要在.Net平台上刷新Apache Ignite的拓扑快照，可以使用以下代码示例：

using Apache.Ignite.Core;
using Apache.Ignite.Core.Cluster.Snapshot;
using System;

class Program
{
    static void Main(string[] args)
    {
        // 创建Ignite实例
        var ignite = Ignition.Start();

        // 获取拓扑快照
        var snapshot = ignite.GetCluster().GetSnapshot();

        // 输出拓扑快照信息
        Console.WriteLine("Topology Snapshot:");
        Console.WriteLine("==================");
        Console.WriteLine($"Topology Version: {snapshot.TopologyVersion}");
        Console.WriteLine($"Topology Nodes: {snapshot.TopologyNodes.Length}");

        foreach (var node in snapshot.TopologyNodes)
        {
            Console.WriteLine($"Node Id: {node.NodeId}");
            Console.WriteLine($"Node Addresses: {string.Join(", ", node.Addresses)}");
            Console.WriteLine($"Node Is Client: {node.IsClient}");
            Console.WriteLine("==================");
        }

        // 刷新拓扑快照
        ignite.GetCluster().RefreshTopology();

        // 输出刷新后的拓扑快照信息
        snapshot = ignite.GetCluster().GetSnapshot();
        Console.WriteLine("Refreshed Topology Snapshot:");
        Console.WriteLine("==================");
        Console.WriteLine($"Topology Version: {snapshot.TopologyVersion}");
        Console.WriteLine($"Topology Nodes: {snapshot.TopologyNodes.Length}");

        foreach (var node in snapshot.TopologyNodes)
        {
            Console.WriteLine($"Node Id: {node.NodeId}");
            Console.WriteLine($"Node Addresses: {string.Join(", ", node.Addresses)}");
            Console.WriteLine($"Node Is Client: {node.IsClient}");
            Console.WriteLine("==================");
        }

        // 关闭Ignite实例
        ignite.Dispose();

        Console.ReadKey();
    }
}

这段代码首先创建了一个Ignite实例，然后使用GetSnapshot()方法获取当前的拓扑快照，并输出相关信息。接下来，调用RefreshTopology()方法刷新拓扑快照，再次获取并输出刷新后的拓扑快照信息。最后，关闭Ignite实例。

请注意，运行此代码需要在项目中引用Apache.Ignite.Core和Apache.Ignite.Log4Net NuGet包，并确保在计算机上安装了Apache Ignite。