ArcGIS Pro 2.8 API Reference Guide
ClientToMap Method (MapView)
Example 

ArcGIS.Desktop.Mapping Namespace > MapView Class : ClientToMap Method
The point that represents client coordinates relative to the top-left corner of the view.
Converts a point in client coordinates relative to the top-left corner of the view to a point in the coordinates of the map or scene. This method must be called on the MCT. Use QueuedTask.Run.
Syntax
public MapPoint ClientToMap( 
   Point clientPoint
)
Public Function ClientToMap( _
   ByVal clientPoint As Point _
) As MapPoint

Parameters

clientPoint
The point that represents client coordinates relative to the top-left corner of the view.

Return Value

The converted point in map coordinates.
Exceptions
ExceptionDescription
This method or property must be called within the lambda passed to QueuedTask.Run.
Example
Create a tool that allows you to click in the view and return the point in map coordinates that was clicked.
/*

   Copyright 2018 Esri

   Licensed under the Apache License, Version 2.0 (the "License");
   you may not use this file except in compliance with the License.
   You may obtain a copy of the License at

       http://www.apache.org/licenses/LICENSE-2.0

   Unless required by applicable law or agreed to in writing, software
   distributed under the License is distributed on an "AS IS" BASIS,
   WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.

   See the License for the specific language governing permissions and
   limitations under the License.

*/
using System;
using System.Collections.Generic;
using System.Linq;
using System.Text;
using System.Threading.Tasks;
using ArcGIS.Desktop.Mapping;
using ArcGIS.Desktop.Framework.Threading.Tasks;

namespace Examples
{
  internal class GetMapCoordinates : MapTool
  {
    protected override void OnToolMouseDown(MapViewMouseButtonEventArgs  e)
    {
      if (e.ChangedButton == System.Windows.Input.MouseButton.Left)
        e.Handled = true; //Handle the event args to get the call to the corresponding async method
    }

    protected override Task HandleMouseDownAsync(MapViewMouseButtonEventArgs e)
    {
      return QueuedTask.Run(() =>
      {
        //Convert the clicked point in client coordinates to the corresponding map coordinates.
        var mapPoint = MapView.Active.ClientToMap(e.ClientPoint);
        ArcGIS.Desktop.Framework.Dialogs.MessageBox.Show(string.Format("X: {0} Y: {1} Z: {2}",
                       mapPoint.X, mapPoint.Y, mapPoint.Z), "Map Coordinates");
      });
    }
  }
}
Requirements

Target Platforms: Windows 10, Windows 8.1

See Also

Reference

MapView Class
MapView Members