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PagedAsyncSource.GetUniqueValues Event

Allows you to get unique values.

Namespace: DevExpress.Xpf.Data

Assembly: DevExpress.Xpf.Core.v22.2.dll

NuGet Package: DevExpress.Wpf.Core


public event EventHandler<GetUniqueValuesAsyncEventArgs> GetUniqueValues

Event Data

The GetUniqueValues event's data class is GetUniqueValuesAsyncEventArgs. The following properties provide information specific to this event:

Property Description
Filter Gets the GridControl‘s filtering. Inherited from GetUniqueValuesEventArgsBase.
PropertyName Gets the property name. Inherited from GetUniqueValuesEventArgsBase.
Result Gets or sets the result of the get unique values operation (only values).
ResultWithCounts Gets or sets the result of the get unique values operation (values and their counts).


View Example: How to Bind to PagedAsyncSource

Handle the GetUniqueValues event to show unique values in a column’s drop-down filter. You can also show counts of these values.

To show only unique values, get a list of these values and specify the GetUniqueValuesAsyncEventArgs.Result property.

To show unique values with their counts, get a list of these values with counts and specify the GetUniqueValuesAsyncEventArgs.ResultWithCounts property.

source.GetUniqueValues += (o, e) => {
    if (e.PropertyName == "User") {
        e.ResultWithCounts = Task.Run(() => {
            return GetIssueDataQueryable().DistinctWithCounts(e.PropertyName);
    e.Result = Task.Run(() => {
        return GetIssueDataQueryable().Distinct(e.PropertyName);

In the code sample above, a data source implements the IQueryable interface. You can use the GridQueryableExtensions.Distinct and GridQueryableExtensions.DistinctWithCounts methods from the DevExpress.Xpf.Grid.22.2.Extensions.dll library to obtain unique values.

View Example

If you want to maintain a clean MVVM pattern and process unique values in a ViewModel, create a command and bind it to the PagedAsyncSource.GetUniqueValuesCommand property.

The following code snippet (auto-collected from DevExpress Examples) contains a reference to the GetUniqueValues event.


The algorithm used to collect these code examples remains a work in progress. Accordingly, the links and snippets below may produce inaccurate results. If you encounter an issue with code examples below, please use the feedback form on this page to report the issue.

See Also