WPF不适用于坐标，而是容器。如果您想将某些内容放入DataGridCell中，请找到它并将新内容放入DataGridCell.Content中。
在我的示例中，您可以输入行号和列号，然后按执行代码按钮。这将在网格中的所需位置放置一个按钮。单击单击我后，按钮消失，显示旧单元格内容。

的数据

<Window x:Class="DataGridCell.MainWindow"
          xmlns="http://schemas.microsoft.com/winfx/2006/xaml/presentation"
          xmlns:x="http://schemas.microsoft.com/winfx/2006/xaml"
          xmlns:d="http://schemas.microsoft.com/expression/blend/2008"
          xmlns:mc="http://schemas.openxmlformats.org/markup-compatibility/2006"
          xmlns:local="clr-namespace:DataGridCell"
          mc:Ignorable="d"
          Title="MainWindow" Height="450" Width="800">
  <DockPanel>
    <StackPanel DockPanel.Dock="Top" Orientation="Horizontal" Background="LightGray">
      <Label Content="Row:"/>
      <TextBox Name="RowTextBox" Text="2"/>
      <Label Content="Column:"/>
      <TextBox Name="ColumnTextBox" Text="1"/>
      <Button DockPanel.Dock="Bottom" Content="Execute Code" Name="ExecuteButton"/>
    </StackPanel>
    <DataGrid Name="MainDataGrid" ItemsSource="{Binding}" AutoGenerateColumns="False" >
      <DataGrid.Columns>
        <DataGridTextColumn Header="Col0" Binding="{Binding Col0}"/>
        <DataGridTextColumn Header="Col1" Binding="{Binding Col1}" />
        <DataGridTextColumn Header="Col2" Binding="{Binding Col2}" />
      </DataGrid.Columns>
    </DataGrid>
  </DockPanel>
</Window>
using System.Collections.Generic;
using System.Collections.ObjectModel;
using System.Windows;
using System.Windows.Controls;
namespace DataGridCell {
  public class RowData {
    public string Col0 { get; set; }
    public string Col1 { get; set; }
    public string Col2 { get; set; }
  }
  public partial class MainWindow: Window {
    public MainWindow() {
      InitializeComponent();
      var dataList = new List<RowData>();
      dataList.Add(new RowData {Col0="0.0", Col1="0.1", Col2="0.2"});
      dataList.Add(new RowData {Col0="1.0", Col1="1.1", Col2="1.2"});
      dataList.Add(new RowData {Col0="2.0", Col1="2.1", Col2="2.2"});
      dataList.Add(new RowData {Col0="3.0", Col1="3.1", Col2="3.2"});
      ObservableCollection<RowData> custdata = new ObservableCollection<RowData>(dataList);
      MainDataGrid.DataContext = custdata;
      ExecuteButton.Click+=ExecuteButton_Click;
    }
    ContentControl cell;
    object oldContent;
    private void ExecuteButton_Click(object sender, RoutedEventArgs e) {
      var row = int.Parse(RowTextBox.Text);
      var col = int.Parse(ColumnTextBox.Text);
      var cellContent = (FrameworkElement)MainDataGrid.Columns[col].GetCellContent(MainDataGrid.Items[row]);
      cell = (ContentControl)cellContent.Parent;
      var button = new Button {Content="Click me" };
      button.Click += Button_Click;
      oldContent = cell.Content;
      cell.Content = button;
      ExecuteButton.IsEnabled = false;
    }
    private void Button_Click(object sender, RoutedEventArgs e) {
      cell.Content = oldContent;
      ExecuteButton.IsEnabled = true;
    }
  }
}

字符串
虽然这样做是可行的，但它有点像黑客。如果数据网格重新创建它的内容，你的按钮将丢失。例如，如果用户单击列标题来对网格进行排序，就会发生这种情况。
如果你真的需要单元格的尺寸，你可以用cell.ActualWidth和cell.ActualHeight来获取。但是这些值可能随时改变，例如当用户改变列的宽度时。坐标在WPF中不使用。如果你需要定义控件的确切位置，使用它的Margin来定位它。

获取单元格的中心：（当这个解决方案与winforms one相比复杂得可笑时，微软为你感到羞耻）

public Point GetCenterPointOfCell(int rowId_0Based, int colId_0Based)
    {
        Point ret = Point.Empty;
        _grid.Dispatcher.Invoke(new Action(() =>
        {
            var item = _grid.Items[rowId_0Based];
            int currentRow = _grid.SelectedIndex == -1 ? 0 : _grid.SelectedIndex;
            System.Windows.DependencyObject  dep = _grid.ItemContainerGenerator.ContainerFromIndex(currentRow);
            var dataGridRow = dep as  DataGridRow;
            if (dataGridRow is null)
            {
                string msg = $"Cannot acces row[{currentRow}] of datagrid";
                _log.Error(msg);
                throw new AccessViolationException(msg);
            }
            int visibleRowCount = (int)(_grid.ActualHeight / dataGridRow.ActualHeight * 0.8);
            if (rowId_0Based > _grid.SelectedIndex + visibleRowCount || rowId_0Based < _grid.SelectedIndex)
            {
                object targetScroll;
                if (rowId_0Based + visibleRowCount<_grid.Items.Count)
                {
                    targetScroll = _grid.Items[rowId_0Based + visibleRowCount];
                }
                else
                {
                    targetScroll = item;
                }
                _grid.ScrollIntoView(targetScroll);
                _grid.UpdateLayout();
            }
            var cellContentElement = _grid.Columns[colId_0Based].GetCellContent(item);
            if (cellContentElement == null)
                throw new Exception("cannot get cell content");
            System.Windows.Rect cellBounds = cellContentElement.TransformToAncestor(_grid).TransformBounds(new System.Windows.Rect(0, 0, cellContentElement.ActualWidth, cellContentElement.ActualHeight));
            var centerPoint = new System.Windows.Point((int)(cellBounds.X + cellBounds.Width / 2), (int)(cellBounds.Y + cellBounds.Height / 2));
            System.Windows.Point winPoint = _grid.PointToScreen(centerPoint);
            ret = new Point((int)winPoint.X, (int)winPoint.Y);
        }));
        return ret;
    }

字符串