Save and Load Filter Settings

To save and load column filters, you would have to create a simple property bag class that will hold all relevant information.

public class FilterDescriptorProxy 
{ 
    public Telerik.Windows.Data.FilterOperator Operator { get; set; } 
    public object Value { get; set; } 
    public bool IsCaseSensitive { get; set; } 
} 
 
public class FilterSetting 
{ 
    public string ColumnUniqueName { get; set; } 
    public List<object> SelectedDistinctValues = new List<object>(); 
    public FilterDescriptorProxy Filter1 { get; set; } 
    public Telerik.Windows.Data.FilterCompositionLogicalOperator FieldFilterLogicalOperator { get; set; } 
    public FilterDescriptorProxy Filter2 { get; set; } 
} 

Public Class FilterDescriptorProxy 
    Public Property Operator As Telerik.Windows.Data.FilterOperator 
        Get 
            Return m_Operator 
        End Get 
        Set(value As Telerik.Windows.Data.FilterOperator) 
            m_Operator = value 
        End Set 
    End Property 
    Private m_Operator As Telerik.Windows.Data.FilterOperator 
    Public Property Value() As Object 
        Get 
            Return m_Value 
        End Get 
        Set(value As Object) 
            m_Value = value 
        End Set 
    End Property 
    Private m_Value As Object 
    Public Property IsCaseSensitive() As Boolean 
        Get 
            Return m_IsCaseSensitive 
        End Get 
        Set(value As Boolean) 
            m_IsCaseSensitive = value 
        End Set 
    End Property 
    Private m_IsCaseSensitive As Boolean 
End Class 
 
Public Class FilterSetting 
    Public Property ColumnUniqueName() As String 
        Get 
            Return m_ColumnUniqueName 
        End Get 
        Set(value As String) 
            m_ColumnUniqueName = value 
        End Set 
    End Property 
    Private m_ColumnUniqueName As String 
    Public SelectedDistinctValues As New List(Of Object)() 
    Public Property Filter1() As FilterDescriptorProxy 
        Get 
            Return m_Filter1 
        End Get 
        Set(value As FilterDescriptorProxy) 
            m_Filter1 = value 
        End Set 
    End Property 
    Private m_Filter1 As FilterDescriptorProxy 
    Public Property FieldFilterLogicalOperator() As Telerik.Windows.Data.FilterCompositionLogicalOperator 
        Get 
            Return m_FieldFilterLogicalOperator 
        End Get 
        Set(value As Telerik.Windows.Data.FilterCompositionLogicalOperator) 
            m_FieldFilterLogicalOperator = value 
        End Set 
    End Property 
    Private m_FieldFilterLogicalOperator As Telerik.Windows.Data.FilterCompositionLogicalOperator 
    Public Property Filter2() As FilterDescriptorProxy 
        Get 
            Return m_Filter2 
        End Get 
        Set(value As FilterDescriptorProxy) 
            m_Filter2 = value 
        End Set 
    End Property 
    Private m_Filter2 As FilterDescriptorProxy 
End Class 

To save the settings you need to read the current filtering information from RadGridView and store it in a collection of these property bag objects. You can then take this collection and serialize it to a medium of your choice a database or an XML file, for example, by using RadPersistenceFramework.

public static IEnumerable<FilterSetting> SaveColumnFilters(Telerik.Windows.Controls.GridView.GridViewDataControl grid) 
{ 
    IList<FilterSetting> settings = new List<FilterSetting>(); 
 
    foreach (Telerik.Windows.Data.IFilterDescriptor filter in grid.FilterDescriptors) 
    { 
        Telerik.Windows.Controls.GridView.IColumnFilterDescriptor columnFilter = filter as Telerik.Windows.Controls.GridView.IColumnFilterDescriptor; 
        if (columnFilter != null) 
        { 
            FilterSetting setting = new FilterSetting(); 
 
            setting.ColumnUniqueName = columnFilter.Column.UniqueName; 
 
            setting.SelectedDistinctValues.AddRange(columnFilter.DistinctFilter.DistinctValues); 
 
            if (columnFilter.FieldFilter.Filter1.IsActive) 
            { 
                setting.Filter1 = new FilterDescriptorProxy(); 
                setting.Filter1.Operator = columnFilter.FieldFilter.Filter1.Operator; 
                setting.Filter1.Value = columnFilter.FieldFilter.Filter1.Value; 
                setting.Filter1.IsCaseSensitive = columnFilter.FieldFilter.Filter1.IsCaseSensitive; 
            } 
 
            setting.FieldFilterLogicalOperator = columnFilter.FieldFilter.LogicalOperator; 
 
            if (columnFilter.FieldFilter.Filter2.IsActive) 
            { 
                setting.Filter2 = new FilterDescriptorProxy(); 
                setting.Filter2.Operator = columnFilter.FieldFilter.Filter2.Operator; 
                setting.Filter2.Value = columnFilter.FieldFilter.Filter2.Value; 
                setting.Filter2.IsCaseSensitive = columnFilter.FieldFilter.Filter2.IsCaseSensitive; 
            } 
 
            settings.Add(setting); 
        } 
    } 
 
    return settings; 
} 
 
public static void LoadColumnFilters(Telerik.Windows.Controls.GridView.GridViewDataControl grid 
    , IEnumerable<FilterSetting> savedSettings) 
{ 
    grid.FilterDescriptors.SuspendNotifications(); 
 
    foreach (FilterSetting setting in savedSettings) 
    { 
        Telerik.Windows.Controls.GridViewColumn column = grid.Columns[setting.ColumnUniqueName]; 
 
        Telerik.Windows.Controls.GridView.IColumnFilterDescriptor columnFilter = column.ColumnFilterDescriptor; 
 
        foreach (object distinctValue in setting.SelectedDistinctValues) 
        { 
            columnFilter.DistinctFilter.AddDistinctValue(distinctValue); 
        } 
 
        if (setting.Filter1 != null) 
        { 
            columnFilter.FieldFilter.Filter1.Operator = setting.Filter1.Operator; 
            columnFilter.FieldFilter.Filter1.Value = setting.Filter1.Value; 
            columnFilter.FieldFilter.Filter1.IsCaseSensitive = setting.Filter1.IsCaseSensitive; 
        } 
 
        columnFilter.FieldFilter.LogicalOperator = setting.FieldFilterLogicalOperator; 
 
        if (setting.Filter2 != null) 
        { 
            columnFilter.FieldFilter.Filter2.Operator = setting.Filter2.Operator; 
            columnFilter.FieldFilter.Filter2.Value = setting.Filter2.Value; 
            columnFilter.FieldFilter.Filter2.IsCaseSensitive = setting.Filter2.IsCaseSensitive; 
        } 
    } 
 
    grid.FilterDescriptors.ResumeNotifications(); 
} 

Public Shared Function SaveColumnFilters(grid As Telerik.Windows.Controls.GridView.GridViewDataControl) As IEnumerable(Of FilterSetting) 
    Dim settings As IList(Of FilterSetting) = New List(Of FilterSetting)() 
 
    For Each filter As Telerik.Windows.Data.IFilterDescriptor In grid.FilterDescriptors 
        Dim columnFilter As Telerik.Windows.Controls.GridView.IColumnFilterDescriptor = TryCast(filter, Telerik.Windows.Controls.GridView.IColumnFilterDescriptor) 
        If columnFilter IsNot Nothing Then 
            Dim setting As New FilterSetting() 
 
            setting.ColumnUniqueName = columnFilter.Column.UniqueName 
 
            setting.SelectedDistinctValues.AddRange(columnFilter.DistinctFilter.DistinctValues) 
 
            If columnFilter.FieldFilter.Filter1.IsActive Then 
                setting.Filter1 = New FilterDescriptorProxy() 
                setting.Filter1.[Operator] = columnFilter.FieldFilter.Filter1.[Operator] 
                setting.Filter1.Value = columnFilter.FieldFilter.Filter1.Value 
                setting.Filter1.IsCaseSensitive = columnFilter.FieldFilter.Filter1.IsCaseSensitive 
            End If 
 
            setting.FieldFilterLogicalOperator = columnFilter.FieldFilter.LogicalOperator 
 
            If columnFilter.FieldFilter.Filter2.IsActive Then 
                setting.Filter2 = New FilterDescriptorProxy() 
                setting.Filter2.[Operator] = columnFilter.FieldFilter.Filter2.[Operator] 
                setting.Filter2.Value = columnFilter.FieldFilter.Filter2.Value 
                setting.Filter2.IsCaseSensitive = columnFilter.FieldFilter.Filter2.IsCaseSensitive 
            End If 
 
            settings.Add(setting) 
        End If 
    Next 
 
    Return settings 
End Function 
 
Public Shared Sub LoadColumnFilters(grid As Telerik.Windows.Controls.GridView.GridViewDataControl, savedSettings As IEnumerable(Of FilterSetting)) 
    grid.FilterDescriptors.SuspendNotifications() 
 
    For Each setting As FilterSetting In savedSettings 
        Dim column As Telerik.Windows.Controls.GridViewColumn = grid.Columns(setting.ColumnUniqueName) 
 
        Dim columnFilter As Telerik.Windows.Controls.GridView.IColumnFilterDescriptor = column.ColumnFilterDescriptor 
 
        For Each distinctValue As Object In setting.SelectedDistinctValues 
            columnFilter.DistinctFilter.AddDistinctValue(distinctValue) 
        Next 
 
        If setting.Filter1 IsNot Nothing Then 
            columnFilter.FieldFilter.Filter1.[Operator] = setting.Filter1.[Operator] 
            columnFilter.FieldFilter.Filter1.Value = setting.Filter1.Value 
            columnFilter.FieldFilter.Filter1.IsCaseSensitive = setting.Filter1.IsCaseSensitive 
        End If 
 
        columnFilter.FieldFilter.LogicalOperator = setting.FieldFilterLogicalOperator 
 
        If setting.Filter2 IsNot Nothing Then 
            columnFilter.FieldFilter.Filter2.[Operator] = setting.Filter2.[Operator] 
            columnFilter.FieldFilter.Filter2.Value = setting.Filter2.Value 
            columnFilter.FieldFilter.Filter2.IsCaseSensitive = setting.Filter2.IsCaseSensitive 
        End If 
    Next 
 
    grid.FilterDescriptors.ResumeNotifications() 
End Sub 

Note that when the filters are being restored we suspend and resume the notifications in order to perform the filtering in a single batch.

When you deserialize the filter settings, you only need to find the respective column and apply the information stored in the property bag to the column filter.

private IEnumerable<FilterSetting> serializedSettings; 
 
private void OnSaveButtonClick(object sender, RoutedEventArgs e) 
{ 
    IEnumerable<FilterSetting> savedSettings = SaveColumnFilters(this.radGridView); 
 
    // You can serialize the saved settings in any way that you like from here on. 
    this.serializedSettings = savedSettings; 
} 
 
private void OnLoadButtonClick(object sender, RoutedEventArgs e) 
{ 
    // You should deserialize the settings from where you have serialized them. 
    IEnumerable<FilterSetting> savedSettings = this.serializedSettings; 
 
    LoadColumnFilters(this.radGridView, savedSettings); 
} 

Private serializedSettings As IEnumerable(Of FilterSetting) 
 
Private Sub OnSaveButtonClick(sender As Object, e As RoutedEventArgs) 
    Dim savedSettings As IEnumerable(Of FilterSetting) = SaveColumnFilters(Me.radGridView) 
 
    ' You can serialize the saved settings in any way that you like from here on. 
    Me.serializedSettings = savedSettings 
End Sub 
 
Private Sub OnLoadButtonClick(sender As Object, e As RoutedEventArgs) 
    ' You should deserialize the settings from where you have serialized them. 
    Dim savedSettings As IEnumerable(Of FilterSetting) = Me.serializedSettings 
 
    LoadColumnFilters(Me.radGridView, savedSettings) 
End Sub 

More about this you can learn here.

You can also check the Save and Load Settings for RadGridView article.