Controls / DataGrid / Filtering

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Programmatic Filtering

Programmatic Filtering can be used for external filtering. For example, disable the built-in filtering UI and to filter the data in the grid programmatically. Programmatic Filtering is achieved by adding different filter descriptors in the FilterDescriptor collection of the .NET MAUI DataGrid control.

The following descriptor types are supported:

All FilterDescriptors are located in the Telerik.Maui.Controls.Data namespace.

When using C#, you'll need to add the using statement

using Telerik.Maui.Controls.Compatibility.Common.Data;

Alternatively, if using XAML, they're be resolved through the same telerik xmlns:

xmlns:telerik="http://schemas.telerik.com/2022/xaml/maui"

Text Filter Descriptor

The TextFilterDescriptor supports the following properties:

  • PropertyName—Gets or sets the name of the property that is used to retrieve the filter value.
  • Operator—Gets or sets the TextOperator value that defines how the Value member is compared with each value from the items source.
  • Value—Gets or sets the value used in the comparisons. This is the right operand of the comparison.
  • IsCaseSensitive—Gets or sets a value that determines whether the text comparisons will be case-sensitive. The default value is True.

To use TextFilterDescriptor, you need to add its instance to the RadDataGrid.FilterDescriptors collection and to set its PropertyName property to associate it with the property from your custom objects. Then, through the Operator and Value properties, you need to set the filter condition and the value to compare. You can also use the IsCaseSensitive property to determine if the text comparisons will be case-sensitive or not.

<telerik:TextFilterDescriptor PropertyName="Country"
                              Operator="StartsWith"
                              IsCaseSensitive="False"
                              Value="En"/>

Numerical Filter Descriptor

The NumericalFilterDescriptor represents a descriptor which filters by properties of the numerical data type.

It exposes the following properties:

  • PropertyName—Gets or sets the name of the property that is used to retrieve the filter value.
  • Value—Gets or sets the value used in the comparisons. This is the right operand of the comparison.
  • Operator—Gets or sets the NumericalOperator value that defines the boolean logic behind the left and right operand comparison.
<telerik:NumericalFilterDescriptor PropertyName="StadiumCapacity"
                                   Operator="IsLessThan"
                                   Value="80000"/>

DateTime Filter Descriptor

The DateTimeFilterDescriptor is a descriptor which filters by properties of the System.DateTime data type.

It exposes the following properties:

  • PropertyName—Gets or sets the name of the property that is used to retrieve the filter value.
  • Value—Gets or sets the value used in the comparisons. This is the right operand of the comparison.
  • Operator—Gets or sets the NumericalOperator value that defines the boolean logic behind the left and right operand comparison.
<telerik:DateTimeFilterDescriptor PropertyName="Established"
                                  Operator="IsLessThan"
                                  Value="1900/01/01"/>

TimeSpan Filter Descriptor

The TimeSpanFilterDescriptor is a descriptor which filters by properties of the System.TimeSpan data type.

It exposes the following properties:

  • PropertyName—Gets or sets the name of the property that is used to retrieve the filter value.
  • Value—Gets or sets the value used in the comparisons. This is the right operand of the comparison.
  • Operator—Gets or sets the NumericalOperator value that defines the boolean logic behind the left and right operand comparison.
<telerik:TimeSpanFilterDescriptor PropertyName="Time"
                                  Operator="IsLessThan"
                                  Value="22/11/21"/>

Boolean Filter Descriptor

The BooleanFilterDescriptor is a descriptor which filters by properties of the System.Boolean data type.

It exposes the following properties:

  • PropertyName—Gets or sets the name of the property that is used to retrieve the filter value.
  • Value—Gets or sets the value used in the comparisons. This is the right operand of the comparison.
<telerik:BooleanFilterDescriptor PropertyName="IsChampion"
                                 Value="true"/>

Nested Property Text Filter Descriptor

The NestedPropertyTextFilterDescriptor is a descriptor which allows you to filter the nested properties.

It exposes the following properties:

  • PropertyName—Gets or sets the name of the property that is used to retrieve the filter value.
  • ItemPropertyGetter—Sets a custom function that implements the access to the nested property. The function gets the value accessed by the PropertyName as an input argument and returns the nested property as an output result. If ItemPropertyGetter is not set, the filter descriptor behaves the same as TextFilterDescriptor.
  • Operator—Gets or sets the TextOperator value that defines how the Value member is compared with each value from the items source.
  • Value—Gets or sets the value used in the comparisons. This is the right operand of the comparison.
  • IsCaseSensitive—Gets or sets a value that determines whether the text comparisons will be case-sensitive. The default value is True.
var filterDescriptor = new NestedPropertyTextFilterDescriptor();
filterDescriptor.PropertyName = "MyProperty";
filterDescriptor.Operator = Telerik.Maui.Controls.Data.TextOperator.EqualsTo;
filterDescriptor.Value = "Expected value";
filterDescriptor.ItemPropertyGetter = (originalPropertyValue) =>
{
    // The 'originalPropertyValue' is the object fetched by the 'PropertyName' of the descriptor. In this case, this is the value of 'MyProperty'.
    return ((MyChildObjectClass)originalPropertyValue).MyNestedProperty;
};
this.radDataGrid.FilterDescriptors.Add(filterDescriptor);

Distinct Values Filter Descriptor

The DistinctValuesFilterDescriptor is a descriptor which filters by distinct values.

It exposes the following properties:

  • PropertyName—Gets or sets the name of the property that is used to retrieve the filter value.
  • Value—Gets or sets the value used in the comparisons. This is the right operand of the comparison.
<telerik:DistinctValuesFilterDescriptor PropertyName="Country" Value="Austria" />

Composite Filter Descriptor

The CompositeFilterDescriptor represents a special FilterDescriptorBase that stores an arbitrary number of other descriptors instances. The logical AND or OR operator is applied upon all composed filters to determine the result of the PassesFilter routine.

<telerik:CompositeFilterDescriptor Operator="And">
    <telerik:CompositeFilterDescriptor.Descriptors>
        <telerik:NumericalFilterDescriptor PropertyName="StadiumCapacity"
                                           Operator="IsGreaterThan"
                                           Value="55000"/>
            <telerik:NumericalFilterDescriptor PropertyName="StadiumCapacity"
                                               Operator="IsLessThan"
                                               Value="85000"/>
    </telerik:CompositeFilterDescriptor.Descriptors>
</telerik:CompositeFilterDescriptor>

Delegate Filter Descriptor

The DelegateFilterDescriptor exposes the Filter property, which gets or sets the IFilter implementation used to check whether a data item passes the filter or not.

To use a DelegateFilterDescriptor, you need to create a class that implements the IFilter interface which will return the Key by which you want to filter.

Then, you need to add a DelegateFilterDescriptor to the RadDataGrid.FilterDescriptors collection and set its Filter property.

The following example demonstrates the CustomFilter implementation:

class CustomFilter : Telerik.Maui.Controls.Compatibility.Common.Data.IFilter
{
    public bool PassesFilter(object item)
    {
        if(item is Club club 
           && club.StadiumCapacity > 60000 
           && club.StadiumCapacity < 85000)
        {
            return true;
        }
        else
        {
            return false;
        }
    }
}

IFilter is in Telerik.Maui.Controls.Compatibility.Common.Data namespace.

Add the DelegateFilterDescriptor to the RadDataGrid instance:

dataGrid.FilterDescriptors.Add(new DelegateFilterDescriptor() { Filter = new CustomFilter()});

For a runnable example with the DataGrid Programmatic Filtering scenario, see the SDKBrowser Demo Application and go to DataGrid > Filtering > Programmatic Filtering.

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