Product", typeof(string)));
    dt.Columns.Add(new DataColumn("ShipCountry", typeof(string)));

    dt.PrimaryKey = new DataColumn[] { dt.Columns["OrderID"] };

    for (int i = 0; i < 70; i++)
    {
        int index = i + 1;

        DataRow row = dt.NewRow();

        row["OrderID"] = index;
        row["SupplyID"] = index;
        row["OrderDate"] = new DateTime(DateTime.Now.Year, DateTime.Now.Month, DateTime.Now.Day, 0, 0, 0).AddHours(index);
        row["Freight"] = index * 0.1 + index * 0.01;
        row["ShipName"] = "Name " + index;
        row["Product"] = "Product " + index;
        row["ShipCountry"] = "Country " + index;

        dt.Rows.Add(row);
    }

    return dt;
}

#endregion

#region Save/Restore Functions

private void SaveFilters(RadGrid grid)
{
    GridFilters storedFilters = new GridFilters();

    storedFilters.GridID = grid.ID;
    storedFilters.FilterExpression = grid.MasterTableView.FilterExpression;
    storedFilters.ListOfColumnFilter = new List<ColumnFilter>();
    foreach (GridColumn column in grid.MasterTableView.RenderColumns.Where(x => x.SupportsFiltering()))
    {
        ColumnFilter columnFilter = new ColumnFilter();

        columnFilter.ColumnName = column.UniqueName;
        columnFilter.CurrentFilterValue = column.CurrentFilterValue;
        columnFilter.CurrentFilterFunction = column.CurrentFilterFunction;
        columnFilter.AndCurrentFilterValue = column.AndCurrentFilterValue;
        columnFilter.AndCurrentFilterFunction = column.AndCurrentFilterFunction;
        columnFilter.ListOfFilterValues = column.ListOfFilterValues;

        storedFilters.ListOfColumnFilter.Add(columnFilter);
    }
    Session[grid.ID] = storedFilters;
}

private void RestoreFilters(RadGrid grid)
{
    if (Session[grid.ID] == null) return;

    GridFilters storedFilters = Session[grid.ID] as GridFilters;

    if (storedFilters == null) return;

    grid.MasterTableView.FilterExpression = storedFilters.FilterExpression;

    foreach (ColumnFilter colFilter in storedFilters.ListOfColumnFilter)
    {
        GridColumn col = grid.MasterTableView.GetColumn(colFilter.ColumnName);

        col.CurrentFilterValue = colFilter.CurrentFilterValue;
        col.CurrentFilterFunction = colFilter.CurrentFilterFunction;
        col.AndCurrentFilterValue = colFilter.AndCurrentFilterValue;
        col.AndCurrentFilterFunction = colFilter.AndCurrentFilterFunction;
        col.ListOfFilterValues = colFilter.ListOfFilterValues;
    }
    //Session[grid.ID] = null; //Only clear the session if you're sure the filters are no longer needed.
    grid.Rebind();
}
#endregion

#region Models
public class GridFilters
{
    public string GridID { get; set; }
    public string FilterExpression { get; set; }
    public List<ColumnFilter> ListOfColumnFilter { get; set; }
}
public class ColumnFilter
{
    public string ColumnName { get; set; }
    public string CurrentFilterValue { get; set; }
    public GridKnownFunction CurrentFilterFunction { get; set; }
    public string AndCurrentFilterValue { get; set; }
    public GridKnownFunction AndCurrentFilterFunction { get; set; }
    public string[] ListOfFilterValues { get; set; }
}
#endregion

 

 

 

 

 

 

 

[Mark]

The reason why it was not working for me or showing any errors was because I was using RadAjaxManager on the grid. Once I removed that I got the following error.

Unable to serialize the session state. In 'StateServer' and 'SQLServer' mode, ASP.NET will serialize the session state objects, and as a result non-serializable objects or MarshalByRef objects are not permitted. The same restriction applies if similar serialization is done by the custom session state store in 'Custom' mode.

xxxx.Views.SupplyProducts+GridFilters' in Assembly 'xxxxx, Version=6.0.1.0, Culture=neutral, PublicKeyToken=1d62ee94bf50e8a2' is not marked as serializable.

 

I am storing my sessionState in SQL using SqlInMemoryProvider

 

 

[Mark]

Is there a way around this?

[Attila Antal]

Hi Mark,

I have tested my sample by enabling AJAX for the Grid using RadAjaxManager and it worked.

I think the problem you are experiencing may be related to something else. It could be an incorrect/unsupported AJAX structure. I suggest reviewing the Understanding AJAX Controls article for in-depth information about AJAX Components and how to use them. Once you get the correct AJAX settings, everything will work as expected.

[Mark]

To get around the issue of using the SessionState SqlInMemoryProvider i used ApplicationState to save the grid filtering. Not the best. But it will do.