ComboBox Filtering Options in Xamarin ComboBox (SfComboBox)

31 May 202124 minutes to read

The combo box enables the filer option for filtering the suggestions in the drop-down.

<StackLayout VerticalOptions="Start" HorizontalOptions="Start" Padding="30"> 
    <combobox:SfComboBox HeightRequest="40" x:Name="comboBox" IsEditableMode="true" AllowFiltering="true" MaximumDropDownHeight="150">
        <combobox:SfComboBox.DataSource>
            <ListCollection:List x:TypeArguments="x:String">
                <x:String> Afghanistan </x:String>
                <x:String> Albania </x:String>
                <x:String> Algeria</x:String>
                <x:String> American Samoa </x:String>
                <x:String> Andorra </x:String>
                <x:String> Angola </x:String>
                <x:String> Anguilla</x:String>
                <x:String> Antarctica </x:String>
                <x:String> Antigua and Barbuda </x:String>
                <x:String> Argentina </x:String>
            </ListCollection:List>
        </combobox:SfComboBox.DataSource>
    </combobox:SfComboBox>               
</StackLayout>
StackLayout layout = new StackLayout() 
{ 
    VerticalOptions = LayoutOptions.Start, 
    HorizontalOptions = LayoutOptions.Start, 
    Padding = new Thickness(30) 
};	

List<String> countryNames = new List<String>();
countryNames.Add("Afghanistan"); 
countryNames.Add("Albania");
countryNames.Add("Algeria");
countryNames.Add("American Samoa");
countryNames.Add("Andorra");
countryNames.Add("Angola");
countryNames.Add("Anguilla");
countryNames.Add("Antarctica");
countryNames.Add("Antigua and Barbuda");
countryNames.Add("Argentina");

SfComboBox comboBox = new SfComboBox();
comboBox.HeightRequest = 40;
comboBox.DataSource = countryNames; 
comboBox.IsEditableMode = true;
comboBox.AllowFiltering = true;

layout.Children.Add(comboBox); 
Content = layout;

AllowFiltering Image

Filtering types

The string comparison for filtering suggestions can be changed using the SuggestionMode property. The default filtering type is “StartsWith”, and it is case insensitive. The available filtering modes are,

  • StartsWith

  • StartsWithCaseSensitive

  • Contains

  • ContainsWithCaseSensitive

  • Equals

  • EqualsWithCaseSensitive

  • EndsWith

  • EndsWithCaseSensitive

  • Custom

Filtering words that starts with input text

Displays all the matches that start with the typed characters in control. This strategy is case in-sensitive.

<StackLayout VerticalOptions="Start" HorizontalOptions="Start" Padding="30">
	<combobox:SfComboBox HeightRequest="40" x:Name="comboBox" IsEditableMode="true" AllowFiltering="true" SuggestionMode="StartsWith">
        <combobox:SfComboBox.DataSource>
            <ListCollection:List x:TypeArguments="x:String">
                <x:String> Uganda </x:String>
                <x:String> Ukraine </x:String>
                <x:String> UUnited Arab Emirates</x:String>
                <x:String> United Kingdom</x:String>
                <x:String> United States </x:String>
            </ListCollection:List>
        </combobox:SfComboBox.DataSource>
    </combobox:SfComboBox>              
</StackLayout>
StackLayout layout = new StackLayout() 
{ 
    VerticalOptions = LayoutOptions.Start, 
    HorizontalOptions = LayoutOptions.Start, 
    Padding = new Thickness(30) 
};	    

List<String> countryNames = new List<String>();
countryNames.Add("Uganda");
countryNames.Add("Ukraine");
countryNames.Add("United Arab Emirates");
countryNames.Add("United Kingdom");
countryNames.Add("United States");

SfComboBox comboBox = new SfComboBox();
comboBox.HeightRequest = 40;
comboBox.DataSource = countryNames;
comboBox.IsEditableMode = true;
comboBox.AllowFiltering = true;
comboBox.SuggestionMode = SuggestionMode.StartsWith;
layout.Children.Add(comboBox); 
Content = layout;

Starts with image

Filtering words that starts with input text - case sensitive

Displays all the matches that start with the typed characters in control. This strategy is case sensitive.

<StackLayout VerticalOptions="Start" HorizontalOptions="Start" Padding="30">
    <comboBox:SfComboBox HeightRequest="40" x:Name="comboBox" IsEditableMode="true" AllowFiltering="true" SuggestionMode="StartsWithCaseSensitive">
        <combobox:SfComboBox.DataSource>
            <ListCollection:List x:TypeArguments="x:String">
                <x:String> Uganda </x:String>
                <x:String> Ukraine </x:String>
                <x:String> United Arab Emirates</x:String>
                <x:String> United Kingdom</x:String>
                <x:String> United States </x:String>
            </ListCollection:List>
        </combobox:SfComboBox.DataSource>
    </combobox:SfComboBox>           
</StackLayout>
StackLayout layout = new StackLayout() 
{ 
    VerticalOptions = LayoutOptions.Start, 
    HorizontalOptions = LayoutOptions.Start, 
    Padding = new Thickness(30) 
};

List<String> countryNames = new List<String>();
countryNames.Add("Uganda");
countryNames.Add("Ukraine");
countryNames.Add("United Arab Emirates");
countryNames.Add("United Kingdom");
countryNames.Add("United States");

SfComboBox comboBox = new SfComboBox();
comboBox.HeightRequest = 40;
comboBox.DataSource = countryNames;
comboBox.IsEditableMode = true;
comboBox.AllowFiltering = true;
comboBox.SuggestionMode = SuggestionMode.StartsWithCaseSensitive;
layout.Children.Add(comboBox); 
Content = layout;

Starts with casesensitive Image

Filtering words that contain input text

Displays all the matches that contain the typed characters in control. This strategy is case in-sensitive.

<StackLayout VerticalOptions="Start" HorizontalOptions="Start" Padding="30">
    <combobox:SfComboBox HeightRequest="40" x:Name="comboBox" IsEditableMode="true" AllowFiltering="true" SuggestionMode="Contains">
        <combobox:SfComboBox.DataSource>
            <ListCollection:List x:TypeArguments="x:String">
                <x:String> Uganda </x:String>
                <x:String> Ukraine </x:String>
                <x:String> United Arab Emirates</x:String>
                <x:String> United Kingdom</x:String>
                <x:String> United States </x:String>
                <x:String> Italy </x:String>
            </ListCollection:List>
        </combobox:SfComboBox.DataSource>
    </combobox:SfComboBox>                            
</StackLayout>
StackLayout layout = new StackLayout() 
{ 
    VerticalOptions = LayoutOptions.Start, 
    HorizontalOptions = LayoutOptions.Start, 
    Padding = new Thickness(30) 
};

List<String> countryNames = new List<String>();
countryNames.Add("Uganda");
countryNames.Add("Ukraine");
countryNames.Add("United Arab Emirates");
countryNames.Add("United Kingdom");
countryNames.Add("United States");
countryNames.Add("Italy");

SfComboBox comboBox = new SfComboBox();
comboBox.HeightRequest = 40;
comboBox.DataSource = countryNames;
comboBox.IsEditableMode = true;
comboBox.AllowFiltering = true;
comboBox.SuggestionMode = SuggestionMode.Contains;
layout.Children.Add(comboBox); 
Content = layout;

Contains image

Filtering words that contain input text - case sensitive

Displays all the matches that contains the typed characters in control. This strategy is case sensitive.

<StackLayout VerticalOptions="Start" HorizontalOptions="Start" Padding="30">
    <combobox:SfComboBox HeightRequest="40" x:Name="comboBox" IsEditableMode="true" AllowFiltering="true" SuggestionMode="ContainsWithCaseSensitive">
        <combobox:SfComboBox.DataSource>
            <ListCollection:List x:TypeArguments="x:String">
                <x:String> Uganda </x:String>
                <x:String> Ukraine </x:String>
                <x:String> United Arab Emirates </x:String>
                <x:String> United Kingdom </x:String>
                <x:String> United States </x:String>
                <x:String> Italy </x:String>
            </ListCollection:List>
        </combobox:SfComboBox.DataSource>
    </combobox:SfComboBox>                            
</StackLayout>
StackLayout layout = new StackLayout() 
{ 
    VerticalOptions = LayoutOptions.Start, 
    HorizontalOptions = LayoutOptions.Start, 
    Padding = new Thickness(30) 
};

List<String> countryNames = new List<String>();
countryNames.Add("Uganda");
countryNames.Add("Ukraine");
countryNames.Add("United Arab Emirates");
countryNames.Add("United Kingdom");
countryNames.Add("United States");
countryNames.Add("Italy");

SfComboBox comboBox = new SfComboBox();
comboBox.HeightRequest = 40;
comboBox.DataSource = countryNames;
comboBox.IsEditableMode = true;
comboBox.AllowFiltering = true;
comboBox.SuggestionMode = SuggestionMode.ContainsWithCaseSensitive;
layout.Children.Add(comboBox); 
Content = layout;

contains casesensitive image

Filtering words that equals the input text

Displays all the words that completely match with the typed characters in control. This strategy is case in-sensitive.

<StackLayout VerticalOptions="Start" HorizontalOptions="Start" Padding="30">
    <combobox:SfCpomboBox HeightRequest="40" x:Name="comboBox" IsEditableMode="true" AllowFiltering="true" SuggestionMode="Equals">
        <combobox:SfComboBox.DataSource>
            <ListCollection:List x:TypeArguments="x:String">
                <x:String> Uganda </x:String>
                <x:String> Ukraine </x:String>
                <x:String> United Arab Emirates </x:String>
                <x:String> United Kingdom </x:String>
                <x:String> United States </x:String>
            </ListCollection:List>
        </combobox:SfComboBox.DataSource>
    </combobox:SfComboBox>        
</StackLayout>
StackLayout layout = new StackLayout() 
{ 
    VerticalOptions = LayoutOptions.Start, 
    HorizontalOptions = LayoutOptions.Start, 
    Padding = new Thickness(30) 
};

List<String> countryNames = new List<String>();
countryNames.Add("Uganda");
countryNames.Add("Ukraine");
countryNames.Add("United Arab Emirates");
countryNames.Add("United Kingdom");
countryNames.Add("United States");
countryNames.Add("Italy");

SfComboBox comboBox = new SfComboBox();
comboBox.HeightRequest = 40;
comboBox.DataSource = countryNames;
comboBox.IsEditableMode = true;
comboBox.AllowFiltering = true;
comboBox.SuggestionMode = SuggestionMode.Equals;
layout.Children.Add(comboBox); 
Content = layout;

Filtering words that equals input text - case sensitive

Displays all the words that completely match with the typed characters in control. This strategy is case sensitive.

<StackLayout VerticalOptions="Start" HorizontalOptions="Start" Padding="30">
    <combobox:SfComboBox HeightRequest="40" x:Name="comboBox" IsEditableMode="true" AllowFiltering="true" SuggestionMode="EqualsWithCaseSensitive">
        <combobox:SfComboBox.DataSource>
            <ListCollection:List x:TypeArguments="x:String">
                <x:String> Uganda </x:String>
                <x:String> Ukraine </x:String>
                <x:String> United Arab Emirates </x:String>
                <x:String> United Kingdom </x:String>
                <x:String> United States </x:String>
            </ListCollection:List>
        </combobox:SfComboBox.DataSource>
    </combobox:SfComboBox>             
</StackLayout>
StackLayout layout = new StackLayout() 
{ 
    VerticalOptions = LayoutOptions.Start, 
    HorizontalOptions = LayoutOptions.Start, 
    Padding = new Thickness(30) 
};

List<String> countryNames = new List<String>();
countryNames.Add("Uganda");
countryNames.Add("Ukraine");
countryNames.Add("United Arab Emirates");
countryNames.Add("United Kingdom");
countryNames.Add("United States");

SfComboBox comboBox = new SfComboBox();
comboBox.HeightRequest = 40;
comboBox.DataSource = countryNames;
comboBox.IsEditableMode = true;
comboBox.AllowFiltering = true;
comboBox.SuggestionMode = SuggestionMode.EqualsWithCaseSensitive;
layout.Children.Add(comboBox); 
Content = layout;

Custom

Filters items in the suggestion list based on a custom search by user. This helps to apply our typo toleration functionality to the control.

Custom filter image

<StackLayout VerticalOptions="Start" HorizontalOptions="Start" Padding="30">
    <combobox:SfComboBox HeightRequest="40" DropDownTextSize="20" x:Name="comboBox" IsEditableMode="true" AllowFiltering="true" ComboBoxMode="Suggest" MaximumDropDownHeight="200" SuggestionMode="Custom">
        <combobox:SfComboBox.DataSource>
            <ListCollection:List x:TypeArguments="x:String">
                <x:String> Albania </x:String>
                <x:String> Algeria </x:String>
                <x:String> American Samoa </x:String>
                <x:String> Andorra </x:String>
                <x:String> Anguilla </x:String>
            </ListCollection:List>
        </combobox:SfComboBox.DataSource>
    </combobox:SfComboBox>
</StackLayout>
public ComboBoxPage()
    {
        InitializeComponent();
        StackLayout layout = new StackLayout() 
        { 
	        VerticalOptions = LayoutOptions.Start, 
	        HorizontalOptions = LayoutOptions.Start, 
	        Padding = new Thickness(30) 
        };	
        List<string> list = new List<string>();
        list.Add("Albania");
        list.Add("Algeria");
        list.Add("American Samoa");
        list.Add("Andorra");
        list.Add("Angola");
        list.Add("Anguilla");
        comboBox.ComboBoxSource = list;
        comboBox.IsEditableMode = true;
        comboBox.AllowFiltering = true;
        comboBox.Filter = ContainingSpaceFilter;

        layout.Children.Add(comboBox); 
        Content = layout;
    }
    public bool ContainingSpaceFilter(string search, object item)
    {
        string text = item.ToString().ToLower();
        if (item != null)
        {
            try
            {
                var split = search.Split(' ');
                foreach (var results in split)
                {
                    if (!text.Contains(results.ToLower()))
                    {
                        return true;
                    }
                    else
                        return false;
                }
                return true;
            }
            catch (Exception)
            {
                return (text.Contains(search));
            }
        }
        else
            return false;
    }

Filtering words that end with input text

Displays all the matches that end with the typed characters in control. This strategy is case in-sensitive.

<StackLayout VerticalOptions="Start" HorizontalOptions="Start" Padding="30">
    <combobox:SfComboBox HeightRequest="40" WidthRequest="180" x:Name="comboBox" IsEditableMode="true" AllowFiltering="true" SuggestionMode="EndsWith">
        <combobox:SfComboBox.DataSource>
            <ListCollection:List x:TypeArguments="x:String">
                <x:String> Uganda </x:String>
                <x:String> Ukraine </x:String>
                <x:String> United Arab Emirates </x:String>
                <x:String> United Kingdom </x:String>
                <x:String> United States </x:String>
            </ListCollection:List>
        </combobox:SfComboBox.DataSource>
    </combobox:SfComboBox>                            
</StackLayout>
StackLayout layout = new StackLayout() 
{ 
    VerticalOptions = LayoutOptions.Start, 
    HorizontalOptions = LayoutOptions.Start, 
    Padding = new Thickness(30) 
};

List<String> countryNames = new List<String>();
countryNames.Add("Uganda");
countryNames.Add("Ukraine");
countryNames.Add("United Arab Emirates");
countryNames.Add("United Kingdom");
countryNames.Add("United States");

SfComboBox comboBox = new SfComboBox();
comboBox.HeightRequest = 40;
comboBox.DataSource = countryNames;
comboBox.IsEditableMode = true;
comboBox.AllowFiltering = true;
comboBox.SuggestionMode = SuggestionMode.EndsWith;
layout.Children.Add(comboBox); 
Content = layout;

End with image

Filtering words that end with input text - case sensitive

Displays all the matches that ends with the typed characters in control. This strategy is case sensitive.

<StackLayout VerticalOptions="Start" HorizontalOptions="Start" Padding="30">
    <combobox:SfComboBox HeightRequest="40" x:Name="comboBox" IsEditableMode="true" AllowFiltering="true"  SuggestionMode="EndsWithCaseSensitive">
        <combobox:SfComboBox.DataSource>
            <ListCollection:List x:TypeArguments="x:String">
                <x:String> Uganda </x:String>
                <x:String> Ukraine </x:String>
                <x:String> United Arab Emirates </x:String>
                <x:String> United Kingdom </x:String>
                <x:String> United States </x:String>
            </ListCollection:List>
        </combobox:SfComboBox.DataSource>
    </combobox:SfComboBox>           
</StackLayout>
StackLayout layout = new StackLayout() 
{ 
    VerticalOptions = LayoutOptions.Start, 
    HorizontalOptions = LayoutOptions.Start, 
    Padding = new Thickness(30) 
};

List<String> countryNames = new List<String>();
countryNames.Add("Uganda");
countryNames.Add("Ukraine");
countryNames.Add("United Arab Emirates");
countryNames.Add("United Kingdom");
countryNames.Add("United States");

SfComboBox comboBox = new SfComboBox();
comboBox.HeightRequest = 40;
comboBox.DataSource = countryNames;
comboBox.IsEditableMode = true;
comboBox.AllowFiltering = true;
comboBox.SuggestionMode = SuggestionMode.EndsWithCaseSensitive;
layout.Children.Add(comboBox); 
Content = layout;

End with case sensitive image

ComboBox modes

The combo box provides three different ways to display the filtered suggestions. They are

  • Suggest - Displays suggestions in drop-down list

  • Append - Appends the first suggestion to text

  • SuggestAppend - Both suggests and appends.

The ComboBoxMode property is used to choose the suggestion display mode in SfComboBox control. The default value is Suggest.

Suggesting choices in List

The filtered suggestions are displayed in a drop-down list. User can pick an item from the list.

<StackLayout VerticalOptions="Start" HorizontalOptions="Start" Padding="30">
    <combobox:SfComboBox HeightRequest="40" x:Name="comboBox" IsEditableMode="true" AllowFiltering="true"  ComboBoxMode="Suggest">
        <combobox:SfComboBox.DataSource>
            <ListCollection:List x:TypeArguments="x:String">
                <x:String> Uganda </x:String>
                <x:String> Ukraine </x:String>
                <x:String> United Arab Emirates </x:String>
                <x:String> United Kingdom </x:String>
                <x:String> United States </x:String>
            </ListCollection:List>
        </combobox:SfComboBox.DataSource>
    </combobox:SfComboBox>                      
</StackLayout>
StackLayout layout = new StackLayout() 
{ 
    VerticalOptions = LayoutOptions.Start, 
    HorizontalOptions = LayoutOptions.Start, 
    Padding = new Thickness(30) 
};	    
List<String> countryNames = new List<String>();
countryNames.Add("Uganda");
countryNames.Add("Ukraine");
countryNames.Add("United Arab Emirates");
countryNames.Add("United Kingdom");
countryNames.Add("United States");

SfComboBox comboBox = new SfComboBox();
comboBox.HeightRequest = 40;
comboBox.DataSource = countryNames;
comboBox.IsEditableMode = true;
comboBox.AllowFiltering = true;
comboBox.ComboBoxMode = ComboBoxMode.Suggest;
layout.Children.Add(comboBox); 
Content = layout;

Suggest image

Appending suggestions to text

The first item in filtered suggestions is appended to SfComboBox text. In this mode, drop down remains closed.

<StackLayout VerticalOptions="Start" HorizontalOptions="Start" Padding="30">
    <combobox:SfComboBox HeightRequest="40" x:Name="comboBox" IsEditableMode="true" AllowFiltering="true"  ComboBoxMode="Append">
        <combobox:SfComboBox.DataSource>
            <ListCollection:List x:TypeArguments="x:String">
                <x:String> Uganda </x:String>
                <x:String> Ukraine </x:String>
                <x:String> United Arab Emirates </x:String>
                <x:String> United Kingdom </x:String>
                <x:String> United States </x:String>
            </ListCollection:List>
        </combobox:SfComboBox.DataSource>
    </combobox:SfComboBox>                       
</StackLayout>
StackLayout layout = new StackLayout() 
{ 
    VerticalOptions = LayoutOptions.Start, 
    HorizontalOptions = LayoutOptions.Start, 
    Padding = new Thickness(30) 
};

List<String> countryNames = new List<String>();
countryNames.Add("Uganda");
countryNames.Add("Ukraine");
countryNames.Add("United Arab Emirates");
countryNames.Add("United Kingdom");
countryNames.Add("United States");

SfComboBox comboBox = new SfComboBox();
comboBox.HeightRequest = 40;
comboBox.DataSource = countryNames;
comboBox.IsEditableMode = true;
comboBox.AllowFiltering = true;
comboBox.ComboBoxMode = ComboBoxMode.Append;
layout.Children.Add(comboBox); 
Content = layout;

Append image

Suggesting choices and appending suggestions to text

The text is appended to the first matched item in the suggestions collection, and filtered suggestions are displayed in a drop-down list. Users can pick an item from a list directly or use up and down keys for browsing the list.

<StackLayout VerticalOptions="Start" HorizontalOptions="Start" Padding="30">
    <combobox:SfComboBox HeightRequest="40" x:Name="comboBox" IsEditableMode="true" AllowFiltering="true"  ComboBoxMode="SuggestAppend">
        <combobox:SfComboBox.DataSource>
            <ListCollection:List x:TypeArguments="x:String">
                <x:String> Uganda </x:String>
                <x:String> Ukraine </x:String>
                <x:String> United Arab Emirates </x:String>
                <x:String> United Kingdom </x:String>
                <x:String> United States </x:String>
            </ListCollection:List>
        </combobox:SfComboBox.DataSource>
    </combobox:SfComboBox>                
</StackLayout>
StackLayout layout = new StackLayout() 
{ 
    VerticalOptions = LayoutOptions.Start, 
    HorizontalOptions = LayoutOptions.Start, 
    Padding = new Thickness(30) 
};

List<String> countryNames = new List<String>();
countryNames.Add("Uganda");
countryNames.Add("Ukraine");
countryNames.Add("United Arab Emirates");
countryNames.Add("United Kingdom");
countryNames.Add("United States");

SfComboBox comboBox = new SfComboBox();
comboBox.HeightRequest = 40;
comboBox.DataSource = countryNames;
comboBox.IsEditableMode = true;
comboBox.AllowFiltering = true;
comboBox.ComboBoxMode = ComboBoxMode.SuggestAppend;
layout.Children.Add(comboBox); 
Content = layout;

Suggest append image

NOTE

The deletion of a character is not support in this mode which is a known framework issue.