Save and Restore RadGrid filters in the code behind

Environment

Product

RadGrid for ASP.NET AJAX

Description

Saving and Restoring filters can be as simple as saving the Grid's FilterExpression (Apply Default Filter on Initial Load). This, however, does not restore the filter functions and values for the Filter Controls automatically, it needs to be done manually.

Parsing the FilterExpressions to get the information required to restore the filter values/functions can eventually be time consuming.

Solution

Easy and efficient way to collect and restore filters in RadGrid. In order to collect all the necessary information needed for restoring the filters, loop through the Grid columns, get all filter related information and save it in the a variable. This example uses session.

For restoring, reverse the logic used to save the filters.

Buttons to Save/Restore filters

<telerik:RadButton ID="btnSaveFilters" runat="server" Text="Save Filters" OnClick="btnSaveFilters_Click"></telerik:RadButton>
<telerik:RadButton ID="btnRestoreFilters" runat="server" Text="Restore Filters" OnClick="btnRestoreFilters_Click"></telerik:RadButton>

FilterType="Classic"

<telerik:RadGrid ID="RadGrid_Classic_Filter" runat="server" AllowFilteringByColumn="true" OnNeedDataSource="RadGrid_NeedDataSource"
    FilterType="Classic">
</telerik:RadGrid>

FilterType="CheckList"

<telerik:RadGrid ID="RadGrid_CheckList_Filter" runat="server" AllowFilteringByColumn="true"
    FilterType="CheckList"
    OnNeedDataSource="RadGrid_NeedDataSource"
    OnColumnCreated="RadGrid_ColumnCreated"
    OnFilterCheckListItemsRequested="RadGrid_FilterCheckListItemsRequested">
</telerik:RadGrid>

FilterType="Combined"

<telerik:RadGrid ID="RadGrid_Combined_Filter" runat="server" AllowFilteringByColumn="true"
    FilterType="Combined"
    EnableHeaderContextMenu="true"
    EnableHeaderContextFilterMenu="true"
    OnNeedDataSource="RadGrid_NeedDataSource"
    OnColumnCreated="RadGrid_ColumnCreated"
    OnFilterCheckListItemsRequested="RadGrid_FilterCheckListItemsRequested">
</telerik:RadGrid>

FilterType="HeaderContext"

<telerik:RadGrid ID="RadGridWithHeaderContext" runat="server" AllowFilteringByColumn="true"
    FilterType="HeaderContext"
    EnableHeaderContextMenu="true"
    EnableHeaderContextFilterMenu="true"
    OnNeedDataSource="RadGrid_NeedDataSource"
    OnColumnCreated="RadGrid_ColumnCreated"
    OnFilterCheckListItemsRequested="RadGrid_FilterCheckListItemsRequested">
</telerik:RadGrid>

Code Behind Logic

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

    dt.Columns.Add(new DataColumn("OrderID", 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("ShipCountry", typeof(string)));

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

    for (int i = 0; i < 3; i++)
    {
        int index = i + 1;

        DataRow row = dt.NewRow();

        row["OrderID"] = 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["ShipCountry"] = "Country " + index;

        dt.Rows.Add(row);
    }

    return dt;
}

protected void RadGrid_NeedDataSource(object sender, GridNeedDataSourceEventArgs e)
{
    (sender as RadGrid).DataSource = OrdersTable();
}
protected void RadGrid_FilterCheckListItemsRequested(object sender, GridFilterCheckListItemsRequestedEventArgs e)
{
    string DataField = (e.Column as IGridDataColumn).GetActiveDataField();

    e.ListBox.DataSource = OrdersTable().DefaultView.ToTable(true, DataField);
    e.ListBox.DataKeyField = DataField;
    e.ListBox.DataTextField = DataField;
    e.ListBox.DataValueField = DataField;
    e.ListBox.DataBind();
}

protected void RadGrid_ColumnCreated(object sender, GridColumnCreatedEventArgs e)
{
    if (e.Column.SupportsFiltering())
    {
        e.Column.FilterCheckListEnableLoadOnDemand = true;
    }
}
protected void btnSaveFilters_Click(object sender, EventArgs e)
{
    foreach (RadGrid grid in form1.Controls.OfType<RadGrid>())
    {
        SaveFilters(grid);
    }
}
protected void btnRestoreFilters_Click(object sender, EventArgs e)
{
    foreach (RadGrid grid in form1.Controls.OfType<RadGrid>())
    {
        RestoreFilters(grid);
    }
}
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();

        foreach (GridColumn col in grid.MasterTableView.RenderColumns.Where(x => x.SupportsFiltering()))
        {
            columnFilter.ColumnName = col.UniqueName;
            columnFilter.CurrentFilterValue = col.CurrentFilterValue;
            columnFilter.CurrentFilterFunction = col.CurrentFilterFunction;
            columnFilter.AndCurrentFilterValue = col.AndCurrentFilterValue;
            columnFilter.AndCurrentFilterFunction = col.AndCurrentFilterFunction;
            columnFilter.ListOfFilterValues = col.ListOfFilterValues;
        }

        storedFilters.ListOfColumnFilter.Add(columnFilter);
    }

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

    GridFilters storedFilters = (GridFilters)Session[grid.ID];

    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;
    grid.Rebind();
}
class GridFilters
{
    public string GridID { get; set; }
    public string FilterExpression { get; set; }
    public List<ColumnFilter> ListOfColumnFilter { get; set; }
}
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; }
}

Private Function OrdersTable() As DataTable
    Dim dt As DataTable = New DataTable()
    dt.Columns.Add(New DataColumn("OrderID", GetType(Integer)))
    dt.Columns.Add(New DataColumn("OrderDate", GetType(DateTime)))
    dt.Columns.Add(New DataColumn("Freight", GetType(Decimal)))
    dt.Columns.Add(New DataColumn("ShipName", GetType(String)))
    dt.Columns.Add(New DataColumn("ShipCountry", GetType(String)))
    dt.PrimaryKey = New DataColumn() {dt.Columns("OrderID")}

    For i As Integer = 0 To 3 - 1
        Dim index As Integer = i + 1
        Dim row As DataRow = dt.NewRow()
        row("OrderID") = 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("ShipCountry") = "Country " & index
        dt.Rows.Add(row)
    Next

    Return dt
End Function

Protected Sub RadGrid_NeedDataSource(ByVal sender As Object, ByVal e As GridNeedDataSourceEventArgs)
    (TryCast(sender, RadGrid)).DataSource = OrdersTable()
End Sub

Protected Sub RadGrid_FilterCheckListItemsRequested(ByVal sender As Object, ByVal e As GridFilterCheckListItemsRequestedEventArgs)
    Dim DataField As String = (TryCast(e.Column, IGridDataColumn)).GetActiveDataField()
    e.ListBox.DataSource = OrdersTable().DefaultView.ToTable(True, DataField)
    e.ListBox.DataKeyField = DataField
    e.ListBox.DataTextField = DataField
    e.ListBox.DataValueField = DataField
    e.ListBox.DataBind()
End Sub

Protected Sub RadGrid_ColumnCreated(ByVal sender As Object, ByVal e As GridColumnCreatedEventArgs)
    If e.Column.SupportsFiltering() Then
        e.Column.FilterCheckListEnableLoadOnDemand = True
    End If
End Sub

Protected Sub btnSaveFilters_Click(ByVal sender As Object, ByVal e As EventArgs)
    For Each grid As RadGrid In form1.Controls.OfType(Of RadGrid)()
        SaveFilters(grid)
    Next
End Sub

Protected Sub btnRestoreFilters_Click(ByVal sender As Object, ByVal e As EventArgs)
    For Each grid As RadGrid In form1.Controls.OfType(Of RadGrid)()
        RestoreFilters(grid)
    Next
End Sub

Private Sub SaveFilters(ByVal grid As RadGrid)
    Dim storedFilters As GridFilters = New GridFilters()
    storedFilters.GridID = grid.ID
    storedFilters.FilterExpression = grid.MasterTableView.FilterExpression
    storedFilters.ListOfColumnFilter = New List(Of ColumnFilter)()

    For Each column As GridColumn In grid.MasterTableView.RenderColumns.Where(Function(x) x.SupportsFiltering())
        Dim columnFilter As ColumnFilter = New ColumnFilter()

        For Each col As GridColumn In grid.MasterTableView.RenderColumns.Where(Function(x) x.SupportsFiltering())
            columnFilter.ColumnName = col.UniqueName
            columnFilter.CurrentFilterValue = col.CurrentFilterValue
            columnFilter.CurrentFilterFunction = col.CurrentFilterFunction
            columnFilter.AndCurrentFilterValue = col.AndCurrentFilterValue
            columnFilter.AndCurrentFilterFunction = col.AndCurrentFilterFunction
            columnFilter.ListOfFilterValues = col.ListOfFilterValues
        Next

        storedFilters.ListOfColumnFilter.Add(columnFilter)
    Next

    Session(grid.ID) = storedFilters
End Sub

Private Sub RestoreFilters(ByVal grid As RadGrid)
    If Session(grid.ID) Is Nothing Then Return
    Dim storedFilters As GridFilters = CType(Session(grid.ID), GridFilters)
    If storedFilters Is Nothing Then Return
    grid.MasterTableView.FilterExpression = storedFilters.FilterExpression

    For Each colFilter As ColumnFilter In storedFilters.ListOfColumnFilter
        Dim col As GridColumn = 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
    Next

    Session(grid.ID) = Nothing
    grid.Rebind()
End Sub

Class GridFilters
    Public Property GridID As String
    Public Property FilterExpression As String
    Public Property ListOfColumnFilter As List(Of ColumnFilter)
End Class

Class ColumnFilter
    Public Property ColumnName As String
    Public Property CurrentFilterValue As String
    Public Property CurrentFilterFunction As GridKnownFunction
    Public Property AndCurrentFilterValue As String
    Public Property AndCurrentFilterFunction As GridKnownFunction
    Public Property ListOfFilterValues As String()
End Class

See Also

• Grid - Basic Filtering - Demo
• Grid - Excel-like Filtering - Demo
• CheckList Filtering - Documentation
• Known Filter functions - Documentation
• Accessing Cells and Rows - Documentation