适用于 .NET 的 AWS SDK V3 已进入维护模式。

我们建议您迁移到 [适用于 .NET 的 AWS SDK V4](https://docs.aws.amazon.com/sdk-for-net/v4/developer-guide/welcome.html)。有关如何迁移的更多详细信息和信息，请参阅我们的[维护模式公告](https://aws.amazon.com/blogs/developer/aws-sdk-for-net-v3-maintenance-mode-announcement/)。

本文属于机器翻译版本。若本译文内容与英语原文存在差异，则一律以英文原文为准。

# 使用 Amazon EC2 密钥对
<a name="key-pairs"></a>

Amazon EC2 使用公有密钥密码系统来加密和解密登录信息。公有密钥密码系统使用公有密钥加密数据，然后收件人可以使用私有密钥解密数据。公有和私有密钥被称为密钥对。如果要登录 EC2 实例，则必须在启动时指定密钥对，然后在连接时提供密钥对的私钥。

当您启动 EC2 实例时，您可以为其创建密钥对，或使用在启动其它实例时已使用过的密钥对。有关 Amazon EC2 密钥对的信息，请参阅 [Amazon EC2 用户指南](https://docs.aws.amazon.com/AWSEC2/latest/UserGuide/)中的[使用 Amazon EC2 密钥对](https://docs.aws.amazon.com/AWSEC2/latest/UserGuide/ec2-key-pairs.html)。

有关 APIs 和先决条件的信息，请参阅父部分 ([使用 Amazon EC2](ec2-apis-intro.md))。

**Topics**
+ [创建和显示密钥对](create-save-key-pair.md)
+ [删除密钥对](delete-key-pairs.md)

# 创建和显示密钥对
<a name="create-save-key-pair"></a>

此示例向您展示如何使用创建密钥对。 适用于 .NET 的 AWS SDK 应用程序使用新密钥对的名称和 PEM 文件的名称（扩展名为“.pem”）。其会创建密钥对，将私钥写入 PEM 文件，然后显示所有可用的密钥对。如果您不提供命令行参数，则应用程序仅显示所有可用的密钥对。

以下各节提供了此示例的片段。此后显示了[该示例的完整代码](#create-save-key-pair-complete-code)，并且可以按原样构建和运行。

**Topics**
+ [创建密钥对](#create-save-key-pair-create)
+ [显示可用的密钥对](#create-save-key-pair-display)
+ [完整代码](#create-save-key-pair-complete-code)
+ [其他注意事项](#create-save-key-pair-additional)

## 创建密钥对
<a name="create-save-key-pair-create"></a>

以下代码片段创建了一个密钥对，然后将私钥存储到给定的 PEM 文件中。

[本主题末尾](#create-save-key-pair-complete-code)的示例显示了此片段的使用情况。

```
    //
    // Method to create a key pair and save the key material in a PEM file
    private static async Task CreateKeyPair(
      IAmazonEC2 ec2Client, string keyPairName, string pemFileName)
    {
      // Create the key pair
      CreateKeyPairResponse response =
        await ec2Client.CreateKeyPairAsync(new CreateKeyPairRequest{
          KeyName = keyPairName
        });
      Console.WriteLine($"\nCreated new key pair: {response.KeyPair.KeyName}");

      // Save the private key in a PEM file
      using (var s = new FileStream(pemFileName, FileMode.Create))
      using (var writer = new StreamWriter(s))
      {
        writer.WriteLine(response.KeyPair.KeyMaterial);
      }
    }
```

## 显示可用的密钥对
<a name="create-save-key-pair-display"></a>

以下代码片段显示了可用密钥对的列表。

[本主题末尾](#create-save-key-pair-complete-code)的示例显示了此片段的使用情况。

```
    //
    // Method to show the key pairs that are available
    private static async Task EnumerateKeyPairs(IAmazonEC2 ec2Client)
    {
      DescribeKeyPairsResponse response = await ec2Client.DescribeKeyPairsAsync();
      Console.WriteLine("Available key pairs:");
      foreach (KeyPairInfo item in response.KeyPairs)
        Console.WriteLine($"  {item.KeyName}");
    }
```

## 完整代码
<a name="create-save-key-pair-complete-code"></a>

本部分显示了本示例的相关参考和完整代码。

### SDK 参考
<a name="w2aac19c15c17c15c11c19b5b1"></a>

NuGet 包裹：
+ [AWSSDK.EC2](https://www.nuget.org/packages/AWSSDK.EC2)

编程元素：
+ 命名空间 [Amazon.EC2](https://docs.aws.amazon.com/sdkfornet/v3/apidocs/items/EC2/NEC2.html)

  [Amazon EC2 客户端](https://docs.aws.amazon.com/sdkfornet/v3/apidocs/items/EC2/TEC2Client.html)
+ 命名空间 [Amazon.EC2.Model](https://docs.aws.amazon.com/sdkfornet/v3/apidocs/items/EC2/NEC2Model.html)

  班级 [CreateKeyPairRequest](https://docs.aws.amazon.com/sdkfornet/v3/apidocs/items/EC2/TCreateKeyPairRequest.html)

  班级 [CreateKeyPairResponse](https://docs.aws.amazon.com/sdkfornet/v3/apidocs/items/EC2/TCreateKeyPairResponse.html)

  班级 [DescribeKeyPairsResponse](https://docs.aws.amazon.com/sdkfornet/v3/apidocs/items/EC2/TDescribeKeyPairsResponse.html)

  班级 [KeyPairInfo](https://docs.aws.amazon.com/sdkfornet/v3/apidocs/items/EC2/TKeyPairInfo.html)

### 代码
<a name="w2aac19c15c17c15c11c19b7b1"></a>

```
using System;
using System.Threading.Tasks;
using System.IO;
using Amazon.EC2;
using Amazon.EC2.Model;
using System.Collections.Generic;

namespace EC2CreateKeyPair
{
  // = = = = = = = = = = = = = = = = = = = = = = = = = = = = = = = = = = = = = = = = = = = =
  // Class to create and store a key pair
  class Program
  {
    static async Task Main(string[] args)
    {
      // Create the EC2 client
      var ec2Client = new AmazonEC2Client();

      // Parse the command line and show help if necessary
      var parsedArgs = CommandLine.Parse(args);
      if(parsedArgs.Count == 0)
      {
        // In the case of no command-line arguments,
        // just show help and the existing key pairs
        PrintHelp();
        Console.WriteLine("\nNo arguments specified.");
        Console.Write(
          "Do you want to see a list of the existing key pairs? ((y) or n): ");
        string response = Console.ReadLine();
        if((string.IsNullOrEmpty(response)) || (response.ToLower() == "y"))
          await EnumerateKeyPairs(ec2Client);
        return;
      }

      // Get the application arguments from the parsed list
      string keyPairName =
        CommandLine.GetArgument(parsedArgs, null, "-k", "--keypair-name");
      string pemFileName =
        CommandLine.GetArgument(parsedArgs, null, "-p", "--pem-filename");
      if(string.IsNullOrEmpty(keyPairName))
        CommandLine.ErrorExit("\nNo key pair name specified." +
          "\nRun the command with no arguments to see help.");
      if(string.IsNullOrEmpty(pemFileName) || !pemFileName.EndsWith(".pem"))
        CommandLine.ErrorExit("\nThe PEM filename is missing or incorrect." +
          "\nRun the command with no arguments to see help.");

      // Create the key pair
      await CreateKeyPair(ec2Client, keyPairName, pemFileName);
      await EnumerateKeyPairs(ec2Client);
    }


    //
    // Method to create a key pair and save the key material in a PEM file
    private static async Task CreateKeyPair(
      IAmazonEC2 ec2Client, string keyPairName, string pemFileName)
    {
      // Create the key pair
      CreateKeyPairResponse response =
        await ec2Client.CreateKeyPairAsync(new CreateKeyPairRequest{
          KeyName = keyPairName
        });
      Console.WriteLine($"\nCreated new key pair: {response.KeyPair.KeyName}");

      // Save the private key in a PEM file
      using (var s = new FileStream(pemFileName, FileMode.Create))
      using (var writer = new StreamWriter(s))
      {
        writer.WriteLine(response.KeyPair.KeyMaterial);
      }
    }


    //
    // Method to show the key pairs that are available
    private static async Task EnumerateKeyPairs(IAmazonEC2 ec2Client)
    {
      DescribeKeyPairsResponse response = await ec2Client.DescribeKeyPairsAsync();
      Console.WriteLine("Available key pairs:");
      foreach (KeyPairInfo item in response.KeyPairs)
        Console.WriteLine($"  {item.KeyName}");
    }


    //
    // Command-line help
    private static void PrintHelp()
    {
      Console.WriteLine(
        "\nUsage: EC2CreateKeyPair -k <keypair-name> -p <pem-filename>" +
        "\n  -k, --keypair-name: The name you want to assign to the key pair." +
        "\n  -p, --pem-filename: The name of the PEM file to create, with a \".pem\" extension.");
    }
  }


  // = = = = = = = = = = = = = = = = = = = = = = = = = = = = = = = = = = = = = = = = = = = =
  // Class that represents a command line on the console or terminal.
  // (This is the same for all examples. When you have seen it once, you can ignore it.)
  static class CommandLine
  {
    //
    // Method to parse a command line of the form: "--key value" or "-k value".
    //
    // Parameters:
    // - args: The command-line arguments passed into the application by the system.
    //
    // Returns:
    // A Dictionary with string Keys and Values.
    //
    // If a key is found without a matching value, Dictionary.Value is set to the key
    //  (including the dashes).
    // If a value is found without a matching key, Dictionary.Key is set to "--NoKeyN",
    //  where "N" represents sequential numbers.
    public static Dictionary<string,string> Parse(string[] args)
    {
      var parsedArgs = new Dictionary<string,string>();
      int i = 0, n = 0;
      while(i < args.Length)
      {
        // If the first argument in this iteration starts with a dash it's an option.
        if(args[i].StartsWith("-"))
        {
          var key = args[i++];
          var value = key;

          // Check to see if there's a value that goes with this option?
          if((i < args.Length) && (!args[i].StartsWith("-"))) value = args[i++];
          parsedArgs.Add(key, value);
        }

        // If the first argument in this iteration doesn't start with a dash, it's a value
        else
        {
          parsedArgs.Add("--NoKey" + n.ToString(), args[i++]);
          n++;
        }
      }

      return parsedArgs;
    }

    //
    // Method to get an argument from the parsed command-line arguments
    //
    // Parameters:
    // - parsedArgs: The Dictionary object returned from the Parse() method (shown above).
    // - defaultValue: The default string to return if the specified key isn't in parsedArgs.
    // - keys: An array of keys to look for in parsedArgs.
    public static string GetArgument(
      Dictionary<string,string> parsedArgs, string defaultReturn, params string[] keys)
    {
      string retval = null;
      foreach(var key in keys)
        if(parsedArgs.TryGetValue(key, out retval)) break;
      return retval ?? defaultReturn;
    }

    //
    // Method to exit the application with an error.
    public static void ErrorExit(string msg, int code=1)
    {
      Console.WriteLine("\nError");
      Console.WriteLine(msg);
      Environment.Exit(code);
    }
  }

}
```

## 其他注意事项
<a name="create-save-key-pair-additional"></a>
+ 运行该示例后，您可以在 [Amazon EC2 控制台](https://console.aws.amazon.com/ec2/#KeyPairs)中看到新的密钥对。
+ 创建密钥对时，必须保存返回的私钥，因为以后无法检索私钥。

# 删除密钥对
<a name="delete-key-pairs"></a>

此示例向您展示如何使用删除密钥对。 适用于 .NET 的 AWS SDK 应用程序获取一个密钥对的名称。它会删除密钥对，然后显示所有可用的密钥对。如果您不提供命令行参数，则应用程序仅显示所有可用的密钥对。

以下各节提供了此示例的片段。此后显示了[该示例的完整代码](#delete-key-pairs-complete-code)，并且可以按原样构建和运行。

**Topics**
+ [删除密钥对](#delete-key-pairs-create)
+ [显示可用的密钥对](#delete-key-pairs-display)
+ [完整代码](#delete-key-pairs-complete-code)

## 删除密钥对
<a name="delete-key-pairs-create"></a>

以下代码片段删除了密钥对。

[本主题末尾](#delete-key-pairs-complete-code)的示例显示了此片段的使用情况。

```
    //
    // Method to delete a key pair
    private static async Task DeleteKeyPair(IAmazonEC2 ec2Client, string keyName)
    {
      await ec2Client.DeleteKeyPairAsync(new DeleteKeyPairRequest{
        KeyName = keyName});
      Console.WriteLine($"\nKey pair {keyName} has been deleted (if it existed).");
    }
```

## 显示可用的密钥对
<a name="delete-key-pairs-display"></a>

以下代码片段显示了可用密钥对的列表。

[本主题末尾](#delete-key-pairs-complete-code)的示例显示了此片段的使用情况。

```
    //
    // Method to show the key pairs that are available
    private static async Task EnumerateKeyPairs(IAmazonEC2 ec2Client)
    {
      DescribeKeyPairsResponse response = await ec2Client.DescribeKeyPairsAsync();
      Console.WriteLine("Available key pairs:");
      foreach (KeyPairInfo item in response.KeyPairs)
        Console.WriteLine($"  {item.KeyName}");
    }
```

## 完整代码
<a name="delete-key-pairs-complete-code"></a>

本部分显示了本示例的相关参考和完整代码。

### SDK 参考
<a name="w2aac19c15c17c15c13c19b5b1"></a>

NuGet 包裹：
+ [AWSSDK.EC2](https://www.nuget.org/packages/AWSSDK.EC2)

编程元素：
+ 命名空间 [Amazon.EC2](https://docs.aws.amazon.com/sdkfornet/v3/apidocs/items/EC2/NEC2.html)

  [Amazon EC2 客户端](https://docs.aws.amazon.com/sdkfornet/v3/apidocs/items/EC2/TEC2Client.html)
+ 命名空间 [Amazon.EC2.Model](https://docs.aws.amazon.com/sdkfornet/v3/apidocs/items/EC2/NEC2Model.html)

  班级 [https://docs.aws.amazon.com/sdkfornet/v3/apidocs/](https://docs.aws.amazon.com/sdkfornet/v3/apidocs/)

  班级 [DescribeKeyPairsResponse](https://docs.aws.amazon.com/sdkfornet/v3/apidocs/items/EC2/TDescribeKeyPairsResponse.html)

  班级 [KeyPairInfo](https://docs.aws.amazon.com/sdkfornet/v3/apidocs/items/EC2/TKeyPairInfo.html)

### 代码
<a name="w2aac19c15c17c15c13c19b7b1"></a>

```
using System;
using System.Threading.Tasks;
using Amazon.EC2;
using Amazon.EC2.Model;

namespace EC2DeleteKeyPair
{
  class Program
  {
    static async Task Main(string[] args)
    {
      // Create the EC2 client
      var ec2Client = new AmazonEC2Client();

      if(args.Length == 1)
      {
        // Delete a key pair (if it exists)
        await DeleteKeyPair(ec2Client, args[0]);

        // Display the key pairs that are left
        await EnumerateKeyPairs(ec2Client);
      }
      else
      {
        Console.WriteLine("\nUsage: EC2DeleteKeyPair keypair-name");
        Console.WriteLine("  keypair-name - The name of the key pair you want to delete.");
        Console.WriteLine("\nNo arguments specified.");
        Console.Write(
          "Do you want to see a list of the existing key pairs? ((y) or n): ");
        string response = Console.ReadLine();
        if((string.IsNullOrEmpty(response)) || (response.ToLower() == "y"))
          await EnumerateKeyPairs(ec2Client);
      }
    }


    //
    // Method to delete a key pair
    private static async Task DeleteKeyPair(IAmazonEC2 ec2Client, string keyName)
    {
      await ec2Client.DeleteKeyPairAsync(new DeleteKeyPairRequest{
        KeyName = keyName});
      Console.WriteLine($"\nKey pair {keyName} has been deleted (if it existed).");
    }


    //
    // Method to show the key pairs that are available
    private static async Task EnumerateKeyPairs(IAmazonEC2 ec2Client)
    {
      DescribeKeyPairsResponse response = await ec2Client.DescribeKeyPairsAsync();
      Console.WriteLine("Available key pairs:");
      foreach (KeyPairInfo item in response.KeyPairs)
        Console.WriteLine($"  {item.KeyName}");
    }
  }
}
```