XAML-Map-Control/MapControl/Shared/WmtsTileSource.cs

using System;
using System.Collections.Generic;

namespace MapControl;

public class WmtsTileSource(WmtsTileMatrixSet tileMatrixSet) : TileSource
{
    private readonly string uriFormat = tileMatrixSet.UriTemplate
        .Replace("{TileMatrix}", "{0}")
        .Replace("{TileCol}", "{1}")
        .Replace("{TileRow}", "{2}");

    private readonly List<WmtsTileMatrix> tileMatrixes = tileMatrixSet.TileMatrixes;

    public override Uri GetUri(int zoomLevel, int column, int row)
    {
        return zoomLevel < tileMatrixes.Count
            ? new Uri(string.Format(uriFormat, tileMatrixes[zoomLevel].Identifier, column, row))
            : null;
    }
}