的版本 4 (V4) 适用于 .NET 的 Amazon SDK 已经发布！

有关重大更改和迁移应用程序的信息，请参阅[迁移主题](https://docs.amazonaws.cn/sdk-for-net/v4/developer-guide/net-dg-v4.html)。

 [https://docs.amazonaws.cn/sdk-for-net/v4/developer-guide/net-dg-v4.html](https://docs.amazonaws.cn/sdk-for-net/v4/developer-guide/net-dg-v4.html)

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。

# 显示 IAM 托管式策略的策略文档
显示策略文档

此示例向您展示如何使用 适用于 .NET 的 Amazon SDK 来显示策略文档。该应用程序创建 IAM 客户端对象，找到给定 IAM 托管式策略的默认版本，然后以 JSON 格式显示策略文档。

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](#iam-policies-display-complete-code)，并且可以按原样构建和运行。

**Topics**
+ [

## 查找默认版本
](#iam-policies-display-version)
+ [

## 显示策略文档
](#iam-policies-display-doc)
+ [

## 完整代码
](#iam-policies-display-complete-code)

## 查找默认版本


以下代码片段查找给定 IAM 策略的默认版本。

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

```
    //
    // Method to determine the default version of an IAM policy
    // Returns a string with the version
    private static async Task<string> GetDefaultVersion(
      IAmazonIdentityManagementService iamClient, string policyArn)
    {
      // Retrieve all the versions of this policy
      string defaultVersion = string.Empty;
      ListPolicyVersionsResponse reponseVersions =
        await iamClient.ListPolicyVersionsAsync(new ListPolicyVersionsRequest{
          PolicyArn = policyArn});

      // Find the default version
      foreach(PolicyVersion version in reponseVersions.Versions)
      {
        if(version.IsDefaultVersion)
        {
          defaultVersion = version.VersionId;
          break;
        }
      }

      return defaultVersion;
    }
```

## 显示策略文档


以下代码片段以 JSON 格式显示了给定 IAM 策略的策略文档。

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

```
    //
    // Method to retrieve and display the policy document of an IAM policy
    private static async Task ShowPolicyDocument(
      IAmazonIdentityManagementService iamClient, string policyArn, string defaultVersion)
    {
      // Retrieve the policy document of the default version
      GetPolicyVersionResponse responsePolicy =
        await iamClient.GetPolicyVersionAsync(new GetPolicyVersionRequest{
          PolicyArn = policyArn,
          VersionId = defaultVersion});

      // Display the policy document (in JSON)
      Console.WriteLine($"Version {defaultVersion} of the policy (in JSON format):");
      Console.WriteLine(
        $"{HttpUtility.UrlDecode(responsePolicy.PolicyVersion.Document)}");
    }
```

## 完整代码


本部分显示了本示例的相关参考和完整代码。

### SDK 参考


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

编程元素：
+ 命名空间 [Amazon。 IdentityManagement](https://docs.amazonaws.cn/sdkfornet/v4/apidocs/items/IAM/NIAM.html)

  班级 [AmazonIdentityManagementServiceClient](https://docs.amazonaws.cn/sdkfornet/v4/apidocs/items/IAM/TIAMServiceClient.html)
+ 命名空间 [Amazon。 IdentityManagement.Model](https://docs.amazonaws.cn/sdkfornet/v4/apidocs/items/IAM/NIAMModel.html)

  班级 [GetPolicyVersionRequest](https://docs.amazonaws.cn/sdkfornet/v4/apidocs/items/IAM/TGetPolicyVersionRequest.html)

  班级 [GetPolicyVersionResponse](https://docs.amazonaws.cn/sdkfornet/v4/apidocs/items/IAM/TGetPolicyVersionResponse.html)

  班级 [ListPolicyVersionsRequest](https://docs.amazonaws.cn/sdkfornet/v4/apidocs/items/IAM/TListPolicyVersionsRequest.html)

  班级 [ListPolicyVersionsResponse](https://docs.amazonaws.cn/sdkfornet/v4/apidocs/items/IAM/TListPolicyVersionsResponse.html)

  班级 [PolicyVersion](https://docs.amazonaws.cn/sdkfornet/v4/apidocs/items/IAM/TPolicyVersion.html)

### 代码


```
using System;
using System.Web;
using System.Threading.Tasks;
using Amazon.IdentityManagement;
using Amazon.IdentityManagement.Model;

namespace IamDisplayPolicyJson
{
  class Program
  {
    static async Task Main(string[] args)
    {
      // Parse the command line and show help if necessary
      if(args.Length != 1)
      {
        Console.WriteLine("\nUsage: IamDisplayPolicyJson policy-arn");
        Console.WriteLine("   policy-arn: The ARN of the policy to retrieve.");
        return;
      }
      if(!args[0].StartsWith("arn:"))
      {
        Console.WriteLine("\nCould not find policy ARN in the command-line arguments:");
        Console.WriteLine($"{args[0]}");
        return;
      }

      // Create an IAM service client
      var iamClient = new AmazonIdentityManagementServiceClient();

      // Retrieve and display the policy document of the given policy
      string defaultVersion = await GetDefaultVersion(iamClient, args[0]);
      if(string.IsNullOrEmpty(defaultVersion))
        Console.WriteLine($"Could not find the default version for policy {args[0]}.");
      else
        await ShowPolicyDocument(iamClient, args[0], defaultVersion);
    }


    //
    // Method to determine the default version of an IAM policy
    // Returns a string with the version
    private static async Task<string> GetDefaultVersion(
      IAmazonIdentityManagementService iamClient, string policyArn)
    {
      // Retrieve all the versions of this policy
      string defaultVersion = string.Empty;
      ListPolicyVersionsResponse reponseVersions =
        await iamClient.ListPolicyVersionsAsync(new ListPolicyVersionsRequest{
          PolicyArn = policyArn});

      // Find the default version
      foreach(PolicyVersion version in reponseVersions.Versions)
      {
        if(version.IsDefaultVersion)
        {
          defaultVersion = version.VersionId;
          break;
        }
      }

      return defaultVersion;
    }


    //
    // Method to retrieve and display the policy document of an IAM policy
    private static async Task ShowPolicyDocument(
      IAmazonIdentityManagementService iamClient, string policyArn, string defaultVersion)
    {
      // Retrieve the policy document of the default version
      GetPolicyVersionResponse responsePolicy =
        await iamClient.GetPolicyVersionAsync(new GetPolicyVersionRequest{
          PolicyArn = policyArn,
          VersionId = defaultVersion});

      // Display the policy document (in JSON)
      Console.WriteLine($"Version {defaultVersion} of the policy (in JSON format):");
      Console.WriteLine(
        $"{HttpUtility.UrlDecode(responsePolicy.PolicyVersion.Document)}");
    }
  }
}
```