ArcGIS Pro 3.4 API Reference Guide
ArcGIS.Core.Data Namespace / Table Class / GetCount Method / GetCount(QueryFilter) Method
Used to filter the count of how many rows are currently in this Table. If set to null, all the number of rows will be returned.
Example Version

GetCount(QueryFilter) Method
Gets the count of how many rows are currently in this Table that satisfy the criteria set in the queryFilter. This method must be called on the MCT. Use QueuedTask.Run.
Syntax
public long GetCount( 
   QueryFilter queryFilter
)

Parameters

queryFilter
Used to filter the count of how many rows are currently in this Table. If set to null, all the number of rows will be returned.

Return Value

The number of rows in this table.
Exceptions
ExceptionDescription
If queryFilter is an instance of SpatialQueryFilter, either both the 'FilterGeometry' and 'SpatialRelationship' properties are set or both are not set. Otherwise, an ArgumentException will be raised.
A geodatabase-related exception has occurred.
Example
Gets the count of how many rows are currently in a Table
//Note: call within QueuedTask.Run()
Table table = featureLayer.GetTable();
long count = table.GetCount();
Gets the feature count of a layer
FeatureLayer lyr = MapView.Active.Map.GetLayersAsFlattenedList().OfType<FeatureLayer>().FirstOrDefault();
QueuedTask.Run(() =>
{
    FeatureClass featureClass = lyr.GetFeatureClass();
    long nCount = featureClass.GetCount();
});
Requirements

Target Platforms: Windows 11, Windows 10

ArcGIS Pro version: 3 or higher.
See Also